Forest Management 1606925040, 9781606925041

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FOREST MANAGEMENT No part of this digital document may be reproduced, stored in a retrieval system or transmitted in any form or by any means. The publisher has taken reasonable care in the preparation of this digital document, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained herein. This digital document is sold with the clear understanding that the publisher is not engaged in rendering legal, medical or any other professional services.

FOREST MANAGEMENT

STEVEN P. GROSSBERG EDITOR

Nova Science Publishers, Inc. New York

Copyright © 2009 by Nova Science Publishers, Inc.

All rights reserved. No part of this book may be reproduced, stored in a retrieval system or transmitted in any form or by any means: electronic, electrostatic, magnetic, tape, mechanical photocopying, recording or otherwise without the written permission of the Publisher. For permission to use material from this book please contact us: Telephone 631-231-7269; Fax 631-231-8175 Web Site: http://www.novapublishers.com NOTICE TO THE READER The Publisher has taken reasonable care in the preparation of this book, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained in this book. The Publisher shall not be liable for any special, consequential, or exemplary damages resulting, in whole or in part, from the readers‘ use of, or reliance upon, this material. Any parts of this book based on government reports are so indicated and copyright is claimed for those parts to the extent applicable to compilations of such works. Independent verification should be sought for any data, advice or recommendations contained in this book. In addition, no responsibility is assumed by the publisher for any injury and/or damage to persons or property arising from any methods, products, instructions, ideas or otherwise contained in this publication. This publication is designed to provide accurate and authoritative information with regard to the subject matter covered herein. It is sold with the clear understanding that the Publisher is not engaged in rendering legal or any other professional services. If legal or any other expert assistance is required, the services of a competent person should be sought. FROM A DECLARATION OF PARTICIPANTS JOINTLY ADOPTED BY A COMMITTEE OF THE AMERICAN BAR ASSOCIATION AND A COMMITTEE OF PUBLISHERS. LIBRARY OF CONGRESS CATALOGING-IN-PUBLICATION DATA Grossberg, Steven P. Forest management / Steven P. Grossberg. p. cm. Includes index. ISBN 978-1-61209-697-1 (eBook) 1. Forest management. 2. Forests and forestry. I. Title. SD373.G84 2009 634.9'2--dc22 2009002409

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CONTENTS Preface

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Review and Research Articles Chapter 1

Chapter 2

Chapter 3

Chapter 4

Chapter 5

Chapter 6

A Decomposition Approach to Integrated Forest Harvest Scheduling and Access Planning David M. Nanang and Grant K. Hauer

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Reduced-Impact Logging and Post-Harvest Management in the Atlantic Forest of Argentina: Alternative Approaches to Enhance Regeneration and Growth of Canopy Trees Paula I. Campanello, Lía Montti, Patricio Mac Donagh and Guillermo Goldstein

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A Decision Support System Linking Forest Policy with Sustainable Forest Management Planning in Private Forests in Ireland Frank Barrett and Maarten Nieuwenhuis

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Ecological Restoration in Degraded Drylands: The Need to Improve the Seedling Quality and Site Conditions in the Field E. Chirino, A. Vilagrosa, J. Cortina, A. Valdecantos, D. Fuentes, R. Trubat, V.C. Luis, J. Puértolas, S. Bautista, M.J. Baeza, J.L. Peñuelas and V. R. Vallejo Selection of Restoration and Conservation Areas Using Species Ecological Niche Modeling: A Case Study of the River Otter Lontra Longicaudis Annectens in Central Mexico Verónica Cirelli and Víctor Sánchez-Cordero Environmental Impacts of Caatinga Forest Management - A Study Case Frans Pareyn, Enrique Riegelhaupt and Maria Auxiliadora Gariglio

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Contents

vi Chapter 7

Chapter 8

Forest Management within Protected Areas: The Social Production of Nature in the Dadia Forest Reserve, Greece Tasos Hovardas A Comparison of Forest Resources in Selected Jurisdictions of North America and Europe: Some Implications for MacroSustainability Assessment Gordon M. Hickey

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Chapter 9

Semi-Arid Zone Afforestation in Northern Israel: A Review Paul Ginsberg and Nir Atzmon

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Chapter 10

Olive Tree Growth in Tunisia: Types, Limitations and Influences Ben Ahmed, B. Ben Rouina and M. Boukhris

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Short Communications Communication A Rotation Age Determination for Even-Aged Forest Plantations Pete Bettinger and Rongxia Li

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Communication B Moving Targets and Rolling Milestones in Forest Management Sen Wang Index

305 309

PREFACE Forest management includes a range of human interventions that affect forest ecosystems. These activities include both conservation and economic activities, such as extraction of timber, planting and replanting of various species, cutting roads and pathways through forests, and techniques for preventing or making outbreaks of fire. In developed countries, the environment has increased public awareness of natural resource policy, including forest management. As a direct result, primary concerns regarding forest management have shifted from the extraction of timber to other forest resources including wildlife, watershed management, and recreation. This shift in public values has also caused many in the public to mistrust resource management professionals. This new book presents the latest research in this field. Chapter 1 - This chapter presents the results of a mixed-integer non-linear programming (MINLP) model that integrates access road development with forest harvest scheduling. A Model II forest scheduling model that maximized net present value of timber products subject to mill capacity, multiple mill and product demands, regeneration, area, and access constraints was specified. The model was applied to an operationally-sized Forest Management Agreement (FMA) area in central Alberta, Canada. The resulting model had approximately 2.6 million decision variables and about 96,000 constraints, and was used to examine the impacts of access development on harvest scheduling. The results show that the inclusion of road access costs concentrated forest management activities to fewer locations over the planning period compared to when road construction costs were zero. Also, positive access costs reduced the frequency with which locations are accessed during the planning horizon. The model provides important shadow price information on the various constraints in the model that gives insights into future production costs or timber prices, which are valuable for determining supply planning as well as silvicultural and road building investment decisions. Chapter 2 - Selective logging is the most common method of timber extraction in native tropical and subtropical forests, including the Atlantic Forest of South America. Uncontrolled conventional logging has resulted in impoverished forests that have lost much of their economical value and biodiversity. In poorly logged forests in sub-tropical Argentina, bamboos colonize felling gaps and inhibit canopy tree regeneration while lianas slow the growth rate of most canopy trees. Reduced impact logging techniques along with post-harvest silvicultural treatments to enhance canopy tree growth and regeneration have been shown to be effective in the Atlantic Forest eco-region, but destructive timber mining practices nevertheless continue.

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Chapter 3 - During the last 20 years, the size of the forest estate in Ireland has increased dramatically. Inventory and management information on the (FSC-certified) publicly-owned forest is widely available, however details on the rapidly expanding private estate, both in terms of inventory data and management objectives, are missing. The developed PractiSFM Decision Support System comprises Microsoft ExcelTM based inventory and decision support components that permit the collection and quantification of data for multiple forest resources and facilitates the production of 10-year sustainable forest management plans. The inventory component consists of a standardised set of protocols for observing, assessing and recording multi-resource forest inventory data at the stand-level scale, based on local measures of Criteria and Indicators identified in the Irish National Forest Standard. This paper describes the PractiSFM DSS, which provides a means to integrate, tabulate, forecast, map and analyse multi-resource inventory data through the use of interactive and visual tools. The DSS can be used to generate planning scenario information at a forest and stand level, such as timber volume/value assortments, area of visually or environmentally sensitive forest, area affected by harvesting operations, changes in deer cover and food habitat, cumulative deadwood volumes, productive man hours and operational cash flow. The outputs from the PractiSFM system have the additional potential to facilitate the standardisation of management plan reporting and feed into the national forest information system. The system provides practical and efficient tools for the implementation of sustainable forest management, based on the Irish SFM policy initiative. Chapter 4 - Ecological restoration represents an important tool for combating land degradation and increasing ecosystem resistance and resilience to disturbance, thus favoring the recovery of functions and services. Degraded drylands constitute very harsh conditions for the natural regeneration and rangeland restoration of the ecosystems. Scarcity of rainfall after planting, inappropriate seedling quality and unfavorable hydro-physic and chemical characteristics of the soil often affect the success of ecological restoration projects. Therefore, there is a need to improve ecological restoration techniques in degraded drylands. In this paper the authors analyze innovative nursery and field techniques oriented to reduce outplanting stress on the basis of the researcher experience of the CEAM Foundation‘s Forest Restoration Programme and the Ecosystems Management and Biodiversity group in the University of Alicante‘s Department of Ecology though several RTD projects funded by the Valencia Regional Government, the Government of Spain and the European Commission. In the nursery, the main research lines are directed towards improving seedling quality, especially its resistance to water stress, by means of the use of containers gauged to the different root growth patterns of the species, the use of hydrogel to improve the water holding capacity of the substrate and reduce post-planting stress, the use of drought preconditioning to induce mechanisms for drought resistance, the use of fertilization according to field conditions and target seedlings for restoration projects and the use of growth regulators to control the biomass distribution within the seedlings. Other research lines are focused on ameliorating site conditions in the field, particularly soil and microclimatic conditions, by using: microcatchments to improve runoff harvesting and soil water availability to seedlings, deeper planting holes according to species growth patterns, treeshelters to reduce environmental stress, hydrogels to improve soil water-holding capacity, organic amendments like biosolids to improve soil fertility, and biotic interactions to facilitate seedling establishment. Then, the authors present the demonstration project on the restoration and management of semi-arid areas affected by desertification in Albatera (Spain) as an example

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of the implementation of these innovative techniques. This project has shown that increased technological investment in forest restoration ensures acceptable results in seedling survival and growth, and gradual ecosystem recovery. Finally, the challenges and opportunities for ecological restoration in dryland are discussed on the basis of the results shown and future climate projections. Chapter 5 - The authors used ecological niche modeling and place prioritization procedures to identify areas for conservation and restoration for the river otter, Lontra longicaudis annectens Major 1897, in central Mexico. This species is highly sensible to fluvial ecosystem degradation, and large areas of the Apatlaco-Tembembe basin fluvial ecosystems have been highly transformed. The authors selected ecological indicators (EI) from literature and own field work to determine variables best describing the fluvial ecosystem degradation, relating them to the species‘ presence or absence. Field data of EI, species records, and digital thematic information of hydrology, geomorphology and climate were used in ResNet Place Prioritization algorithm for the selection of potential conservation and restoration areas. The authors generated a spatial model considering a hierarchy of key areas based on river otter‘s ecological niche requirements and habitat ad hoc conditions for the species permanence. This allowed identifying areas to be included in landscape management plans for conservation and restoration. The sequential integration of species´ potential distribution and place prioritization modeling allows merging biodiversity conservation and ecological restoration strategies at different ecological scales, helping adaptive management in land planning to be more flexible and feasible. Chapter 6 - Caatinga is the typical semi-arid native forest of the Brazilian northeast covering still about 40% of the total of 850.103 km2. Due to high pressure for forest fuels and forage, sustainable forest management would be the most indicated alternative as reforestation potentialities are limited. From the other hand, global awareness and worries urge for efficient biodiversity conservation at different levels. This case study evaluates tree growth and biodiversity dynamics in two commercial forest management plans (350 hectares each) in order to assess production capacity on one hand, and the contribution of forest management to biodiversity conservation on the other. Forest inventory in a total of 53 plots in different age stands allowed evaluating growth rates and tree diversity along several stages of caatinga regeneration. Growth rates were very high in young stands and MAI ranged from 4.5 – 5.1 m3.ha-1.a-1. Original biomass, at this rate, can be recovered in about 10 years. However, forest structure, expressed by volume distribution per diameter class, is recovered more slowly, being necessary 15 to 20 years or more. These results indicate that native forest management can be an excellent means for supplying the wood fuel needs of the region. Biodiversity studies considered different biological groups: trees, herbaceous plants, native bees, mammals, amphibians and reptiles. Caatinga forest management did not cause loss of tree diversity. Original dominant species maintain dominance in the regeneration stands and new species occur. Herbaceous plant diversity was similar to the one in preserved areas despite lower Shannon values. The initial impact of forest management on the native bees was strong but after 9-14 years, original diversity is mainly recovered. Apparently, diversity of amphibians and reptiles depends more on habitat diversity than on the management activities. Total diversity found in the commercial managed areas was similar or higher than the one in preserved areas.

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Resources available in the several aged stands differ and offer distinct living conditions for the native fauna (food, shelter, reproduction). Mammals were found to be a group inadequate to study impact of forest management as interfered areas are relatively small (< 500 ha). It may be concluded that commercial forest management plans, including also 20% of legally preserved areas, offer an excellent environment for biodiversity conservation integrated with sustainable forest production. Chapter 7 - Protected areas are usually perceived as natural places devoid of human presence, where nature is let to unfold its developmental potential. Indeed, this is the dominant representation even for timber-dependent areas. Modern notions, which occupy a crucial position in the dominant environmentalist discourse, such as the catch term ‗biodiversity‘, often perpetuate this supposed divide between society and nature. Within the frame of this paper, the authors will see how forest management in a Greek protected area helped an endangered vulture species recover and surpass viable population sizes. The case study to be presented wishes to elucidate the delicate way in which societal choices are interwoven with dynamics of natural systems in determining outcomes for both the social and the natural realm. The authors will focus on the Dadia Forest reserve, situated at the northeastern part of Greece, which has been most known for hosting a remarkable variety of raptor species, including three European vultures. The zoning system that has been implemented since the designation of the protected area in 1980 aimed at the preservation of the nesting and feeding habitat of vulture species. The Allee effect, which is expected to mediate population dynamics of raptor species, including vultures, is connected to both an unstable and a stable equilibrium threshold for population dynamics of vulture species. Through zoning and specialized forest management, the environmental protection regime gradually led to the confinement of individuals of vulture species to the core compartments of the protected area, which actually was a milestone in the reconfiguration of vulture population sizes from unstable towards stable equilibria. Three decades after the Dadia Forest Reserve has been established, local attitudes towards environmental conservation have changed dramatically, together with land-use patterns and vulture numbers. Locals no longer resist environmental management initiatives but are proud of their area being among the most famous ecotourism destinations in Greece. Visitors come to Dadia to observe from a Bird Observatory vultures feeding on carcasses on the Vulture Feeding Table, which has been landscaped in the protected area to provide food supplement to vultures. Indeed, many residents are employed in conservation or ecotourism related jobs. Interestingly, the population size of the Black Vulture, an endangered vulture species in Europe found formerly only in Dadia and the region of Extremadura in Spain, seems to have exceeded the carrying capacity of the Dadia forest; a number of individuals migrated recently to neighbouring forested sites of Bulgaria. Chapter 8 - Decision-making regarding sustainable forest resource allocation and protection requires suitable and comparable information on the state of forest resources and the human use of forests. It is here that sustainability assessment has become a recognized approach to better informing decision makers on the social, economic and environmental dimensions of forest management. This chapter compares macro-level forest resource statistics in 24 jurisdictions of North America and Europe to enable the implications of resource variability to be considered and discussed in the context of sustainability assessment. The results highlight certain similarities and differences at the macro-level of forest management in each jurisdiction that will affect the nature of sustainability assessment at the

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regional, sub-regional and nation/state/province levels. These differences will affect management goals, sustainability indicator selection and the subsequent scale and intensity of monitoring and reporting required to ensure informed decision-making. They will also affect the level of public sector investment in monitoring, assessment and performance reporting to the community, resulting in variability in forestry-related data quality and quantity in different jurisdictions. Despite this, increasing globalization and internationalization has precipitated a demand for standardization and comparability of sustainability indicators and associated sustainability assessments between jurisdictions. There is, therefore, a need for researchers to build on the issues presented in this chapter by further considering how forest resource-related monitoring and information reporting in different jurisdictions differ; and what the implications are for assessing sustainable forest management at an interjurisdictional level. Chapter 9 - Afforestation activities in Israel take place over an extreme geobotanical and climatic gradient of between 250-900mm of rainfall a year. A relatively moist, Mediterranean climate, natural woodlands of evergreen, sclerophyllous oaks and planted forests of Mediterranean pines and cypresses characterize the vast majority of forestlands in northern Israel. In contrast, an eastern semi-arid pocket associated with the Syrian-African Rift Valley presents challenging environmental conditions for afforestation efforts as practiced by the British Mandatory Forest Department, the Israeli Governmental Forest Department, the Keren Kayemeth Leisrael (KKL) and private entrepreneurs over the past 80 years. The accumulated experiences of planting new forests in this semi-arid zone, combined with results from introduction plots and afforestation areas throughout Israel, led to the development of a unique set of silvicultural tools and tree species employed to guarantee successful afforestation plans. All of these new afforestations function as multipurpose forestry systems offering landscape, watershed, soil conservation, pasture, recreational and NWFP goods and services and can provide a relevant model of sustainable forest management for semi-arid and arid zones worldwide. Chapter 10 - In arid region in Tunisia, olive tree (Olea europaea L.) is the most extended crop in the area, not only for its socio-economic importance and the benefits of olive oil, but also for its tolerance to contrasting environmental conditions (high temperature, low precipitations, high photosynthetic photon flux density, water and salt stresses) and its great role in the preservation of the green area landscape, the prevention of soil erosion, land degradation, and thus the maintenance of land durability. Olive tree is a biannual species whose biological cycle proceeds in two years. During the first crop season, they are the vegetative processes (leaf expansion, shoot elongation) who dominate. In the second one, the reproductive processes (flowering, pit hardening, fruit development, ripening) start in December-January with the floral induction which is dependent on the achievement of pollination. Although, it is considered as a thermophile species, both of the olive growth phases are determined by ambient temperature and an optimal temperature was determined for each growth (vegetative and reproductive) step. For the Chemlali olive, a temperature comprised between 10 and 12°C is essential for vegetative growth start. The flowering is optimal at a temperature of 18 - 20°C. However, a temperature of 21 - 22°C is optimal for pollination. At 32°C, the growth is slow down and it is stopped at 35°C even under well water availability. Sometimes, under particular climatic circumstances, fruit ripening can extend to the beginning of the third crop season. The olive growth is dependent on both climatic (air temperature, atmospheric humidity, plant water status,

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photosynthetic photons flux density, wind speed,….) and edaphic (soil texture and permeability, pH, soil fertility,….) conditions. Under climatic conditions of the south of Tunisia, olive vegetative growth cycle is characterized by four phases: two vegetative growth and two plant rest phases. The vegetative growth phases are divided, in their turn, in two types: (i) The intense vegetative growth (IVGP) and (ii) the partial vegetative growth phases (PVGP). The plant rest phases occurred in two distinct periods. The first rest phase happening in summer period is known as ―summer rest phase SRP‖ and the second one occurred in winter (winter rest phase, WRP). The intense vegetative growth phase and the partial one take places in spring and autumn period, respectively under favourable climatic conditions (air temperature, humidity, and photosynthetic photons flux density). As well, they are the environmental conditions who determine the olive growth stage. The rest phases were adapted by the olive tree in order to avoid its damaging survival mechanisms under high temperature occurring in summer (SRP) and / or low temperature period (cold) occurring in winter (WRP). The examination of the olive biological cycle shows that its activity is concentrated in time and both vegetative and reproductive growth phases occurred in some parts simultaneously. This coincidence could lead to the establishment of a nutritional competition between the different developed tissues along the phenologic stages. Under contrasting environmental conditions, the arid active species (olive) developed special survival mechanisms. These adaptive strategies allow the photosynthetic performances to be accomplished during a long period of the year, even in low rates. Per consequent, olive is characterized by a high growth rate, which leads to an important tree canopy, in comparison to some others fruit trees (peach, apple, grapevine,….). Besides, it was observed that olive growth response to different environmental constraints depends on its vegetative growth phase. Olive growth is more sensitive to abiotic stresses during the intense growth phase than during the rest one. Short Communication A - When a landowner considers the management of an even-aged stand of trees, along with decisions related to intermediate silvicultural treatments, the rotation age decision is of importance. An even-aged rotation is the length of time between the establishment of a stand of trees and the clearcut or final harvest of the trees. A number of qualitative and quantitative methods can be used to arrive at the desired rotation age of an even-aged stand of trees. This chapter describes seven rotation age determination processes: the physical rotation age, the technical rotation age, the silvicultural rotation age, the maximum volume rotation age, the income generation rotation age, the economic rotation age, and the value growth rotation age. Each rotation age determination process may be valid for a given landowner and their objectives, therefore the processes are approached from a relatively objective point of view. Examples pertaining to a pine forest from the southern United States are presented to compare and contrast the rotation age determined using each process. Short Communication B - In forest management, there are three important questions to consider: (1) What are the objectives that management activities hope to achieve? (2) What are the operational procedures and financial resources required in executing a scheduled action plan for achieving the objectives? (3) What are the criteria that may be used for assessing the extent to which the objectives are obtained and for evaluating the cost effectiveness of the operations? Essentially, forest managers are primarily concerned with

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setting appropriate targets, taking necessary steps to reach the targets, and measuring the level of success in accomplishing the targets.

In: Forest Management Editor: Steven P. Grossberg

ISBN: 978-1-60692-504-1 © 2009 Nova Science Publishers, Inc.

Chapter 1

A DECOMPOSITION APPROACH TO INTEGRATED FOREST HARVEST SCHEDULING AND ACCESS PLANNING David M. Nanang 1* and Grant K. Hauer*2 1

Natural Resources Canada; 1219 Queen Street East, Sault Ste Marie, Ontario, Canada, P6A 2E5 2 Department of Rural Economy; University of Alberta; Edmonton, Alberta; Canada T6G 2H1

ABSTRACT This chapter presents the results of a mixed-integer non-linear programming (MINLP) model that integrates access road development with forest harvest scheduling. A Model II forest scheduling model that maximized net present value of timber products subject to mill capacity, multiple mill and product demands, regeneration, area, and access constraints was specified. The model was applied to an operationally-sized Forest Management Agreement (FMA) area in central Alberta, Canada. The resulting model had approximately 2.6 million decision variables and about 96,000 constraints, and was used to examine the impacts of access development on harvest scheduling. The results show that the inclusion of road access costs concentrated forest management activities to fewer locations over the planning period compared to when road construction costs were zero. Also, positive access costs reduced the frequency with which locations are accessed during the planning horizon. The model provides important shadow price information on the various constraints in the model that gives insights into future production costs or timber prices, which are valuable for determining supply planning as well as silvicultural and road building investment decisions.

Keywords: Access costs; forest management scheduling; dual variables; optimization techniques.

*

David M. Nanang: Phone: (705)-541-5562 ; Fax: (705)-541-5704 ; Email: [email protected]; or [email protected] * Grant K. Hauer : Telephone: (780) 492-0820; Fax: (780) 492-0268; Email: [email protected]

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INTRODUCTION The construction of access roads and the determination of efficient access paths within a forest are central issues in long-term forest management planning for several reasons. First, due to the substantial capital investments required in roads, a large fraction of total forest management costs is spent on road construction or upgrading. Secondly, adequate access must be provided before management activities can be carried out in forests (Weintraub and Navon, 1976). Incorporating access in strategic forest planning models is also important because of the cumulative effects of access provision on non-timber values in the forest. For example, the level of access within a forest may affect the welfare of hunters and recreationists (e. g., McLeod et al., 1993; Adamowicz et al., 1997). Consequently, forest managers and researchers are interested in formulating and developing solution techniques for forest management planning problems that incorporate access. A wide variety of optimization models have been used in forest planning to analyze separately silvicultural and transportation problems (Bare, 1972). In this method, road building and timber management are planned separately, that is, road planning and/or construction usually precede harvest planning. Stands are thereafter scheduled for harvesting based on their accessibility. Weintraub and Navon (1976), however, argue that this sequential nonintegrated approach can lead to sub-optimization on two counts. First, the wrong set of stands may be made accessible; and secondly, the choice of the period of access to each stand may not be optimal. Based on these two reasons, discounted costs of construction, maintenance and hauling may be higher than absolutely necessary, and the impossibility of carrying out silvicultural treatments at the appropriate time may reduce gross timber revenues. When access road construction plays an important role, a more accurate way of dealing with this problem is to represent explicitly in the same model both access and timber resources management activities. Weintraub and Navon (1976) and other earlier studies that integrated road network into timber scheduling e. g., Kirby (1973), Barnes and Sullivan (1980), Sullivan (1973) used mixed integer programming (MIP) for planning the development and use of transportation network. Simultaneous optimization of forest management activities and access using MIP is easy to solve for small models. However, the difficulty of solving such models increases as the number of decision variables and constraints increase. Although these previous problems were of practical sizes for solutions on computers they were not realistic in a practical sense given the reality of forest management on the ground. Whilst the formulations of mixed integer problems that address stand level and access decisions are not difficult in principle, the main disadvantage is that these problems cannot be solved in a reasonable amount of time because of the integer restrictions. To overcome this, more recent studies have relied on heuristic-based approaches. The major drawback of these approaches is that they do not lend themselves to intertemporally optimized harvest schedules nor do they provide the shadow price information on any of the constraints incorporated in the formulation. Furthermore, most of these models focus on logging access at the operational level, rather than the strategic level of planning. This chapter addresses these shortcomings by developing a mixed-integer non-linear programming (MINLP) model that integrates access road development with forest harvest scheduling. We apply the model to an operationally sized timber management problem in

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Alberta, Canada. The main objectives were to: 1) develop a model that integrates access planning into a large, spatially detailed strategic forest scheduling model, and 2) examine the effects of explicitly including access development costs on the harvests schedule and road development. The solution technique of this model is based on an extension of the dual decomposition approach introduced by Hoganson and Rose (1984). The extension incorporates mixed integer programming and uses the theory of lagrangian relaxation discussed by Geoffrion (1974) and Fisher (1981, 1985). While the timber supply model is formulated for a real land base on a Forest Management Agreement (FMA) area in Drayton Valley, Alberta, we have modified mill demands slightly. The forest management model described here incorporates multiple products, multiple supply locations, and silvicultural investments in forestry and access road construction. Access to timber supply locations is represented by 0-1 variables, leading to a mixed integer problem. The resulting formulation allows for alternative access directions to each location and the intertemporal optimization of road access decisions. The number of integer decision variables in this formulation is estimated at 3850, which in a branch and bound algorithm would have 23850 combinations of solutions although the number of combinations that actually need to be explored is somewhat less than this because of the constraints on sequencing. For example, some locations would have to be accessed through other locations. Even then, it is obvious that the enormous number of feasible solutions associated with this problem will make it an extremely difficult problem to solve using the branch and bound technique. The solution algorithm we employ breaks down the large MINLP problem into simple stand level economic analysis over the planning horizon, and simple optimal path network analysis for access planning in each planning period given the value of current dual prices. Simple intuitive price adjustment procedures are used to change dual prices to move the solution towards feasibility. The application of this approach to modeling harvest scheduling and access in this paper is unique in a number of ways. First, it attempts to optimize forest management activities and road access decisions simultaneously, while satisfying multiple mill demands. As far as we know, most previous studies that have solved the access problem either with MIP or using heuristics have not incorporated the important fact that wood will be transported on these access roads to satisfy mill demands in different locations and with different products. The solution to our model is optimal but near feasible in that mill demand constraints are allowed to deviate from timber supply in each period by at most 3%. Secondly, the model converged within a reasonably short period of computer time (20 minutes on a microcomputer with a Pentium III 500 Mhz microprocessor), which is remarkable, given the large size of the model. The flexibility inherent in our modeling approach allows the path of minimum cost to be determined endogenously within the level of detail that road access is modeled. Finally, the approach, which is consistent with economic theory, allows us to estimate the shadow prices on all demand and access constraints. These shadow prices provide useful information about the costs of production or future timber prices. The shadow prices on the demand constraints represent the marginal costs of producing the outputs from the demand centers, whilst the shadow prices on access constraints indicate the average road construction costs per cubic meter of timber harvested from the stands over time. The shadow price information is valuable for supply planning and current planning in silvicultural and access road investment expenditures.

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The rest of the Chapter is organized as follows. The next section provides a justification for incorporating access into strategic planning. This is followed by a brief background of previous forest harvest scheduling studies incorporating access. A detailed description of the forest management problem is then presented. The methods section describes the non-linear programming formulation, and the solution method. The results from an empirical application of the model is then provided, followed by a discussion of the management applications of the results, and possible extensions of the present model. The conclusions from the results are presented in the last section.

IMPORTANCE OF STRATEGIC ROAD PLANNING Traditionally forest planning is divided into a hierarchy of planning phases depending on whether it is long or short term – strategic, tactical, and operational. Strategic planning is conducted to make decisions about sustainable harvest levels while taking into account legislation and other regulatory requirements. Within the frame of the strategic plan, the tactical plan schedules harvest operations to specific areas in the immediate few years and on a finer time scale than in the strategic plan. The operative phase focuses on scheduling harvest crews on a monthly or weekly basis (Andersson, 2005). Most strategic forest planning does not include access road development. It has often been argued that due to the long planning horizon envisaged in strategic plans and the fact that most strategic plans are aspatial, access roads are better considered at the tactical and operational levels of planning. It is true that the long time periods and high degree of uncertainty associated with strategic road plans means that the roads will not necessarily be implemented exactly as planned. Therefore the operational feasibility of the projected road network is not the main concern (Anderson, 2005). Despite these apparent shortcomings, incorporating access development into strategic plans still plays a vital role in forest management planning. At the strategic level, the framework of the roads is the most important concern as it guides the development of the forest (Anderson, 2005). The strategic planning process determines all logical harvest and transportation options and provides a tool for the efficient investigation of these options in the field. Feasible options must be safe, productive, economical, and meet environmental constraints. Strategic plans allow the identification of specific roads meeting certain standards. Roads can be budgeted and built according to present and future needs (Aulerich, 1999). In the strategic planning phase, areas to be reserved for biodiversity conservation, watercourse protection or community land-use needs are identified. Because forest regeneration takes several decades, strategic road planning also ensures that sustainability, mill demands, and economic profitability criteria are met through adequate regeneration and the future harvest areas and schedule for harvesting each identified area have the required road locations and standards.

A Decomposition Approach to Integrated Forest Harvest Scheduling…

5

LITERATURE REVIEW Kirby (1973) was probably the first to recognize the advantages of jointly modeling forestry activities with their required road network. Kirby‘s paper offered the stimulus in the US Forest Service to re-examine the long-standing sequential planning of roads and management activities. The model was a mixed integer program, which was formulated to maximize benefit from forestland less costs (including road construction costs), subject to management constraints, and relations between adjacent roads. This model however, did not account for transportation costs. To account for both road construction and transportation costs, Barnes and Sullivan (1980) and Sullivan (1973) developed a MIP model for forest network planning to maximize net revenue (timber revenue net of road construction and transportation costs). In order to keep the MIP problem to a manageable size, Barnes and Sullivan (1980) generated K-shortest paths between each timber sale and demand points. Optimization was therefore restricted to these paths, which was a small select number of all possible paths. Weintraub and Navon (1976) combined the network analysis scheme of Sullivan (1973) and proposed an integrated approach, which was applied to a hypothetical forest, covering an area of 100,000 acres. The resulting mixed integer-programming model had 118 timber management activities, with 215 constraints and 256 variables, 24 of which were 0-1 integer variables corresponding to building road segments. The results from the example showed that by jointly considering transportation and timber management, an increase in discounted net revenue of 7% was achieved, 6% of which was from savings in road building and fixed maintenance costs. Their model considered only one demand location and no differentiation of forest products. Also, both the area and the number of activity variables and constraints were relatively small. The network was also simplified by approximating the road network by a hypothetical one consisting of only major corridors. It was realized in practice that for large and complex networks, optimization based on paths consumes much analyst‘s time in manually adding paths and may lead to poor solutions as well (Kirby et al., 1986). This is a result of the fact that road construction costs are not used in generating shortest paths. There was no simple way of incorporating road construction costs for each path since many other paths may share a portion of this cost. Kirby et al. (1979) overcame this difficulty by considering all paths using the classical transshipment formulation. Whilst the formulations of mixed integer problems that address stand level and access decisions are not difficult in principle, the main disadvantage is that these problems cannot be solved in a reasonable amount of time because of the integer restrictions. To overcome this, more recent studies have relied on heuristic-based approaches. One of the early applications of such heuristic-based methods is that by Bullard et al. (1985), who modeled forest scheduling using random search algorithms. O‘Hara et al. (1989) also developed randomized search heuristics, which pre-biased the selection of stands based on volume and adjacency. However, because this study used a volume maximization objective function, transportation and road construction costs were not considered, although the model performed well compared to the optimal linear programming (LP) solution. In order to correctly represent the costs of road and transportation, Nelson and Brodie (1990) developed a random search heuristic that maximized present value minus road construction costs in the objective

6

David M. Nanang and Grant K. Hauer

function. Other studies that used simple heuristics are those of Clements et al. (1990), Walters (1991), and Nelson and Finn (1991). Another heuristics approach that has been used to solve large forest scheduling problems is the simulated annealing algorithm that was presented by Kirkpatrick (1983). This method has also been applied by Lockwood and Moore (1993), using penalty costs to ensure that volume and adjacency constraints are met. This study and others by Dahlin and Sallnas (1993) showed that the simulated annealing approach is a viable method to solving large problems. Murray and Church (1995) compare the simulated annealing method to the Tabu search and pairwise interchange approaches and concluded that the Tabu search performed best. A more recent three-stage heuristic for solving harvest scheduling with access road network is reported by Clark et al. (2000). The procedure was shown to work well within a very short computer time; however, the application was for a small forest of about 3600 ha. The performance of the model for large problems remains untested and no particular demand locations were identified and included in the model. Recently, Epstein et al. (2006) developed a model that consists of finding a design that will minimize the cost of installation and operation of harvest machinery, road construction, and timber transport, while complying with the technical restrictions that apply to the operation of harvesting equipment and road construction. The network design was modeled as a mixed-integer linear programming problem. The model was fed with cartographic information, provided by a geographic information system (GIS), along with technical and economic parameters determined by the planner. A specialized heuristic was developed to obtain solutions that enable harvesting economically profitable volumes at a low cost.

METHODS Model Formulation To illustrate the usefulness of our modeling approach in providing meaningful information in a realistic setting, a mixed integer non-linear programming formulation was used to develop the timber management schedule for a Forest Management Agreement (FMA) area in Drayton Valley, Alberta. The model is an extension of the Model II structure formalized by Johnson and Scheurman (1977). The problem being addressed in this study can be described as using optimization techniques to formulate and solve an integrated forest scheduling and access road construction activities. Using spatial data from geographic information system, the forest area was aggregated into 577 locations, each location being one-ninth of a township or about 1111 ha (one township 10,000 ha or 100 km2). The problem therefore, is to maximize the present value of wood scheduled on these locations less harvest, transportation, regeneration, and road building costs. With regards to road construction, we define locations that currently have a major road through them as permanently opened/accessed locations (POLs). These POLs are assumed to be built and maintained in good condition throughout the planning horizon at some fixed cost. Temporary or intermittent roads are built to each location in each planning period as needed. To reduce the problem to a reasonable level of complexity, we did not explicitly model temporary roads built to access stands within locations. We find the cost-minimizing road network to connect all locations targeted for harvests to the existing roads. Locations to be harvested are

A Decomposition Approach to Integrated Forest Harvest Scheduling…

7

determined based on economic criteria of timber benefits of accessing a location exceeding the costs of doing so. We originally considered a formulation similar to Sullivan‘s (1973) Kshortest paths method which restricted optimization to the few selected paths but abandoned it in favor of a more flexible approach. Although the model does not identify the exact location of roads, it however suggests access directions and access timings along corridors in the range of 1/9 of a township. This could, however, be extended to a smaller spatial unit if necessary. The present formulation allows for differential road construction costs to be easily incorporated, although we did not do this here. Also, at the moment the optimal paths are decided purely on the basis of timber value, but non-timber values could be included as in Nanang and Hauer (2008). The mixed integer, non-linear programming formulation for this timber supply problem is given by Equations 1-11. First, we define the following sets and variables: Let J be the set of all supply locations in the forest with j serving as a counter (j=1,…,J ). J P be the set of permanently accessed supply locations. J 1 be the set of all permanently accessed locations that are adjacent to at least one location that is not accessed. I be the set of all demand locations with i serving as a counter (i=1,…,I)

I jA be the set of all supply locations adjacent to j from which product may be shipped. This set is empty for all j

J

p

J 1 . (that is, permanently opened locations that are not

adjacent to any unaccessed locations).

I Bj be the set of all supply locations adjacent to j to which product may be shipped.

I Cj be the set of all demand locations to which product may be shipped from j. This set is empty for all j

J p.

p be the volume shipped from supply location j to demand location i for j y jit

J p.

y Ajkt be the volume shipped from supply location j to supply location k for

j

Jp

J1 and k

Jp.

y sjt be the volume supply at location j. yitd be the volume demand at demand location i.

David M. Nanang and Grant K. Hauer

8

zjt be the 0,1 access variable for location j.

The objective function for the forest management problem is given by Equation 1. T z

R( yitd )

max i

t

T

J

E jt w jt t

j

c Ajt z jt

c stj xstj s

M s s z

j

t

j J

p

p c sjit y jit t

j J

p

s A c kjt y kjt t

p

j J k I

A j

(1)

i

subject to: T z

y sjt

A ykjt

vsjt xsjt T0

s

yitd

A

for j

j, t ( I j

J

p

J1)

(2)

k I jA

p y jit

i, t

y sjt

j

J

p

(4)

y sjt

j

J

p

(5)

y sjt z jt

j

J

p

(6)

(3)

j JP

y Ajkt k

I Bj p y jit

i I cj

y sjt t z

T

xsjt T0

s

xtkj

w jt

j, t

0,...., T

(7)

k t z

T

xsjt

w jt

Asj

j, s

T 0 ,....,0

(8)

t s z

xsjt

0

sjt

(9)

wsj

0

sj

(10)

yitd

0

t

(11)

The remaining variables used are defined as:

R( yitd ) = the revenue for wood products at demand center i in period t. Esj = the discounted value per unit area of managing stand type j starting in period s and leaving the stand type as ending inventory wjt = area managed of stand type j in period t and left as ending inventory xsjt = area managed on stand type j in period s and final harvest in period t

A Decomposition Approach to Integrated Forest Harvest Scheduling…

9

The parameters are defined as:

c Ajt = discounted cost of accessing (road construction) location j in period t s = discounted cost/m3 of shipping wood from location k to j in period t c kjt

c sjit = discounted cost/m3 of shipping wood from permanently accessed location j to demand center i in period t Asj = the number of area unit of stand type j in the first period that were regenerated in period s. csjt = the discounted cost per unit area of managing stand type j starting in period s and final harvest in period t vsjt = the merchantable volume per unit in period t, when stand type j is regenerated in period s. z = minimum time between regeneration and harvest T = the number of planning periods in the planning horizon T0 = number of periods before period zero in which the oldest age class present in period one was regenerated The first equation of the model, Equation 1, is the objective function, which maximises the net present value of the forest. This is represented as the discounted revenue from the sale of final wood products plus the value of ending inventory minus the cost of regeneration and harvesting, road construction costs, costs of shipping wood from one location to an adjacent location, and the cost of shipping wood from a permanently accessed location to the demand center (mills). Equations 2 and 3 describe the timber supply and demand system. Equation set (2) says that the volume supply of wood in a given location j at time t is the sum of wood supplied from that location plus any wood that is shipped through that location. The second term on the right hand side of Equation 2 is only relevant for areas that are not permanently accessed and for areas that are permanently accessed but immediately adjacent to areas that are not accessed permanently. Equation (3) is quite straightforward and imposes bounds on the timber flow to mills. These ensure that the wood shipped from permanently accessed locations to the mills is not less than the mill demands. This constraint is only relevant to permanently accessed locations because wood cannot flow from non-permanently accessed locations directly to the mill. All wood flow to the mills has to go through permanently accessed locations. Equations 4 to 6 define the access and wood transport from one supply location to another supply location and from supply locations to mills. Equation 4 is only relevant for areas that are not permanently accessed. Equation 4 is an accounting equation that measures the volume of wood supply in locations. Specifically, it states that the volume of wood shipped from one location to another location cannot be greater than the volume supply of wood in the initial location. Equation 5 implies that the volume of wood shipped from a permanently accessed location to a mill cannot be greater than the volume supply of wood in the supply location. Equations 4 and 5 taken together suggest that wood flows from one location to another in the locations that are not permanently accessed, whilst in permanently accessed locations, wood is shipped directly from supply locations to the mills. Equation 6

David M. Nanang and Grant K. Hauer

10

constrains the model to ensure that each location without permanent access is accessible when it is to be harvested. That is, wood cannot flow from an unaccessed location, which implies access must first be provided before any location can be treated or harvested. It is important to notice that Equation 6 is quite different from the rest in that it is a non-linear constraint in which the access variable (zjt) is a binary integer variable. This equation could also be written as y sjt

z jt M , where M is a large number. This is the standard way of writing such a

constraint. However, here we use the form in Equation (6) due to the fact that we applied the dual decomposition approach that uses heuristics to adjust dual prices on constraints. We find that the constraint as written in Equation (6) provides a more convenient interpretation of the dual price and heuristics for price adjustment. Equations 7 and 8 describe the forestland constraints including the initial age class distribution and the dynamics of transition from harvest to regenerated stands. These two equations are part of the standard Model II set-up of Johnson and Scheurman (1977). Equation 7 accounts for area regenerated during the planning period. Total area harvested during the planning period plus area left as ending inventory at the end of the planning period should equal area regenerated during the planning period. This constraint ensures that all harvested areas are regenerated. Equation 8 defines the total area availability for the forest area regenerated before the planning period (existing stands). Total area harvested during the planning horizon plus area left as ending inventory (at the end of the planning horizon) should equal the initial area (regenerated in period s before planning period). We now specify the lagrangian function together with the dual variables for each constraint. These dual variables are important for two main reasons. First, the forestscheduling problem as presented above will be difficult to solve using traditional mixedinteger non-linear programming solution techniques due to its large size (about 2.6 million decision variables and 96 thousand constraints). The simulation approach of Hoganson and Rose (1984), which is used to solve this model, relies on a direct interpretation of the dual problem formed using Equations 1 to 8. Secondly, some additional insights and relationships to other literature are apparent from analysis of the dual, for example the Faustmann (1849) optimal forest rotation model. The lagrangian to the primal problem can be stated as: T z

R( yitd )

L i

t

T

J

E jt w jt t

c Ajt z jt

c stj xstj

j

T0 s s z

s

j

t

j J

s A c kjt ykjt

p

t

j J pk I A j

T z p c sjit y jit t

p

j J

u jt

i

j

t

A ykjt

vsjt xsjt s

T0

v jt y sjt

y sjt

k I jA

j J

p

T jt j J

p

y sjt i I cj

t

0

s

T

jt j J

p

y sjt z jt

y sjt

t z

s jt j

t

k I Bj

t

t 0

T

xsjt s

T0

xtkj

w jt

k t m

T

a sj Asj j

p y jit

A ykjt

0

xsjt t s z

w jt

p y jit

it j

t

i

yitd

I cj

The first order conditions from Equation 12 for the continuous variables are:

(12)

A Decomposition Approach to Integrated Forest Harvest Scheduling…

R' ( yitd )

Ly d it

0

it

Lxsjt

c sjt

u jt vsjt

a sj

s jt

0,

0 if xsjt

0

j, s

Lxsjt

c sjt

u jt vsjt

s sj

s jt

0,

0 if xsjt

0

j, s

Ly A

s c kjt

u jt

vkt

0,

0 if ykjtA

0

Ly A

c sjit

jt

it

0,

p 0 if y jit

0

Lys

u jt

v jt

jt

Lys

u jt

jt

0,

kjt

kjt

jt

jt

11

( z jt 1)

0,..., T and t

J p, j

k

j

J p ,t

0

j

J p ,t

0

Lwjt

E jt

a sj

0;

0 if

w jt

0

s

Lwjt

E jt

s sj

0;

0 if

w jt

0

s

z,...T

I kB , t

J p , i, t

0 if y sjt

0,...T

s

j

0,

0 if y sjt

T 0 ,...,0 and t

T 0 ,......,0

0,......, T

Since zjt takes on integer values, the lagrangian is not differentiable everywhere with respect to zjt. Therefore we use the difference in the lagrangian value over zjt = 0 and zjt =1.

Lz jt

Lz jt

1

where Lz jt

c Ajt

0

and Lz jt

1

0 are

jt

y sjt

0, if z jt

t, j

1

J

p

the values of the lagrangian function if location j is opened and

closed in period t respectively. The first order conditions may be re-arranged as:

a sj

R' ( yitd )

it

u jt vsjt

s jt

s sj jt

(13)

u jt vsjt

y sjt

s jt

j, s

c sjt

c Ajt

t, j

u jt

s c kjt

jt

it

s jit

u jt

v jt

u jt

vkt

T 0 ,...,0 and t

j, s

c sjt

0,..., T and t J

p

J p, j

k

0,...T s

z,...T

(14) (15) (16)

I kB , t

(17)

j

p

J , i, t

(18)

j

J p ,t

(19)

jt

j

J p ,t

(20)

a sj

E jt

s

s sj

E jt

c

jt

( z jt 1)

T 0 ,......,0 s

0,......, T

(21) (22)

12

David M. Nanang and Grant K. Hauer

Economic Interpretation of the First Order Conditions The first equation, Equation 13, implies that marginal revenue of a wood product at the mill equals the price of the product. The right hand side of Equation 14 is the value of the wood at rotation minus the cost of growing plus the value of the next rotation for every rotation t = s+ z,….,T. Equation 14 implies that the dual variable a sj, which is interpreted as the land value of type j if born in period s, is bounded from below by the expression on the right for every t from s+ z to T. This means the land value is at least equal to the rotation t that gives the maximum value. The interpretation of Equation 15 is similar to Equation 14. This condition is interpreted as the value of the wood at rotation minus the cost of growing plus the value of the next rotation for every rotation t = s+ m,….,T. This equation represents a generalization of the simple Faustmann (1849) rotation model. The generalization is that prices may vary over the rotation period and in subsequent rotation periods. Also, this shows how the forest level model links to the simple one stand optimal rotation model. The simple recursive structure of the equations lends itself to solution by backward dynamic programming. Equation 16 provides the criteria to determine whether to access a location or not. This equation means that if the value of wood crossing over the location j in period t is at least equal to the access cost, then the location should be opened. On the other hand if it is less, the location should remain closed in that period. Equations 17 to 20 set out the optimality conditions for i) determining the roadside price of wood for each stand in both permanently accessed areas and unaccessed areas, and ii) determining the optimal path from unaccessed areas onto the existing road network. Equations 17 and 19 deal specifically with unaccessed areas. To interpret Equation 17, we note that vkt is the net value of wood at location k and ukjt is the net value of wood at an adjacent location j. This condition therefore says that the net value of wood at location k is equal to the maximum value over all shipping alternatives from k (that is the value at each adjacent j minus the shipping cost to j). This implies the wood should be moved to the location that gives the highest net value. Equation 18 simply says the value of wood at location j is equal to the mill price minus transportation costs, whilst Equation 19 means the net value of wood at j is equal to the value of wood at j minus the access cost adjustment. The access cost adjustment is the shadow price ( jt ) on the access constraint, which can be interpreted as the average cost/m3 of opening up a closed location. If a location is opened, then the access cost adjustment does not apply. But for closed locations, this average cost has to be subtracted from the value of the wood at location j to give its net value. Equations 17 and 19 form a recursive system of equations that forms the basis for the solution algorithm that determines optimal route of wood flow across unaccessed areas discussed in the next section. Equation 21 means the bareland value of the existing stand for any analysis area is at least as great as its value if left as ending inventory. The meaning of Equation 22 is that the bareland value of the regenerated stand for any analysis area is at least as great as its value if left as ending inventory. The optimal rotation decision resulting from the application of Equations 13 and 14 are similar to the Faustmann rule. However, the optimal timing of harvests in this model is modified by the presence of Equation 16, which modifies the prices to shift the harvest cycle

A Decomposition Approach to Integrated Forest Harvest Scheduling…

13

away from certain periods where there are few adjacent stands (i.e., stands within the same location) being harvested. What Equation 16 essentially does is to impose a penalty for harvesting in periods where little or no other harvesting takes place. This penalty ( jt ) is derived from the fixed cost of access at a location level and from the volume of wood flowing over the location. The optimal harvest rule is modified in the sense that some stands that would have been harvested in period t under a zero cost model ( jt 0 ) will be harvested at a different time if

jt

0 and vice versa. For example, if a stand has few stands nearby that

are close to optimal rotation or that provide large revenue then the chances of it being harvested are reduced because the entire road cost would rest on that stand. In this case, the value of the penalty ( jt ) will be high. On the other hand, a stand that has more stands near the optimal rotation age will tend to have a lower penalty and so has high chances of being harvested. A significant effect of a positive jt is that it will tend to concentrate harvests over the landscape. This implies that trees of marginal value that are located close to high value timber are more likely to be harvested once the location is opened. It is also expected that access costs will act as an incentive for reduced frequency of harvesting in a given location. When access costs are included, the number of times in the planning horizon that the location is harvested should be reduced. Although this model does not include non-timber values, it is important to point out that access may significantly affect these values as well.

Solution Technique We define the number of decision variables and constraints to the access problem using a planning horizon of 100 years with 10 planning periods, a minimum rotation of 40 years, three regeneration prescriptions per stand (natural regeneration, basic, and intensive silviculture), a total of 6,156 stand types, 18,883 analysis areas, and approximately 6 shipping Table 1. Calculation of the number of constraints for the access problem Eqn # 2 3 3 4 5 6 7 8 Total

Constraint type

Constraint calculation

Wood supply through locations Sawmill demand OSB mill demand Wood supply at locations ≥ wood shipped Wood supply from permanent locations to mills Access constraint Area harvested = area regenerated Initial area constraints

577 locations

x10 periods

Number of constraints 5,770

1 sawmill 2 OSB mills 385 locations

x10 periods x10 periods x10 periods

10 20 3,850

192 locations

x10 periods

1,920

385 locations 6156 stand types

x10 periods x10 periods

3,850 61,560

18833 analysis areas

18,833 95,613

David M. Nanang and Grant K. Hauer

14

alternatives for each stand. With these assumptions, the resulting model has approximately 2.6 million decision variables and about 96,000 constraints. Details of the calculations of the number of constraints and decision variables are given in tables 1 and 2. It is important to note that there are 3,850 integer decision variables and the same number of integer constraints in this formulation, which in a branch and bound algorithm would have 23850 combinations of solutions although the number of combinations that actually need to be explored is somewhat less than this because of the constraints on sequencing. Even with today‘s fast computers this will be an extremely difficult problem to solve using the branch and bound technique. Table 2. Calculation of the number of decision variables for the access problem Variable Types

Birth period

Number of periods

Number of shipping alternatives

Number of prescriptions

Number of stand types or analysis areas

Number of decision variables

6 1 10 10

6

1 1

18,833 18,833 385 locations 385 locations

677,988 18,833 3,850 30800

1

(10-4-1)

6

3

6156 stand types

554,040

2

(10-4-2)

6

3

443,232

3

(10-4-3)

6

3

4

(10-4-4)

6

3

5

(10-4-5)

6

3

6156 stand types 6156 stand types 6156 stand types 6156 stand types

6156 stand types

184,680

Initial Stands Harvesting variables Ending inventory Integer Variables Shipping alternatives for non-POLS Regeneration stands

Harvest and regenerati on variables

6 7 8 9 10 Ending inventory Total

0 0 0 0 0 10

8

3

332,424 221,616 110,808

2,578,271

Incorporating access development and constraints complicates model formulation and solution in several ways. First, access constraints impose both temporal and spatial requirements on the model and hence considerably increase the number of decision variables and constraints to be modeled. Secondly, because adequate access must be provided before forest management activities can be carried out in forests, it places constraints on where timber can be harvested in any given period. Thirdly, simultaneous optimization of forest management activities and access using mixed integer programming is easy to solve for small

A Decomposition Approach to Integrated Forest Harvest Scheduling…

15

models. However, the difficulty of solving such models increases as the number of decision variables and constraints increase The model was solved using a variant of the dual decomposition algorithm proposed by Hoganson and Rose (1984). Only the general outline is discussed here. The detailed algorithm for the solution is given in Appendix I. First, using a geographic information systems map of the study area, we defined locations on the map that are currently accessible by major roads (primary and secondary paved roads). These are referred to as permanently opened/accessed locations (POLs) and are considered opened in each time period throughout the planning horizon (figure 1). All other areas are considered closed at the beginning of each model run, and these closed areas are sorted according to how far away they are from the POLs, starting from those locations that are directly adjacent to POLs, those that are one location away, etc. There were 192 POLs (zjt = 1), and 385 closed (zjt = 0) locations at the beginning of each model run. The solution algorithm for this problem described below is based on the first order conditions of the lagrangian function derived above. The algorithm begins by solving each stand level problem using initial guesses at the shadow prices for each forest wide constraint for both POLs and initially closed locations.

Note: Permanent roads that appear disconnected are connected to roads outside of the study area. Figure 1. Initial distribution of permanent access on the landscape.

For all POLs, we determined the price of wood in each location using Equation 18, which implies that the value of wood at location j is equal to the mill price minus transportation costs. That is,

s jt

it

c sjit . The maximum of these

receive wood from which POL.

s jt

determines which mill should

David M. Nanang and Grant K. Hauer

16

To determine the value of wood in the unaccessed locations, we defined sub-destinations on the way to the mills at locations that are permanently accessed and adjacent to areas that are not accessed. Also, each unaccessed location is a subdestination. This means that the subdestinations accumulate volumes not only from harvest within their associated supply locations but also from other locations that ship wood through those subdestinations. To determine the direction in which wood should be shipped between locations, we use the first order condition given by Equation (17). From this equation, vkt

u jt

s we note that vkt c kjt

is the net value of wood at location k and ujt is the net value of wood at location j. This condition therefore says that the net value of wood at location k is equal to the maximum value over all shipping alternatives from k (that is the value at each adjacent j minus the shipping cost to j). This implies the wood should be moved to the location that gives the highest net value. The price of wood in each subdestination was calculated by solving iteratively the dynamic programming formulation given by Equation 23 (which is a combination of Equations 19 and 17)

u jt

max u kt k I Bj

c sjkt

jt

( z jt 1)

(23)

Equation 23 is solved using the algorithm given in Appendix I. Once the prices of wood in the POLs and the initially closed locations (the

jt

' s and u jt ' s ), are estimated, we use

these estimates to solve the stand level management problem given by Equations 14 and 15. These stand level decisions include harvest timing for initial and subsequent harvests, mill destination for each timber type, and regeneration options. After all of the stand level problems are solved, the volume flows implied by the harvest timing and transport options are added up and compared to the demand constraint levels. If the flows deviate from the constraint levels and mill demand levels then the shadow prices are adjusted using simple intuitive shadow price adjustment procedures described by Hoganson and Rose (1984) and modified by Hauer (1993). At an optimal solution jt from Equation 16 must satisfy jt c Ajt / y sjt . The right hand side of this equation represents a lower bound on

jt

if an area is opened. If

jt

is

less than c Ajt / y sjt , then an area cannot be opened. The interpretation of the dual variable jt

, given Equation 16, represents the net value of wood per cubic meter (net of transport

and harvest costs). If the net value per cubic meter is greater than the access cost per cubic meter then it makes sense to ship wood over the location. The shadow prices on the access constraints are adjusted based on Equation 5, which is given as: y sjt y sjt z jt . This equation basically states that wood cannot be harvested from or transported through an unaccessed location. Therefore, after solving the stand level problems, the algorithm checks all locations and calculates a deviation for the constraint as

dev jt

y sjt

y sjt z jt . The deviation is either positive or zero. A positive deviation means

that wood is harvested from or transported through a location that is not accessed ( z jt

0 ).

A Decomposition Approach to Integrated Forest Harvest Scheduling…

17

In this case, the shadow price on the constraint is adjusted upward for that location in the next

y sjt

iteration. That is, for dev jt

y sjt z jt

0,

1 jt

0 jt

, f g (dev jt ) , where

jt

is the

shadow price on the access constraint. The function fg is piecewise linear (figure 2) which gives price adjustments as a function of the deviation ( dev jt ). The function gives small price changes for large deviations and large price changes for small deviations. This is because the areas that have lots of wood flowing over them need smaller

jt

to justify transport of wood

over them.

Figure 2. The relationship between the deviations and price adjustments for the access constraint for deviations greater than zero.

y sjt

If the dev jt 1 jt

0 jt

f

opened its

jt

0

c Ajt y

s jt

y sjt z jt 0 jt

0, y sjt

0, z jt

1, then the price changes are based on

. The deviation is always negative since for the place to be

must be greater than c Ajt / y sjt

. The shape of f0 is shown in figure 3.

Figure 3. Shape of the price adjustment function for opened locations and zero deviations.

David M. Nanang and Grant K. Hauer

18

The price changes are large if the difference between the and the previous iteration,

c Ajt y

0 jt

s jt

jt

in a particular iteration

, is large, and vice versa.

After the price changes, we update the database of opened and closed locations. The decision as to whether to open a location or not is based on Equation 16 if jt y sjt c Ajt then z jt

1 . On the other hand, if

jt

y sjt

c Ajt then zjt = 0. This means that if the value of wood

crossing over the location j in period t is at least equal to the access cost, then the location should be opened. Otherwise, the location should remain closed. This process continues until the demand and access constraints are satisfied with a reasonable tolerance. The result of this process defines continuous roads for transporting wood from each location to the mill that maximizes the net present value. This is consistent with a minimum cost path for constructing and transporting the wood from each location to the mills at Drayton Valley.

RESULTS Model Performance The program for the two model runs described in this paper was coded in C and implemented on a personal computer with a Pentium III 500 Mhz microprocessor. The first model is called the Baserun, in which the access costs are computed as an average and then added to the marginal harvesting costs at the stand level. What this means is that one can access a stand anywhere without explicitly building an access route. The second run is called the Access Model, and includes a fixed cost of constructing a road from one location to the next adjacent location of $20,000. This amount was determined based on estimates of the average road construction cost per cubic meter of wood harvested in the FMA. Therefore the Access Model means that no location within the unaccessed portion of the forest can be assessed without first building an access route. The cost of accessing stands within locations was added as an additional harvest cost. In both models, there are two demand centers (a sawmill and an oriented strand board (OSB) mill) both located at Drayton Valley. The maximum demand of final product at the sawmill and OSB mill are 90,000m3/year and 200,000m3/year respectively, with maximum price/m3 of final product set at $300 for lumber and $100 for OSB. These maximum price levels were set based on current estimates of the prices of lumber and OSB. Production costs include harvesting, transportation, as well as milling costs. The criteria for determining when to stop a run was based on the average absolute percentage deviation of the end product from the target demand for each mill, their distribution around the demand, and the number of locations violating the access constraints. The model takes 6 minutes (about 120 iterations) to arrive at a solution if road access costs are zero, and about 20 minutes (about 400 iterations) if access costs are $20,000 per location. The maximum deviation of each end product from target demands for any period for the model to converge was set at 3%. Table 3 shows that all the model runs produced satisfactory results, with all average mill deviations less than 2%. The model also performed very well in

A Decomposition Approach to Integrated Forest Harvest Scheduling…

19

terms of the integer constraints, as there were no violations of this constraint when the model converged. Furthermore, the differences between objective and lagrangian function values, which measure model convergence, were 0.0005% and 0.0003% for the Baserun and Access Model respectively.

Effect of Access Costs on Marginal Costs The results show a systematic agreement with our theoretical expectations regarding the impacts of access on the harvest schedule. The results in table 3 reveal that in the Baserun, wood was harvested from all locations except 49 in at least one period throughout the planning horizon. On the other hand, when access costs are $20,000/location, 76 locations are unaccessed. Positive road building costs therefore tend to reduce the number of locations accessed and concentrate harvesting to only locations where it is economically profitable to do so. This is further shown in table 3 by the fact that a smaller area was harvested in the Access Model, than in the Baserun. Economic intuition suggests that the access costs in the Access Model might be considered a fixed cost over all the stands within a location. Hence, there will be incentives to harvest more per ha than when the access cost is treated as a marginal harvesting cost in terms of $/m3 as in the Baserun. Therefore more stands per location were harvested and fewer areas were accessed in a particular period in the Access Model than the Baserun. Table 3 also shows that the NPV of the Access Model is about $3.97 million less than the NPV of the Baserun. The small difference in the NPV may be because road access costs are incorporated as a smooth marginal cost in the harvesting costs for the Baserun. Table 3. Comparisons of the two models in terms of the deviations from mill demands, areas harvested, and the net present values, for the planning horizon

Model run

Baserun Access Cost Difference

Average absolute deviations (%) from Demand Constraint Sawmill OSB mill 1.395 1.323 0.590 0.864

Number of locations not accessed

Total Area harvested (ha)

Net present value (106 $)

49 76 27

310,909 293,156 17,753

596.70 592.73 3.97

The shadow prices on the mill demand constraints for lumber and OSB mills for both models are shown in figure 4. These shadow prices are the marginal costs of regenerating, harvesting, accessing, transporting the wood to the millgate, and milling for each mill. Shadow prices (marginal costs) for the sawmill are significantly higher in the Access Model than in the Baserun and both are increasing over the planning horizon. This is consistent with the lower NPV for the Access Model than the Baserun shown in table 3. We also observe that the difference between the marginal costs of the two models becomes greater in the later planning periods. The increasing marginal costs signal the scarcity of conifer wood in the permanently accessed locations, and suggest that more locations have to be accessed in order to meet the mill demands. The data presented in the first row of table 4 show that more areas are accessed later in the planning horizon. However, for the OSB mill, the marginal costs for

20

David M. Nanang and Grant K. Hauer

the Access Model are only slightly higher than the Baserun and both decrease slightly over time (figure 4).

Figure 4. Comparison of the shadow prices for lumber and OSB for the Baserun and Access Model.

The reason for the small difference in the marginal costs of the OSB mill between the two models may be that the demand specified for aspen is low, and so there is enough aspen on the land base to satisfy this demand at low marginal costs. The decreasing costs due to the abundance of aspen off-set the increasing marginal cost effect of including the access cost. It may also be the case that since both species types are harvested once a location is opened, the high value of conifer is subsidizing the road construction costs for aspen.

Impacts of Access Costs on Road Development and Harvest Schedule Analyses of the harvest schedule for each mill revealed how the transport destinations for wood in each location change under the two models in the first and second planning periods. Figures 5a and 5b show the distribution of the 192 permanently accessed locations, and wood flow from non-permanently accessed locations for the first and second periods in the planning horizon. The woodflow was in line with our expectations that wood from non-POLs will move to the nearest POLs in order to minimize the costs of road access.

A Decomposition Approach to Integrated Forest Harvest Scheduling…

Figure 5a. Permanent access and directions of woodflow for the Baserun in period 1.

Figure 5b. Permanent access and directions of woodflow for the Access Model in period 1.

21

22

David M. Nanang and Grant K. Hauer

Figure 6a. Permanent access and directions of woodflow for the Baserun in period 2.

Figure 6b. Permanent access and directions of woodflow for the Access Model in period 2.

A Decomposition Approach to Integrated Forest Harvest Scheduling…

23

It is also obvious that almost all the non-POLs accessed were concentrated around permanent access. The lack of explicit access cost in the Baserun resulted in more non-POLs accessed than in the Access Model, whilst the inclusion of access costs shifts the harvesting onto the permanently accessed land base and spreads harvesting to the south as well. The harvest schedules, shown in figures 7 – 10, reveal the differences in the supply locations that are harvested and how much is harvested in each supply location during the first two periods in the planning horizon. The schedules for both periods and models show that more locations with permanent access were harvested than those that had no permanent access. The Baserun consistently harvested more non-POLs than the Access Model, which implies that the cost of access provision was a disincentive to harvest wood from locations that are not permanently opened. Furthermore, the fact that access costs are fixed over multiple stands means there is an incentive to concentrate the cut rather than spread it out. It was also observed that all non-POLs opened under the Access Cost model in the first two periods were locations close to Drayton Valley, whilst the non-POLs opened in the Baserun were more spread out and farther away from Drayton Valley. Again, this is an expected result, as the road building costs will make stands far away from the demand center uneconomic to open. A comparison of the number of locations harvested in period 1 and period 2 shows that for both models and location types, the number of harvested locations were higher in period 2 than period 1, and many more locations farther away from the demand center were harvested. Finally, we can conclude from a comparison of the pattern of harvested locations between POLs and non-POLs in the Access Cost Model that it was cheaper to harvest and transport wood from POLs that were far away from Drayton Valley than to open up locations close to the demand center. These results therefore indicate that the nature of the distribution of harvests on the whole landscape is highly dependent on the initial layout of permanent access on the landscape.

Figure 7a. Wood procurement zone from Non-Permanently Opened Locations for the Baserun in Period 1.(Total number of locations harvested = 47).

24

David M. Nanang and Grant K. Hauer

Figure 7b. Wood procurement zone from Non-Permanently Opened Locations for the Access Cost Model in Period 1. (Total number of locations harvested = 9).

Figure 8a. Wood procurement zone from Permanently Opened Locations for the Baserun in Period 1. (Total number of locations harvested = 88).

A Decomposition Approach to Integrated Forest Harvest Scheduling…

25

Figure 8b. Wood procurement zone from Permanently Opened Locations for the Access Cost Model in Period 1. (Total number of locations harvested = 109).

Figure 9a. Wood procurement zone from Non-Permanently Opened Locations for the Baserun in Period 2. (Total number of locations harvested = 89).

26

David M. Nanang and Grant K. Hauer

Figure 9b. Wood procurement zone from Non-Permanently Opened Locations for the Access Cost Model in Period 2. (Total number of locations harvested = 14).

Figure 10a. Wood procurement zone from Permanently Opened Locations for the Baserun in Period 2. (Total number of locations harvested = 126).

A Decomposition Approach to Integrated Forest Harvest Scheduling…

27

Figure 10b. Wood procurement zone from Permanently Opened Locations for the Access Cost Model in Period 2. (Total number of locations harvested = 153).

Table 4 shows the number of locations opened in each period and changes in the average area harvested. The number of locations opened for the Access Model increased from 9 in the first period to a high of 74 in the ninth period. In the first few periods, there is enough wood in the permanently accessed areas to meet mill demands, and so fewer unaccessed locations are opened. But as these are harvested, and given the minimum 4 periods between harvests, more locations need to be accessed. This is the main reason for the divergence in the marginal cost at the mills over time. The average area harvested per location is higher for the Access Model in all periods than the Baserun. This is to be expected since large volumes have to be harvested to justify opening up the locations in the first place. This shows intensive harvesting in each location when access costs are positive as a result of the extra cost of accessing more stands. In fact, on average, approximately 52 ha more area are harvested per location in each period in the Access Model than the Baserun.

Table 4. Comparison of number of locations opened, areas harvested, and the shadow prices on the access constraint by period for the Baserun and Access Model Planning period 1 2 9 14 (49)* (90)

3 33 (128)

4 43 (147)

5 61 (222)

6 52 (238)

7 68 (242)

8 68 (262)

9 74 (295)

10 69 (222)

Area harvested (‗000 ha)

29 (28)

23 (23)

23 (23)

23 (24)

25 (24)

24 (26)

24 (25)

35 (36)

49 (57)

47 (59)

Average area harvested/ location (ha)

244 (208)

140 (108)

120 (83)

131 (81)

136 (67)

140 (72)

143 (71)

149 (91)

190 (124)

203 (148)

Cost/m3 of opened locations (Average t) Cost/m3 of closed locations (Average t)

0.50

0.38

0.41

0.59

0.69

0.57

0.52

0.96

1.02

1.28

4.94

4.87

5.16

5.75

6.58

8.49

9.64

11.81

11.62

12.13

No. of closed locations opened

*Note: Numbers in parenthesis are the Baserun Model equivalents.

A Decomposition Approach to Integrated Forest Harvest Scheduling…

29

Shadow Prices on the Access Constraint The shadow prices associated with the access constraint [Equation 5] for each period are given in the last two rows of table 5. The shadow price,

jt

, can be interpreted as either costs

or benefits of opening up a location. It represents the value of being able to relax constraint (Equation 5) by one unit – in other words, be able to harvest one more m3 of wood without actually having to access the location. In this sense

jt

represents a net value of wood (net of

transport and harvest costs) per cubic meter coming from a particular location. This is the interpretation implied by Equation 16, where

represents the amount that wood would

jt

have to be worth to justify opening an area. The other way of interpreting it is that the jt

represents the marginal cost of having to access the area in order to harvest another m3 of

wood. This interpretation of

jt

is consistent with Equation 19, where

jt

is the marginal

3

cost of accessing a location for purposes of harvesting a m of wood. From Equation 19, it implies that the presence of

jt

makes the marginal cost of harvesting a small amount of

wood in a closed location, which a timber harvest-scheduling model without the fixed access cost would schedule for harvest, very high. This marginal cost is subtracted from the marginal value of wood, which eventually squeezes the volume flow from the locations with small wood flows to zero. The shadow prices on the access constraint (

jt

) increase over time (table 4). This result

implies that the marginal value of the wood is increasing over time, which would be consistent with lower wood flows across each location in the future. Lower wood flows require higher marginal wood values in order to justify the higher cost/m3 road building cost that occurs. The shadow prices of the opened locations are significantly lower than those of closed locations because the marginal access cost of increasing the wood flow in opened locations is in fact zero. The large differences in the shadow prices between the opened and closed areas show that most of the closed areas have small volumes of harvestable wood and so they are not profitable to open if access costs are included. Therefore, given the assumptions of the model, the prices of wood products in the closed locations have to increase by the average amounts given in the last row of table 4 to make these locations economic to open. The distribution of locations according to the number of periods they were opened throughout the planning horizon is given in table 5. The table provides information on the number of non-POLs that were opened 0, 1, …,10 times during the planning horizon. It shows that for the Access Model, no location was opened more than 5 times, whilst for the Baserun, the maximum number of times locations were opened was 10.

Table 5. The distribution of locations according to the number of times opened during the planning horizon Number of times opened Model Type Baserun Access Model

0 49

1 14

2 26

3 28

4 30

5 55

6 51

7 55

8 44

9 24

10 9

76

163

117

24

3

2

0

0

0

0

0

*Note: These frequencies do not include the 192 permanently opened locations.

A Decomposition Approach to Integrated Forest Harvest Scheduling…

31

The inclusion of access costs considerably reduces the frequency with which a given location is opened. This result could be useful if provision of access is important for nontimber values in the forest, especially if recent evidence of harvesting activities in the FMA negatively impact on recreation or other non-timber benefits.

DISCUSSION The approach presented in this paper holds great promise for use in practice to examine the impacts of road construction costs on long-term timber supply. The case study shows that the model we developed is capable of addressing the problem of jointly solving the forest management and access development problem. Solving large mixed integer linear programming problems that include silvicultural and access considerations is very difficult for a large number of integer variables, and has been investigated for a long time. The method used here provides a least cost strategic access plan for constructing roads with large temporal and spatial detail. Furthermore, with integer variables in the access cost model, the model took only about 20 minutes to converge to a solution. The results of this paper are consistent with economic theory and intuition regarding the effects of incorporating access costs in timber management scheduling. One of the effects of access costs on scheduling is on the timber values. Timber values with and without access costs were estimated using the NPV of the Access Model and Baserun respectively. A comparison of the NPVs between the Baserun and Access Model show that the difference was small. The reasons for the small difference could be because road access costs are incorporated as a marginal cost in the harvesting costs for the Baserun. The economic implication of the closeness of the NPVs however, is that given the assumptions in our model, future access development in the FMA will not reduce timber revenues significantly. Another important application of this approach lies in its ability to estimate the shadow prices of all constraints in the model. The shadow prices on the demand constraints indicate the marginal costs of producing the final products. Marginal costs for the sawmill were higher than the OSB mill and increased over time when access costs were $20,000/location, compared to the scenario with zero access costs. Therefore when access costs are high, marginal costs increase accordingly, and so fewer locations are harvested. For the OSB mill, marginal costs under the Baserun and Access Model remained relatively constant and decreased slightly over the planning period. This may suggest that the maximum demand level set for the OSB mill is low compared to what the forest can sustain. Therefore, the harvest of aspen may need to increase in future. Secondly, the shadow prices on the access constraint give us the average costs of road construction per cubic meter of wood harvested, if the location is open. This information is a useful indicator of how expensive it is to invest in road development, and whether it is profitable to do so. The shadow price for closed locations indicates the minimum dollar value that should be paid for cubic meter of wood to make it profitable to open the location. This information is important in determining whether road construction to unaccessed locations make economic sense. Hence, the model provides a way of relating the wood production to marginal costs and values of timber, which can be compared to expectations of future timber prices. This provides valuable information for supply planning and current planning in silvicultural and road investment expenditures. For

32

David M. Nanang and Grant K. Hauer

example, by conducting sensitivity analyses, it is possible to determine how much wood can be profitably harvested given a fixed road budget, or given a fixed demand, how much it will cost to build roads to satisfy that demand. The schedules for the two models for the first two periods in the planning horizon also revealed very important implications of considering access costs in long-term timber supply analyses. The harvesting pattern was contrary to a common sense expectation that locations that have permanent access will necessarily be harvested before opening up any unaccessed areas. In the Baserun, locations without permanent access and close to the demand center (Drayton Valley) were accessed and harvested before POLs that were far away from the demand center. In contrast, POLs that were far away from the demand center were harvested before opening up locations that were close to Drayton Valley in the Access Model. As the marginal values of final timber products rise in later periods of the planning horizon, the value of wood in the closed locations increase accordingly, and so makes it profitable to open up adjacent closed areas. An important conclusion is that the inclusion of access costs determines both the initially harvestable stands and subsequent road development. Access development during the planning horizon is also dependent on the layout of the permanent access within the forest, as road construction spreads from these POLs to adjacent closed locations. The inclusion of positive access costs has the tendency to concentrate forest management activities to fewer locations, and increase the area harvested per accessed location. This is easily verified from a comparison of the areas harvested/location, as well as the number of locations accessed under either model given in table 4. If forest management involves nontimber benefits (e.g., recreation or hunting), then the number of locations accessed becomes an important consideration. For example, access to areas has most often shown to negatively affect hunter utility of hunters (e.g., McLeod et al., 1993). In this case, fewer access areas due to positive access costs will tend to increase the non-timber benefits. Of course, there may be situations under which provision of access increases non-timber values. It is therefore important that long-term analysis of timber supply incorporate access costs as this impact on not only the timber values, but the non-timber values as well. Although this model investigated a specific example of a forest access problem, it is possible to evaluate other management problems related to access and to make the solution method more efficient. For example, the present set up of the model allows a location to be opened for one period (10 years), after which it is either closed or opened again in the next period. However, if a two- or three-pass harvest system is used, it may require that areas that are opened in one period remain opened for the next two or three periods. Our model further assumes that the POLs are opened and maintained at no cost. It is highly probable that the construction and maintenance costs associated with permanently opened all-weather roads will make most stands unprofitable to harvest. Also, we have not explicitly dealt with the decommissioning (closing) of roads at the end of each planning period. The cost of closing roads is currently lumped into the road construction costs. Multiple pass harvesting will require that these costs be separated, as they will occur in different time periods. Another issue that can be investigated is possible inefficiency in the cost minimizing routes that result from the model set-up and solution technique employed. The model is currently set up such that all wood from unaccessed locations has to pass through the permanently accessed locations. In a case of multiple mill destinations, it is possible for that route to be longer (and more expensive) than constructing a road directly from an unaccessed location to a mill.

A Decomposition Approach to Integrated Forest Harvest Scheduling…

33

Finally, although the model described in this paper dealt only with timber supply, the inclusion of access provides the necessary framework to extend the model to consider nontimber values, especially recreational hunting.

CONCLUSIONS This study applied an optimization approach to demonstrate how an extension of the dual decomposition technique of Hoganson and Rose (1984) could be used to integrate forest scheduling and access activities. The application of this model in this paper shows the method is effective for generating optimal near feasible solutions within a short computer runtime of about 20 min. The model was applied to a large temporal and spatial forest managementscheduling problem on a Forest Management Agreement area near Drayton Valley, Alberta. The results reveal that inclusion of access costs concentrates forest management activities to fewer locations over the planning period compared to when it costs nothing to open up the areas. Also, positive access costs reduce the frequency with which locations are accessed during the planning horizon. The model provides important shadow price information that is useful for determining how access cost affects each demand location in the model. Using this framework, the model can be extended to deal with multiple-pass harvesting, decommissioning of roads, and non-timber benefits. The algorithm could also be extended to include variable access costs depending on factors such as terrain, availability of road materials, etc.

REFERENCES Adamowicz, W. L., Sawit, J., Boxall, P. C., Louviere, J., and Williams, M. (1997). Perceptions versus objective measures of environmental quality in combined revealed and stated preference models of environmental valuation. Journal of Environmental Economics and Management. 32(1): 65-84. Andersson, D. (2005). Approaches to integrated strategic/tactical forest planning. Report 16. Department of Forest Resource Management and Geomatics. Swedish University of Agricultural Sciences, Umeå, Sweden. 29p. Anderson, A. (2005). Planning methods to reduce costs and enhance value recovery in sustainably managed forests. Technical Report #3. Strategic Road Network Projection. Canadian Forest Products Ltd. Fort Nelson Division. 10p. Aulerich, S. (1999). Strategic Harvest and Transportation Planning- The Foundation of Forest Activities. Paper presented at the FEG International Forestry Engineering Conference; June 28-30, 1999; Edinburgh, Scotland. Bare, B. (1972). Applications of operations research in forest management: a survey. Paper No. 28, Center of Quantitative Science on Forestry, Fisheries and Wildlife. University of Washington, Seattle. Barnes, B., and Sullivan, E. C. (1980). Timber transport model, Version 2.0. University of California, Berkeley, Institute of Transportation Studies, Research Report. UCB-ITS-7918. 126p.

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Bullard, H. S., Sherall, H. D., and Klemperer, W. D. (1985). Estimating optimal thinning and rotation for mixed-species timber stands using a random search algorithm. Forest Science. 31: 303-315. Clark, M. M., Meller, R. D., and McDonald, T. P. (2000). A three-stage heuristic for harvest scheduling with access road network development. Forest Science. 46(2): 204-218. Clements, S. E., Dallain, P. L. and Jamnick, M. S. (1990). An operational spatially constrained harvest scheduling model. Canadian Journal of Forest Research. 20: 14381447. Dahlin, B., and Sallnas, O. (1993). Harvest scheduling under adjacency constraints-a case study from the Swedish sub-alpine region. Scandinavian Journal of Forest Research. 8:281-290. Epstein, R., Weintraub, A., Sapunar, P., Nieto, E., Sessions, J. B., Sessions, J., Bustamante, F., and Musante, H. 2006. A combinatorial heuristic approach for solving real-size machinery location and road design problems in forestry planning. Operations Research. 54 (6): 1017-1027. Fisher, M. L. (1981). The lagrangian relaxation method for solving integer programming problems. Management Science 27(1) 1-18. Fisher, M. L. (1985). An applications oriented guide to lagrangian relaxation. Interfaces. 15: 10-21. Geoffrion, A. M. 1974. Lagrangian relaxation and its uses in integer programming. Mathematical Programming Study. 2. 82-114. Hauer, G. K. (1993). Timber management scheduling with multiple markets and multiple products. Unpublished M. S. Thesis. University of Minnesota. 122p. Hoganson, H. M., and Rose, D. W. (1984). A simulation approach to optimal timber management scheduling. Forest Science. 30(1): 220-238. Johnson, K. L., and Scheurman, H. L. (1977). Techniques for prescribing optimal timber harvest and investment under different objectives-Discussion and Synthesis. Forest Science Monograph. 18. 31p. Kirby M. (1973). An example of optimal planning for forest roads and projects, in: Planning and decision making as applied to forest harvesting, In J. E. O'Leary (Ed.). Proceedings of a Symposium held September. 11-12, 1972 (pp 75-83). Forest Research Laboratory, School of Forestry, Oregon State University, Corvallis. Kirby, M., Wong, P., and Wallace, C. (1979). Optimization of Rural road networks- an application of the timber transshipment model. In: Roads of Rural America. U. S. Dept. of Agriculture, Economics, Statistics and Co-operatives Service. ESCS-74. Pp 17-26. Kirby, M. W., Hager, W. A. and Wong, P. (1986). Simultaneous planning of wildland management and transportation alternatives. In Systems analysis in forestry and forest industries (pp 371-387). Studies in the Management Sciences. Vol. 21. Kirkpatrick, S., Gelatt, C. D., and Vecchi, M. P. (1983). Optimizing by simulated annealing. Science. 220:671-680. Lockwood, C., and Moore, T. (1993). Harvest scheduling with spatial constraints: A simulated annealing approach. Canadian Journal of Forest Research. 23: 468-478. McLeod, K., Boxall, P. C., Adamowicz, W. L., Williams, M., and Louviere, J. J. (1993). The incorporation of nontimber goods and services in integrated resource management. I. An introduction to the Alberta moose hunting study. Interim Report. Staff Paper, Department of Rural Economy, Univ. of Alberta. Staff Paper 93-12.

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Murray, A. T., and Church, R. (1995). Heuristics solution approaches to operational forest planning problems. OR Spektrum. 17:193-203. Nanang, D. M., and Hauer, G. K. (2008). Integrating a random utility model for nontimber forest users into a strategic forest planning model. Journal of Forest Economics. 14(2): 133 -153. Nelson, J., and Brodie, J. D. (1990). Comparison of a random search algorithm and mixed integer programming for solving area-based forest plans. Canadian Journal of Forest Research. 21: 595-600. Nelson, J. D., and Finn, S. T. (1991). The influence of cut block size and adjacency rules on harvest levels and road networks. Canadian Journal of Forest Research. 20: 934-942. O‘Hara, A. J., Faaland, B. H., and Bare, B. B. (1989). Spatially constrained timber harvest scheduling. Canadian Journal of Forest Research. 19: 715-724. Sullivan, A. (1973). A transportation analysis technique for national resource management. International Conference on Transportation research, Bruges, Belgium, June, 1973. Walters, K. R. (1991). Spatial and temporal allocation of strata-based harvest schedules. M.Sc. thesis, Univ. of New Brunswick, Fredericton. Weintraub, A., and Navon, D. (1976). A forest management model integrating silviculture and transportation activities. Management Science. 22 (12): 1299-1309.

APPENDIX: SOLUTION ALGORITHM The model was solved using a variant of the dual decomposition algorithm proposed by Hoganson and Rose (1984). The solution algorithm for this problem described below is based on the first order conditions of the lagrangian function derived above (Equation 12). The algorithm begins by solving each stand level problem using initial guesses at the shadow prices for each forest wide constraint for both POLs and initially closed locations. The following steps are used to solve the model: Algorithm Step 1: Guess at the initial shadow prices (πjt‘s and

jt‘s).

Algorithm Step 2: Calculate Wood Prices In Each Permanently Accessed Location (The Θjt‘s) Using Equation 18 For all POLs, we determined the price of wood in each permanently accessed location using Equation (18), which implies that the value of wood at location j is equal to the mill price minus transportation costs. That is, jt

jt

it

c sjit . The maximum of these

determines which mill should receive wood from which POL.

Algorithm Step 3. Solve for the Wood Prices at Each Unaccessed Location (the Ujt‘s) Using Equation 23 To determine the value of wood in the unaccessed locations, we defined sub-destinations on the way to the mills at locations that are permanently accessed and adjacent to areas that

David M. Nanang and Grant K. Hauer

36

are not accessed. Also, each unaccessed location is a subdestination. This means that the subdestinations accumulate volumes not only from harvest within their associated supply locations but also from other locations that ship wood through those subdestinations. To determine the direction in which wood should be shipped between locations, we use the first order condition given by Equation (17). Equation (17) implies that the net value of wood at location k is equal to the maximum value over all shipping alternatives from k (that is the value at each adjacent j minus the shipping cost to j). This implies the wood should be moved to the location that gives the highest net value. The price of wood in each subdestination was calculated by solving iteratively the dynamic programming formulation given by Equation (23) (which is a combination of Equations (19) and (17):

u jt

max u kt k I Bj

c sjkt

jt

( z jt 1)

(23)

Algorithm Step 4. Solve the Stand Level Scheduling Problems (Equations 14, 15, 21 and 22) Using Dynamic Programming Once the prices of wood in the POLs and the initially closed locations (the

jt

' s and

u jt ' s ), are estimated, we use these estimates to solve the stand level management problem given by Equations (14), (15), (21) and (22). These stand level decisions include harvest timing for initial and subsequent harvests, mill destination for each timber type, and regeneration options. On the dual side these stand level variables are the a sj ' s and

s sj ' s whilst on the primal side it refers to the xsjt ' s . Algorithm Step 5. Add up the Wood Flows in Each Location and to Each Mill s jt

(y ,

p y sjkt , And y jit , )

Algorithm step 6. Determine the access schedule (the zjt‘s) using equation 16. At an optimal solution

jt

from Equation (16) must satisfy

hand side of this equation represents a lower bound on less than c Ajt / y sjt variable

jt

jt

jt

c Ajt / y sjt

. The right

if an area is opened. If

jt

is

, then the location cannot be opened. The interpretation of the dual

, given Equation (16), represents the net value of wood per cubic meter (net of

transport and harvest costs). If the net value per cubic meter is greater than the access cost per cubic meter then it makes sense to ship wood over the location. Algorithm Step 7. Check if solution is near feasible. If solution is near feasible then stop otherwise go to step 8.

A Decomposition Approach to Integrated Forest Harvest Scheduling…

37

The solution is checked for near feasibility by summing up the volume flows p jit

( y ' s ) implied by the harvest timing and transportation decisions and compared to the mill demand constraint levels. If the volume flows deviate from the demand constraints by greater than 3%, the shadow prices on the demand constraints are adjusted as described below. Algorithm Step 8. Re-estimate shadow price for access constraints (the

jt

‘s)

The shadow prices on the access constraints are adjusted based on Equation (6), which is given as: y sjt

y sjt z jt . This equation basically states that wood cannot be harvested from or

transported through an unaccessed location. Therefore, after solving the stand level problems, the algorithm checks all locations and calculates a deviation for the constraint as

y sjt

dev jt

y sjt z jt . The deviation is either positive or zero. A positive deviation means

that wood is harvested from or transported through a location that is not accessed ( z jt

0 ).

In this case, the shadow price on the constraint is adjusted upward for that location in the next

y sjt

iteration. That is, for dev jt

y sjt z jt

0,

1 jt

0 jt

, f g (dev jt ) , where

jt

is the

shadow price on the access constraint. The function fg is piecewise linear which gives price adjustments as a function of the deviation ( dev jt ). The function gives small price changes for small deviations and large price changes for large deviations.

y sjt

If the dev jt 1 jt

0 jt

opened its between the

f0

c Ajt y

s jt

y sjt z jt 0 jt

0, y sjt

s

must be greater than c jt / y jt jt

1, then the price changes are based on

. The deviation is always negative since for a location to be A

jt

0, z jt

. The price changes are large if the difference

in a particular iteration and the previous iteration,

c Ajt

0 jt

y sjt

, is large, and

vice versa. Algorithm step 9. Re-estimate the mill demand shadow prices (the

it

‘s) and go to Step

2. If the wood flows deviate from mill demand levels then the shadow prices are adjusted using simple intuitive shadow price adjustment procedures described by Hoganson and Rose (1984) and modified by Hauer (1993).

In: Forest Management Editor: Steven P. Grossberg

ISBN: 978-1-60692-504-1 © 2009 Nova Science Publishers, Inc.

Chapter 2

REDUCED-IMPACT LOGGING AND POST-HARVEST MANAGEMENT IN THE ATLANTIC FOREST OF ARGENTINA: ALTERNATIVE APPROACHES TO ENHANCE REGENERATION AND GROWTH OF CANOPY TREES Paula I. Campanello 1,2,3, Lía Montti 1,2, Patricio Mac Donagh and Guillermo Goldstein 1,2,4

3

1

Laboratorio de Ecología Funcional, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II 2º piso, C1428EHA, Buenos Aires, Argentina 2 Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina 3 Facultad de Ciencias Forestales, Universidad Nacional de Misiones, Bertoni 124, Eldorado, Misiones, Argentina 4 Department of Biology, University of Miami, P.O. Box 249118, Coral Gables, Florida 33124, USA

ABSTRACT Selective logging is the most common method of timber extraction in native tropical and subtropical forests, including the Atlantic Forest of South America. Uncontrolled conventional logging has resulted in impoverished forests that have lost much of their economical value and biodiversity. In poorly logged forests in sub-tropical Argentina, bamboos colonize felling gaps and inhibit canopy tree regeneration while lianas slow the growth rate of most canopy trees. Reduced impact logging techniques along with postharvest silvicultural treatments to enhance canopy tree growth and regeneration have been shown to be effective in the Atlantic Forest eco-region, but destructive timber mining practices nevertheless continue.

40

Paula I. Campanello, Lía Montti, Patricio Mac Donagh et al.

INTRODUCTION Unplanned selective logging by untrained and poorly supervised crews is still the most common method used for timber extraction in tropical and subtropical forests. Natural gap dynamics are profoundly altered by this timber extraction method because the removal of a few trees per unit area causes substantial and avoidable damage to the vegetation adjacent to the harvested trees, including trees that could be used in successive harvests (i.e., future crop trees). Most research on methods for enhancing tree growth with selective harvesting of tropical forests have focused on (i) reduced-impact logging designed to mitigate the deleterious ecological impacts of tree felling, yarding and hauling, and (ii) post-harvest silvicultural treatments, mainly liana cutting and girdling competitors with future crop trees (Putz et al., 2008). In the Atlantic forest of northern Argentina reduced-impact logging has been scarcely implemented and post-harvesting silvicultural methods barely applied. Moreover, trees to be felled are selected by the chain saw operator and usually sought with the skidder, resulting in unnecessary damage of the nearby trees. These unplanned operations have profound impacts on the structure, functions and dynamic of this forest ecosystem. Selective logging typically creates gaps that are 5 to 6-fold larger than those found in undisturbed forests (Pereira et al., 2002). Incoming solar radiation, soil and air temperature, evaporative demand and soil water availability also change in gaps and logging roads (Whitmore et al., 1993; Van Dam, 2001; Campanello et al., 2007a). Selective logging also results in soil compaction which modifies soil structure, seed germination, water and nutrient cycling, and changes plant species composition and faunal diversity and dynamics (Guariguata and Dupuy, 1997; Olander et al., 2004). After uncontrolled logging, Atlantic Forest typically develops heavy infestations of lianas and bamboos that colonize disturbed sites, inhibit the growth of tree seedlings and saplings, and become the dominant understory species (Tabarelli and Mantovani, 2000; Campanello et al., 2007a). Alternative selective harvesting and post-harvesting methods that reduce the impact of invasive species and enhance canopy tree growth and regeneration will be discussed for the Atlantic Forest eco-region. Most of the examples and the conceptual framework are based on our experience in the southern portion of the Atlantic forest ecoregion in north-eastern Argentina (Figure 1). This subtropical endangered ecosystem represents the southern limit of distribution for many tropical plant species and genera. Due to infrequent low temperatures occurring during the winter many canopy species are deciduous. As a result, an increment in the solar radiation reaching the understory occurs in the less favorable season, which may favor perennial non-timber species (e.g., some native fastgrowing bamboos) that are resistant to freezing temperatures. Development of sustainable management techniques needs a sound knowledge of ecosystem functioning including understanding of the effect of invasive bamboo species and lianas in the dynamics and structure of the forest. Acquisition of information on tree seed production and dispersal, as well as on seedling establishment, is also necessary to help refine management prescriptions.

Reduced-Impact Logging and Post-Harvest Management…

41

THE ATLANTIC FOREST ECO-REGION The Atlantic Forest eco-region, with an extent of 1.36 million km2, is distributed along 3300 km of the Atlantic coast of Brazil, southeastern Paraguay, and northeastern Argentina (Figure 1). Just a few centuries ago it was the second most extensive forest ecosystem in the Neotropics after the Amazonian forest. Unlike Amazonian forest, more than 93% of the original cover of the Atlantic Forest has been lost due to human colonization and timber exploitation starting in the XVI century in Northeastern Brazil, and reaching extraordinarily deforestation rates during the last century because of accelerating rates of timber exploitation and agricultural expansion (Gusmão Câmara, 2003; Tabarelli et al., 2005). The Atlantic Forest is the most devastated and most highly threatened tropical ecosystem on the planet (Galindo-Leal and Gusmão Câmara, 2003). Despite the fact that most of this forest ecosystem has been lost (Figure 1), the remnants still have high biological diversity and endemism and are included among the 25 top biodiversity hotspots in the world (Myers et al., 2000). Unfortunately, no more than 2% of the original area is legally protected in natural reserves and parks (Tabarelli et al., 2005).

Figure 1. Original range and current remnant forest stands of the Atlantic forest eco-region in Brazil, Paraguay and Argentina. The Atlantic forest distribution in Misiones Province (Argentina) is indicated on the right side of the figure concurrently with the intensive study sites where information was obtained and used in the text, tables and figures. INR is Iguazú National Reserve. INP is Iguazú National Park. San Jorge, La Elina 1 and 2 and Guaraní are private properties. Guaraní is a reserve owned by the University of Misiones located inside the Yabotí MAB Reserve (RBY).

The Atlantic Forest region is extremely heterogeneous in structure and species composition as a result of different climatic and edaphic conditions across its distributional range, which spans from near the equator to 32o south, and along altitudinal gradients ranging from sea level to 2900 m asl. The seasonality of these forests is variable and total annual

42

Paula I. Campanello, Lía Montti, Patricio Mac Donagh et al.

precipitation ranges from 4000 to 1000 mm. Temperature regimes also change when moving from tropical to subtropical climates, from the northern to the southern limit of the Atlantic Forest distribution. Accordingly, two major different forest ecosystem types have been recognized: the Atlantic Rain Forest mainly along the Brazilian coast, and the inland Semideciduous Atlantic Forest (Oliveira Filho and Fontes, 2000). The semi-deciduous Atlantic forest includes forests in northern Argentina, southern Brazil, and southeastern Paraguay with an original extent of 500,000 km2. In Brazil and Paraguay, only fragments of these forests remain, comprising less than 8% of the original forest (Galindo-Leal and Gusmão Câmara, 2003). In contrast, nearly 11,000 km2 of semideciduous Atlantic forest remains in Argentina in Misiones Province (44% of the original cover in this country), which represents the largest remnant of continuous semi-deciduous Atlantic Forest (Figure 1). Conservation of these large forest areas was possible because the colonization process in Misiones occurred only late in the XIX century (Chebez and Hilgert, 2003). Settlement was heading primarily to consolidate the country borders, and was based on the exploitation of forest resources. At the same time, extensive deforestation for agriculture and cattle was occurring in Brazil (Holz and Placci, 2003). The rate of deforestation in the province of Misiones, however, has accelerated markedly in recent years due to increasing population size in the region and increasing demand for wood products coupled with a reduced economic value of the remaining forests as a result of uncontrolled selective logging. Mean annual precipitation in the Argentinean semi-deciduous Atlantic Forest is about 2000 mm and is evenly distributed throughout the year. Mean annual air temperature is 21 ºC with monthly means of 25 ºC in January and 15 ºC in July, the warmest and coldest months of the year, respectively. Even though, temperatures drop considerable during the winter season, it seldom freezes; the number of days per year with temperatures below 0 ºC ranges from 0 to 12 depending on the year. This subtropical forest has three canopy strata with numerous epiphytes and lianas. Trees of the Lauraceae and Fabaceae dominate the canopy. Some common dominant canopy trees are Nectandra megapotamica (Spreng.) Mez (Lauraceae), Ocotea puberula (Rich.) Ness (Lauracea), Myrocarpus frondosus Fr. All. (Fabaceae), Lonchocarpus leucanthus Burkart (Fabaceae), Enterolobium contortisiliquum (Vell.) Morong. (Fabaceae), Parapiptadenia rigida (Benth.) Brenan (Fabaceae), Balfourodendron riedelianum (Engl.) Engl. (Rutaceae), Bastardiopsis densiflora (Hook. & Arn.) Hassler (Malvaceae), Cedrela fissilis Vell. (Meliaceae), Cordia trichotoma (Vell.) Arrab Ex Stend and Cordia americana L. (Boraginaceae). Emerging tree species such as Aspidosperma polyneuron Muell. Arg. (Apocynaceae) were heavily exploited in the past (Biloni, 1990). Common sub-canopy tree species are Sorocea bonplandii (Bailon) Burg., Actinostemon concolor (Spreng.) Muell. Arg., Trichilia catigua Adr. Juss. and Trichilia elegans A. Juss. Many of the upper canopy species are deciduous losing their leaves during the winter such as P. rigida , C. fissilis, E. contortisiliquum, and C. trichotoma. The semi-deciduous Atlantic Forest has a relatively high liana diversity and abundance (Hora & Soares, 2002; Morellato & Leitão Filho, 1996), and is very rich in native bamboos, some of which colonize disturbed sites and become the dominant understory species (Judziewicz et al., 1999). Bamboos of the genus Chusquea Kunth and Merostachys Sprengel may form impenetrable thickets in large gaps and other open canopy areas (Tabarelli and Mantovani, 1999), whereas lianas often infest more than 80% of the canopy trees (Campanello et al., 2007b). Despite Argentina holding the major continuous remnants of semi-deciduous Atlantic Forest, most of these forest stands were historically subjected to selective logging (Giraudo et

Reduced-Impact Logging and Post-Harvest Management…

43

al., 2003). These utilized forests are impoverished in timber species and have been invaded by native bamboos and lianas, which may contribute to increase the conversion pressure on these forests (Placci, 2000). During the last three decades, the area dedicated to pine plantations increased from 80.000 to 370.000 hectares as a result of the expansion of pulp mill industries, while activities such as cattle grazing and agriculture have increased only slightly (Izquierdo et al., 2008). Between the years 1998 and 2000, 67,200 ha of native forests in Misiones were converted to other uses (UMSEF, 2005).

EFFECTS OF CONVENTIONAL SELECTIVE LOGGING ON THE STRUCTURE AND FUNCTION OF THE ATLANTIC FOREST OF MISIONES Selective timber extraction is a common practice in tropical and subtropical native forests throughout South America. A recent study estimated that 12,100 to 19,800 km2 of the Brazilian Amazon are being logged every year (Asner et al., 2005). This method involves the removal of few large-sized individuals of commercial value in cutting cycles of 20–50 years. Most harvesting operations in tropical forests around the world conform to conventional logging (CL), meaning that logging is carried out generally by untrained and unsupervised workers. Depending on the forest type and the number of previous harvests, the harvested trees range from 4 to 10 logged trees per ha representing 1.6 to 5% of all the trees larger than 10 cm DAP (Table 1). Even at low harvesting intensities (i.e., 22% of the plants consumed (N = 65 species) and that both primates devote >40% of their foraging time throughout the year to the consumption of lianas (I. Agostini, unpublished data). Thus, liana cutting may be recommended with caution as a sustainable forest management technique. Contrary to the large number of studies documenting the effects of silviculture treatments on tree growth, relatively few studies have focused on treatments to enhance tree regeneration in tropical and subtropical forests. Limited regeneration of commercial light demanding species has been observed in tropical forests and in the subtropical forests of Misiones (Dickinson and Whigham, 1999; Mostacedo and Fredericksen, 1999; Fredericksen and Mostacedo, 2000; Campanello et al., 2007a). Potential reasons for impeded regeneration include the absence of seed trees, the lack of appropriate environmental conditions for seed germination and seedling establishment, and the proliferation of invasive plants that compete with tree sapling and seedling for light and nutrients (Mostacedo and Fredericksen, 1999). Weeds may also function as seed-traps preventing tree propagules from reaching the forest floor (Rother, 2006). The absence of regeneration of commercial tree species may also trigger forest conversion to other land uses, therefore focusing on invasive species control to ensure tree regeneration after logging should be a major concern for sustainable management in the tropics (Fredericksen and Putz, 2003). Bamboos and lianas best illustrate this assertion insofar as they are ubiquitous competitors in gaps, preclude tree regeneration and slow down gap-phase regeneration processes in tropical forests (Oliveira-Filho et al., 1994; Schnitzer et al., 2000; Tabanez and Viana, 2000; Tabarelli and Mantovani, 2000; Silveira, 2001; Griscom and Ashton, 2003; Schnitzer et al., 2005; Campanello et al., 2007a). In northern Argentina, the bamboo Chusquea ramosissima is very abundant in logged forests and forms a dense understory 2- to 3-m high that significantly reduces transmitted

Reduced-Impact Logging and Post-Harvest Management…

51

solar radiation. Consequently, the forest floor of bamboo-dominated gaps may experience solar radiation conditions similar to the forest floor under a dense tree canopy (Figure 6). Bamboo and liana cutting has substantial effects on forest microclimate, increasing solar radiation, soil water, and nutrient availability. As a result, enhanced growth was observed in cutting plots for saplings of several canopy species (Figure 7). Bamboo and liana cutting, however, seemed to improve only slightly the germination and recruitment of lightdemanding canopy tree species despite large increases in solar radiation and nutrients availability (Campanello, 2004). Apparently the biomass left to decompose in situ, after cutting, impeded seed germination or seedling establishment and increased sapling mortality. The leaves and stems of the bamboo C. ramosissima have low decomposition rates (i.e., between 3.5 to 4.5 years for 95% of the biomass to decompose; L. Montti, unpublished results). Also, gaps can be invaded by shrubs and herbs after bamboo and liana cutting (Campanello et al., 2007a). Plants from these functional groups may also stall succession in gaps (Chapman and Chapman, 1997; Paul et al., 2004). This information highlights the difficulties and importance of managing understory species in tropical and subtropical forests.

Figure 6. Hemispherical photos taken in a control (a, c) and a bamboo and liana cutting plots (b, d) at 0.7 m (a, b) and 2 m (c, d) above ground which illustrate the effect of the invasion of bamboos in small gaps on light distribution patterns near the forest floor. Fractions of solar radiation transmitted (FRT) are 1.5% (a), 17% (b), 20% (c), and 19% (d). Photos were taken at La Elina 2 research site in December 2001.

Paula I. Campanello, Lía Montti, Patricio Mac Donagh et al.

Relative growth rate

52

1.50

Control Bamboo and liana cutting

1.25 1.00 0.75

*

*

*

0.50 0.25 Balfourodendron riedelianum

Bastardiopsis densiflora

Lonchocarpus leucanthus

Nectandra megapotamica

Figure 7. Relative growth rates (RGR) in height of saplings of 30cm to 80 cm height for four dominant canopy tree species in plots subjected to bamboo and liana cutting and in control plots at La Elina research site. RGR was calculated as the difference in height during a period of one year divided by the initial height. Values are means + SE. * Indicates significant differences at p 45 cm, after 17 years of continuous monitoring in an equatorial ―terra firme‖ forest. Ferreira (1997) reported values from 3,9 to 3,7 m3.ha-1.a-1 in an experimental area located in secondary humid forest in Minas Gerais after 10 years. Thus it is clear that caatinga forest, in spite of the long and harsh dry season, can grow fast. Growth rates do not appear to be much affected by the difference in average rainfall between sites (935 mm year-1 in Formosa Farm, against 1360 mm year-1 in Maturi Farm). The frequency of dry years was higher in Formosa, where total rainfall was below 650 mm in three out of fourteen years (Figure 8), but again this is not reflected as a difference in increment rates between sites. The effects of coupe age on the distribution of stem volume per diameter classes can be seen in Figure 9. In the Legal Reserve area of Formosa Farm, 90% of the volume corresponds to stems from 4 cm to 20 cm DBH. In the coupes harvested at years 2000, 1999, 1998, 1997 and 1992, a slow transition to higher classes is evident, but even in F-1992, the oldest coupe, practically all volume corresponds to stems below 11 cm DBH. In the Legal Reserve of Maturi Farm volume is concentrated in stems between 4 and 22 cm DBH. In the harvested areas, more than 90% of standing stock corresponds to stems below 12 cm DBH. In this site, the distribution curves are somewhat broader, suggesting a faster stem class transition. In any case, it is quite clear that short cycles can not reproduce the original stem structure. Diameter increment is very slow after ten years, and any stem will probably require 40 years or more to achieve 20 cm DBH. Basal Area and Volume recovery rates were quite fast in both sites, reaching 80-120% of the initial value at year 14.

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Frans Pareyn, Enrique Riegelhaupt and Maria Auxiliadora Gariglio

Figure 8. Rainfall in Formosa and Maturi Farms, (averages 935 and 1360 mm yr-1).

Figure 9. Volume distribution per stem diameter classes.

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191

However, the distribution of stem volume by diameter classes suggests that much longer cycles will be needed to recover the original structure of the vegetation.

6. VEGETATION RICHNESS AND ABUNDANCE To assess the impacts of management on vegetation, two strata were separately analyzed: a) woody stratum (comprised of trees, shrubs, woody climbers), and b) herbaceous stratum (composed by grasses and herbs). Field data were collected between May and August, 2006. In Formosa Farm 21 plots (8,400 m2) were established, where 8,959 trees and shrubs were identified. In Maturi Farm, 6,228 woody individuals were identified in 16 plots (6,400 m2). In each one of the permanent plots, two subplots of 1 square meter were established to collect data on herbaceous plants. On this area of 74 m2, monthly measurements were made and 4,250 plants collected along six months (May - December, 2006). a)Woody stratum Table 2.Shannon Index (H´) for woody stratum in two Management Plans Formosa Legal Reserve 2.72 Maturi Legal Reserve 2.27

1992 1.98

1997 2.47

1991 1.77

1992 2.20

1998 2.31 1994 1.62

1999 1.98

2000 2.10

1996 1.10

In Total Area 4,11 In Total Area 2,78

In Coupes Area 3,21 In Coupes Area 2,09

As depicted in Table 2, the values observed for Shannon Index (H`) were higher in the Legal Reserve areas than in the harvested areas of the two sites. Since the measured area in the harvested plots was the same or higher than in the RL areas, it is evident that some reduction of woody species diversity did happen at stand level as a consequence of the management practices applied. However, H` values calculated for the whole management units (i.e. harvested plots + Legal Reserves) are much higher than in the LR areas alone, and H` for the whole set of coupes is nearly the same as in LR. This suggests that harvested areas contribute with a new and different source of variation that was not present in LR, so increasing the woody species diversity of the management unit as a whole. In other words, the diversity found in the management units is higher than that of any of their parts. Table 3 details the number of woody species found in the management units: it is clear that a modest proportion (41 to 61%) of woody species is common to LR and harvested areas. About one fifth of the species (18 to 21%) were found only in the LR areas, indicating that these might have been adversely affected by clear-cut harvest. But a new and big group of woody species appeared only in the harvested areas, in both sites, representing 18 to 39 % of its total richness.

Frans Pareyn, Enrique Riegelhaupt and Maria Auxiliadora Gariglio

192

Table 3. Richness found in two Management Units Woody Species found

MATURI

FORMOSA

in LR and 3 coupes in LR and 2 coupes

9 5

24% 13%

16 7

29% 13%

in LR and 1 coupe

2

5%

42%

11

20%

Only within Legal Reserve Only outside of Legal Reserve

7 15

18% 39%

12 10

21% 18%

TOTAL

38

100%

56

100%

61%

Shannon Index values by themselves do not fully reflect the impact of forest management on woody species diversity, since these cannot account for species substitution that occurs at management unit level. This fact can be perceived only after total species richness and its distribution in Legal Reserves and harvested coupes is analyzed. b. Herbaceous stratum Species richness for herbaceous plants was higher in every harvested area than in the Legal Reserve areas. However, Shannon index values were lower, due to higher dominance of a few species in the coupes. Forest management, as practiced in these two sites, increased richness but diminished diversity of herbaceous stratum, as depicted in Table 4. Table 4. Richness and diversity index in two management units Area Richness H´

LR 13 2.18

1997 19 1.72

1998 25 2.04

2000 22 1.03

LR 17 2.15

1992 14 1.43

1994 18 1.2

1996 19 0.65

7. IMPACTS ON FAUNA 7.1. Native Bees This group, including only solitary and para-social native bees, was selected for a number of reasons: a) it has high species diversity, with 193 species of 79 genera reported in the caatinga; b) bee populations area abundant and occur in almost every site; c) many species are highly specialized regarding the exploration of floral resources, implying that its diversity and abundance may be directly related to diversity and abundance of flowery plants occurring in the site; d) small solitary bees have restricted live areas and short life-cycles, thus showing fast response to local environmental conditions; e) the males of many species can be easily attracted by means of scent baits, allowing for their fast collection and identification;

Environmental Impacts of Caatinga Forest Management - A Study Case f)

193

the nests of many species are conspicuous and permit easy localization of nesting areas and micro-sites

To collect native bees, three field sorties (of six days each one) were made in the rainy and also three in the dry season, at one month intervals. Three collection techniques were used: 100m transects to observe nests in earth and stems; observation of flowering plants in the early morning; and scent baits. Sampling effort was the same in both farms and covered the Legal Reserve Area, the older harvested area and one of the more recently harvested coupes. Species found were 56, of which only 26 common to both farms and 15 were unique to each site. This fact indicates that important variations may exist between near sites, since Formosa and Maturi Farms are just 70 km apart. There were no significant differences between dry and rainy season. More strikingly, eight of the exclusive species were found only in the harvested areas, suggesting that these offer flowery resources quite different from those found in the Legal Reserve areas. The richness was always higher in the Legal Reserve areas, with a decreasing number of species found in the harvested areas along the age series. The number of individual bees was similar in both farms; in some coupes it was higher than in the LR, as shown in Table 5. The short-term impact of harvesting was strongly negative for the diversity of native bees. In the coupes harvested in year 2000 the number of species was drastically reduced in both sites. In older coupes (1999, 1998, 1994 and 1991) the number of species was gradually higher, but never reaching that found in the Legal Reserve areas. Shannon Index values showed a faster recovery pattern, as shown in Figure 10, where one coupe has a value of H` that is higher than the respective Legal Reserve, probably due to higher evenness in one of the coupes. Thus, we conclude that diversity of native bees was recovered during the management cycle and it is also a good indicator of environmental impact of forest management. . Table 5. Species richness and abundance of native bees Farms Areas Individuals Species

FORMOSA Legal Coupe Reserve 1997 172 110 34 20

Coupe 1998 183 7

Coupe 2000 3 1

Total 468 48

MATURI Legal Coupe Reserve 1991 135 58 27 21

Coupe 1994 104 18

Coupe Total 2000 153 450 2 48

In this study, 35 species of flowering plants, mainly climbers, shrubs and herbs, were found to be visited by native bees. Only four tree and nine shrub species were reported as actively foraged, even if 35 woody species occur in the area. This suggests that trees and shrubs may not be of much importance as source of pollen and nectar for native bees, implying that the its diversity and abundance might be more related to the floral supply originated from other plant life forms.

194

Frans Pareyn, Enrique Riegelhaupt and Maria Auxiliadora Gariglio

Figure 10. Shannon Index for native bees in two sites.

7.2. Amphibia and Reptiles (Herpetofauna) Two animal groups of quite diverse habits and adaptations were included in this study. The amphibia (frogs and toads) are dependent of water bodies for their reproduction. Their activity is strongly seasonal, and mostly nocturnal. Reptiles (lizards and snakes) reproduce in terrestrial environments and are more active in diurnal periods, both in rainy and dry seasons.

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This group was selected as impact indicator because it is well known and amply inventoried in caatinga biome, thus allowing for comparisons to be made between the managed sites and other areas.

Figure 11. Species foraged by native bees.

Sampling effort totaled 28 days for each site, spread along 4 months in the rainy season and 4 months during the dry season. Three sampling points were chosen in each Farm (Legal Reserve, old harvested area and newly harvested area). Sampling techniques were: pitfalls observation transects, active search, individual tagging, Sherman and Tomahawk traps and local inhabitants information. The results of this study were striking, both in terms of the species richness and number of individuals either captured or registered: 1,654 specimens were collected, of which 1,170 in Maturí Farm (including 933 amphibia and 237 reptiles), plus 484 in Formosa Farm (443 amphibia and 41 reptiles). Total richness was of 22 species of amphibia (six families) and 31 species of reptiles (corresponding to seven families of lizards, two of snakes, one of amphisbena and one of turtles). As depicted in Figure 12, richness was related to the age of the coupe in Maturi Farm. In Formosa Farm, the Legal Reserve area had lesser richness but greater abundance (16 spp, 46 specimens). One of the harvested sites (coupe 1997, 14 years old) had greater richness and higher abundance (21 spp.; 133 specimens). The lower values corresponded to coupe 1996 (9 years old), with 9 spp. and 25 specimens.

Frans Pareyn, Enrique Riegelhaupt and Maria Auxiliadora Gariglio

196

Figure 12. Richness of herpetofauna in Maturi and Formosa Farms.

The diversity found in these sites suggests that for amphibia, the age of the coupe may not be the main factor governing species richness. It is possible that microhabitat diversity has a more marked effect on the diversity of this group. The list of species found in both Farms represents 46% of all the amphibia (Anura) and 27% of all reptiles presently recorded for the whole Caatinga biome. Its richness is similar or greater than that found in four areas of the PROBIO study and RPPN Serra Almas (Araújo et al., 2005) other well preserved areas located in Conservation Units that were studied by the same team of specialists with the same methodology, as shown in Table 6. This fact proves that forest management of caatinga, as applied in these two cases, did not have a negative impact on local amphibians and reptiles populations. Table 6. Number of species found in different areas of Caatinga biome Group

Caatinga

PROBIO Study (4 sites) 35,000

RPPN Serra Almas 4,800

Maturi Farm

Formosa Farm

Area (ha)

85,000,000

Amphibia

51

100%

29

57%

22

43%

22

43%

20

39%

Lizards

47

100%

26

55%

22

47%

12

26%

10

21%

Anfisbenae

10

100%

1

10%

3

30%

2

20%

----

Serpentss

52

100%

15

29%

14

27%

13

25%

1

2%

Turtles

4

100%

3

75%

----

1

25%

1

25%

Crocodiles

3

100%

1

33%

1

33%

----

Total Reptiles

116

100%

46

40%

40

34%

28

24%

12

10%

Total

167

100%

75

45%

62

37%

50

30%

32

19%

350

350

----

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From the study on herpetofauna it is evident that forest management, as applied in Formosa and Maturí Farms conserved a high level of diversity of amphibia and reptiles, with wide distribution and endemic species found in both sites.

7.3. Mammals Mammals are important controllers of animal populations, and may also play an important role in pollination and seed dispersal processes. Herbivorous mammals can strongly affect plant populations. This group is highly sensitive to environmental perturbations, showing diverse reactions: migration, adaptation, and/or more or less intensive exploitation of altered sites. However, its value as indicator of environmental impacts of forest management is limited, because in the cases of big and medium sized mammals, and also for flying species, their living area is much wider than the area of the managed forest, normally less than 500 hectares. In this study two groups of mammals were included: terrestrial and winged, aiming to provide information for the general public -highly sensitive and speculative in regard of the possible impacts of forest management on iconic species-. Both groups were sampled in the same points as reptiles and amphibians, using the techniques depicted in Table 7. Total sampling effort for terrestrial mammals was 1,840 trap days in the dry season (novdec-jan, 2006) and 3,944 trap.days in the rainy season (mar-apr-may-jun-jul, 2007). To capture bats, mist nets were used, totaling 504 m2.hour in dry season and 98 m2.hour in rainy season. In Maturí Farm 26 species were registered, and 20 in Formosa Farm, of which 19 common to both sites. Twenty of these registers were obtained by direct capture, and six by questionnaires applied to local residents. The location of registers is shown in Table 8. Table 7. Sampling techniques used for mammals Species Small size

Indirect capture Questionnaires, footprints, sightings

Big size

Direct capture Fall traps Sherman and cage traps Fall traps Sherman and cage traps _____________

Winged

Mist nets

Questionnaires

Medium size

Questionnaires, footprints, carcasses, sightings Questionnaires, footprints, carcasses, sightings

In some of the sampling points located in the harvested areas, the number of captures and registers was higher than in the Legal Reserve areas. This does not necessarily mean that harvested areas are richer or offer more ample resources for mammals, because (a) most of the captures correspond to winged mammals (Chyroptera, or bats), which are highly mobile, and (b) the absolute number of captures of terrestrial mammals is low, and so the differences in numbers between sample points might be stochastic.

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Table 8. Number of mammals registered and captured in two managed areas

GROUP terrestrial winged total

Legal Reserve areas 9 23 32

Old harvested coupes 7 44 51

New harvested coupes 11 8 19

Other sites (pond, house, fence) 7 2 9

A surprising fact was that the number of species found in these managed areas was equal or higher than the corresponding number in conservation units (Araújo et al., 2005), as shown in Table 9. Table 9, Number of species found in managed áreas and in Conservation Units

Sites

Maturi Farm , Formosa Farm Ceará State

Serra das Almas Ceará State

Cantidiano Valgueiro e State Park Maurício Dantas Pedra Da Boca Pernambuco State Paraíba State

Terrestrial Winged

15 12

15 7

13 9

7 9

Out of the 15 terrestrial mammal species found in the managed sites, 9 are common to Natural Heritage Private Reserve (NHPR) Serra das Almas; 9 to NHPR Cantidiano Valgueiro and Maurício Dantas; and 4 to State Park Pedra da Boca. Out of the 12 species of Chyroptera, 3 are common to NHPR Serra das Almas; 5 to NHPR Cantidiano Valgueiro and Maurício Dantas; and 5 to State Park Pedra da Boca. Thus, the managed areas contain an important fraction of the mastofauna of these Conservation Units. Only two species of rodents (G. spixii and T. apereoides ) were registered. This scarcity in the managed areas might be due to the presence of domestic animals and/or to hunting by local settlers. Mammals are not the ideal environmental impact indicator group in small areas as the studied FMP, because its presence and abundance may depend more on the conditions prevalent in the surroundings than in the managed areas ―per se‖. However, the results of this study are positive because of the high diversity found.

8. SOILS In a first stage a detailed field survey of soil types was made in both sites. In 700 ha of plain to mildly undulated terrain seven different soil classes were identified, as follows. Petroferric Eutrustox (PLINTOSSOLO PETRICO Concrecionário típico) Plinthic Eutrustox (PLINTOSSOLO ARGILÚVICO Eutrófico típico) Typic Eutrustox (LATOSSOLO VERMELHO AMARELO Eutrófico típico) Typic Plinthustalf (ARGISSOLO AMARELO Eutrófico plíntico) Arenic Haplustult (ARGISSSOLO ACINZENTADO Distrófico fragipânico) Arenic Natrustalf (PLANOSSOLO NÁTRICO Órtico típico)

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Lithic Ustorthent (NEOSSOLO LITÓLICO). Only one of the above soil types (Petroferric Eutrustox) was found in the Legal Reserve area and also in two harvested areas of different ages in Formosa Farm (Coupe1992 and Coupe 1997), allowing for comparisons to be made. Thus, 10 samples of horizon A (0 to18 cm depth) were taken in each one of these three sites. Laboratory tests showed that no significant differences exist in soil properties along the time series, with the only exception of Organic Matter content, as shown in Table 10. No indications of soil compaction or porosity loss were found, since apparent density is the same in harvested coupes and Legal Reserve. Similar values for Cation Exchange Capacity and Base Saturation indicate that fertility and nutrient cycling in the coupes follow the same trend as in the Legal Reserve area. Soil contents of Ca, Mg, K and N as well as conductivity were not statistically different, reinforcing the above conclusion. Table 10. Soil properties in different sampling areas (*)

Area

Time (years)

Organic Matter %

Base Saturation (cmol/dm3)

Legal Reserve

40

2,5b

3,5a

Cation Exchange Capacity (cmol/dm3) 6,9a

T- 1992

13

1,9a

4,3a

T- 1997

8

1,8a 2,1

MEAN

pH (in H2O)

Apparent Density (g/cm3)

5,7a

1,71a

7,9a

5,7a

1,70a

3,6a

7,1a

5,6a

1,79a

3,8

7,3

5,7

1,74

(*) Same letters indicate differences statistically not significant

It can be concluded that the only impact of forest management was a certain reduction of organic matter content in soil upper horizon. No other physical or chemical soil properties were affected. The depth of horizon A was not affected.

9. CONCLUSION This study on the environmental impacts of commercial forest management is the first one in Caatinga biome. A great effort was done to select and test indicators, to adapt research techniques and to set up a framework for future studies that may follow, related to dynamics of vegetal and animal diversity in native forest managed for productive purposes. Regarding forest stocking and productivity, the management practices applied in the studied sites were quite effective, achieving high growth rates and fast stand recovery after clear cut. In fact, measured growth rates in Formosa and Maturí Farms are similar to those observed in other Brazilian forests of humid climates, such as Amazonian and Atlantic high forests. High stand growth rate in caatinga after clear-cut is clearly due to the very high number of stems resulting from vigorous stump sprouting, since diameter increment is low. If the management goal is to produce firewood or any other small-dimension woody product (fencing sticks, small poles, and the like), this short-cycle system (9 to 14 years) is

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advantageous. If the objective is to harvest stakes, poles, or medium sized logs, cutting cycles will be much longer, probably not less than 20 years. However, in this case growth rates will be much lower, meaning that three or four times more area should be managed to harvest the same amount of wood. Regarding plant diversity, it is clear that the management system applied in these two sites increased species richness and total diversity in the management units. In harvested coupes a loss of woody diversity was evident, mainly due to increased dominance of a few species; but Shannon`s index values for the whole set of coupes were similar to those of Legal Reserve areas. This indicates that woody plants diversity in the whole management unit is greater than in any of its components (preserved and harvested areas), since the harvested coupes contribute with an additional source of diversity that is not present in the Legal Reserves. Species richness and abundance of herbaceous stratum in harvested areas was higher than in Legal Reserves, as could be expected after an intervention that virtually eliminated all tree canopies. Regarding animal diversity, the impacts of forest management in these two sites appear to range from strongly negative to positive, depending on the rate and the time after harvest. Native bees are strongly affected by the loss of habitat and nesting sites in the first five to eight years after harvest, but their populations are quite recovered after 10 years. Amphibians and reptiles can thrive in harvested areas as well as in conserved areas, and show impressive diversity in both farms. Mammals are well represented in both sites, but its richness might not be due to the conditions prevailing within the management units. The impact of forest management on soil properties is almost null, as could be expected, since no soil removal was made and all foliage and twigs were left on site during harvest. These results are striking, and quite positive. From a productive perspective, the vigorous regeneration and high growth rate after clear-cutting show that caatinga forest has high productivity and resiliency when managed in short rotation. This system is efficient for firewood production, even if it does not allows for the recovery of original vegetation structure. From an environmental point of view, most indicators are also positive. The original floristic diversity was increased as a consequence of forest management, in the woody stratum, as a result of the ingrowth of pioneer species and regeneration of originally dominant species. Herbaceous flora in the harvested coupes was higher than in Legal Reserves. Vegetal diversity in the management units is today equal to, or higher than in many Conservation Units in the caatinga biome. In comparison with other farms in their vicinity, these managed areas show more forest cover and good connectivity with other conservation areas, acting also as buffer zones and biological corridors. Considering their species richness and abundance, it is evident that forest management units are effective biodiversity conservation units by themselves. However, several questions are yet to be answered: o o o o

Can this high level of wood productivity be sustained in future cycles relying only on stumps sprouting? Is it possible to keep high floristic and faunistic diversity in shorter cycles? Will organic matter content be lower in subsequent cycles? Can these results be extrapolated to greater management units and/or bigger coupes?

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Are these two cases truly representative of the whole caatinga biome?

Some of the above questions will have answers only after many years of research. But even so, the results of this study case demonstrate that it is possible to use caatinga forest resources in an ordered and rational way to supply social demands, keeping their productive capacity and making an important contribution to biodiversity conservation. Thereby, it can be concluded that there is no contradiction but complementation between sustainable use and conservation of this natural resource. The true dilemma faced by caatinga biome is between sustainable use and destruction. If regional demand for wood, firewood and charcoal were to be supplied in the future as it has been during the last fifty years, through land clearing and conversion of caatinga forest to other land uses, the one and only outcome will be the resource destruction. It makes no difference whether land clearing is or is not officially authorized. In cleared areas native vegetation is eliminated, and its recovery after several years of continued utilization for agriculture or grazing is very slow, because of intense soil degradation and depletion of soil seed banks. In face of this reality, caatinga forest management is the most rational, sure and costefficient alternative to attend regional demands for wood and energy. It is also the land use form that can best contribute to biodiversity and landscape conservation, and probably the most cost-efficient alternative to complement the role of Conservation Units.

REFERENCES Araújo, F. Soares de, Rodal, M. J. N. and Barbosa, M.R.de V. (orgs.) Análise das variações da Biodiversidade do Bioma Caatinga. Suporte a estratégias regionais de conservação. Ministério do Meio Ambiente. Biodiversidade 12. Brasília, DF. 2005. 446p. Cardoso, J.M. da Silva, Tabarelli, M., Tavares, M. da Fonseca, Lins, L.V. (orgs.) Biodiversidade da caatinga: áreas e ações prioritárias para a conservação. Ministério do Meio Ambiente. Universidade Federal de Pernambuco. Brasília, DF, 2004. 382p. Conselho Nacional da Reserva da Biosfera da Caatinga. Cenários para o bioma Caatinga. Secretaria de Ciência, Tecnologia e Meio Ambiente. Recife, 2004. 283p. IBGE . Mapa dos Biomas Brasileros, 2004. www.ibge.gov.br Leal, I.R., Tabarelli, M. e Cardoso, J.M. da Silva (eds). Ecologia e Conservação da caatinga. Editora Universitária da UFPE. Recife-PE. 2003. 822p. Probio - Projeto de Conservação e Utilização Sustentável da Diversidade Biológica Brasileira. Subprojeto – Levantamento da Cobertura Vegetal e do Uso do solo do Bioma Caatinga. 2007. http://mapas.mma.gov.br/geodados/brasil/vegetacao/vegetacao2002/caatinga/documentos/rela torio_final.pdf Sampaio, E.V.S.B., Giulietii, A.M.G., Virgínio, J. E Gamarra-Rojas, C.F.L. (eds) Vegetação e Flora da Caatinga. Associação Plantas do Nordeste – APNE, Centro Nordestino de Informações sobre Plantas – CNIP. Recife-PE. 2002. 176p.

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Souza, D.R. de, Souza, A.L. de, Silva, M.L.da and Rodrigues, F.L. Ciclo de corte econômico ótimo em floresta ombrófila densa de terra firme sob manejo florestal sustentável, Amazônia Oriental. Rev. Árvore, vol. 28, no 5, Viçosa, 2004. Velloso, A.L., Sampaio, E.V.S.B., Pareyn, F.G.C. (eds.) Ecorregiões propostas para o Bioma Caatinga. Associação Plantas do Nordeste, Instituto de Conservação Ambiental The Nature Conservancy do Brasil. Recife-PE. 2002. 76p.

In: Forest Management Editor: Steven P. Grossberg

ISBN: 978-1-60692-504-1 © 2009 Nova Science Publishers, Inc.

Chapter 7

FOREST MANAGEMENT WITHIN PROTECTED AREAS: THE SOCIAL PRODUCTION OF NATURE IN THE DADIA FOREST RESERVE, GREECE Tasos Hovardas* University of Cyprus, Cyprus

ABSTRACT Protected areas are usually perceived as natural places devoid of human presence, where nature is let to unfold its developmental potential. Indeed, this is the dominant representation even for timber-dependent areas. Modern notions, which occupy a crucial position in the dominant environmentalist discourse, such as the catch term ‗biodiversity‘, often perpetuate this supposed divide between society and nature. Within the frame of this paper, we will see how forest management in a Greek protected area helped an endangered vulture species recover and surpass viable population sizes. The case study to be presented wishes to elucidate the delicate way in which societal choices are interwoven with dynamics of natural systems in determining outcomes for both the social and the natural realm. We will focus on the Dadia Forest reserve, situated at the north-eastern part of Greece, which has been most known for hosting a remarkable variety of raptor species, including three European vultures. The zoning system that has been implemented since the designation of the protected area in 1980 aimed at the preservation of the nesting and feeding habitat of vulture species. The Allee effect, which is expected to mediate population dynamics of raptor species, including vultures, is connected to both an unstable and a stable equilibrium threshold for population dynamics of vulture species. Through zoning and specialized forest management, the environmental protection regime gradually led to the confinement of individuals of vulture species to the core compartments of the protected area, which actually was a milestone in the reconfiguration of vulture population sizes from unstable towards stable equilibria. Three decades after the Dadia Forest Reserve has been established, local attitudes towards environmental conservation have changed dramatically, together with land-use patterns and vulture numbers. Locals no longer resist environmental management initiatives but are proud of their area being among the most famous ecotourism destinations in Greece. *

[email protected]

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Tasos Hovardas Visitors come to Dadia to observe from a Bird Observatory vultures feeding on carcasses on the Vulture Feeding Table, which has been landscaped in the protected area to provide food supplement to vultures. Indeed, many residents are employed in conservation or ecotourism related jobs. Interestingly, the population size of the Black Vulture, an endangered vulture species in Europe found formerly only in Dadia and the region of Extremadura in Spain, seems to have exceeded the carrying capacity of the Dadia forest; a number of individuals migrated recently to neighbouring forested sites of Bulgaria.

1. INTRODUCTION 1.1. Forest Management and Changing Environmental Values Despite the fact that forestry introduced the concept of sustainability (Wiersum, 1995), achieving sustainable outcomes within an economic system concentrated on short-term gains remained always a challenge for a long-term endeavour like forest management (Perry, 1998). During the last few decades, forestry professionals came to realize that increasing productivity was in clash with shifting forest values (Xu and Bengston, 1997). Changing demands of modern societies comply with a widened scope of forest management (Farrell et al., 2000). For instance, there is a broad public opposition to clear-cutting, while socially acceptable forestry attends to scenic beauty and serves wilderness needs (Ribe, 2006). Indeed, these attitudes are pronounced among rural residents too (Marsden et al., 2003; Selvik, 2004; Bengston et al., 2005; O‘Brien, 2006). Elands et al. (2004) reported that the majority of local people in 16 rural communities they sampled in Europe do not regard forestry as a major future development option, principally due to negative association with employment opportunities. The response of forest managers has been to replace intensive forestry with the ecosystem management approach, which addresses calls for biodiversity conservation. From rapid site capture by even-aged crop trees, silvicultural techniques changed over to restore the diversity of undisturbed forests. In this vain, sustainable forestry emphasizes biodiversity and a naturalistic version of forest management, which, among other things, favors the conversion of formerly exploited forest sites to mixed forests (Zerbe, 2002; Spiecker, 2003). Indeed, naturalistic silviculture can produce economically efficiently wood and at the same time facilitate nature conservation by supporting biodiversity at various scales (Parviainen and Frank, 2003). New functions pursued include habitat continuity for species requiring large trees, age class variety accompanied by vertical and horizontal heterogeneity and future sources of large dead wood (Perry, 1998). In the European context, forestry is especially affected by the creation of the Natura 2000 network. This is an extended, European-wide reserve system based on the Birds Protection Directive (79/1409/EEC) and the Habitats Directive (92/43/EEC), which have to be integrated into national legislation. Out of 200 habitat types included in the initiative, approximately one-third can be classified as forest habitats (Weber and Christophersen, 2002). Since its introduction in 1997, the aim has been to create a coherent network of different habitat types throughout Europe by the year 2007. The recent enlargement of the European Community shifted the completion of the enterprise in time, since societies and economies in transition of the new member states will need a considerable interval to accommodate. Natura 2000

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imposes new formal restrictions upon local and regional land and resource use within ecologically significant areas. Despite the current acceptance of environmentalist accounts among rural people, no arrangements were made for public involvement during the initiation of the process, which led in most cases to severe conflicts in Natura 2000 sites. Forest policy in Europe for long neglected the social systems within which forest practices occur (Hiedanpää, 2005). Even if forest legislation necessitated the consideration of social impacts when forest policies are planned, in practice, both economic and ecological implications are taken into account, whereas social aspects are not weighed to an analogous extent. The primary reason for this deficiency is that environmental planners and practitioners lack the competence to identify social structures and the social implications of policy actions (Hiedanpää, 2005). Contemporary planning addressed this concern by enriching the decision-making process with various social actors (Straede and Helles, 2000; Aasetre, 2006). This integration led to the democratization of forest management that was previously dominated by the professional bureaucrats (Aasetre, 2006).

1.2. Forest Management within Protected Areas Protected areas are usually perceived as natural places devoid of human presence, where nature is let to unfold its developmental potential. Indeed, this is the dominant representation even for timber-dependent areas. Environmental non-governmental organizations and authorities tend to see nature within protected areas as something ‗out there‘, separated from humankind, which has pivotal implications on the way forest policy is configured (Nygren, 2000). Such dualist accounts promote the attitude that protected areas should be left as undisturbed as possible. In this regard, human activities are considered as a threat to the reserve‘s pristine wilderness. If a protected area is equated with a supposed ‗wilderness‘ reserve, local people residing within its borders do not match with the representation of ‗pristine‘ nature; the consequence is that their rights on the land and their images are delegitimized (Robbins, 2004). Rural residents, who have acted to produce the supposedly ‗wild‘ landscape that powerful outsiders seek to preserve (Robbins, 2004), are treated in a paternalistic manner by outreach campaigns to be taught how to manage their land sustainably (Nygren, 2004). Recent developments acknowledged the potential contribution of local knowledge systems in forest management. Clapp (2004) sees environmental organizations, authorities, and local people in ongoing processes of negotiation as necessary parts of a pluralist future in resource peripheries. In this configuration, the acknowledgement of social difference is a prerequisite. Hayter (2003) conceptualizes the contested representation of land-use rights, including an appreciation of ecosystem functions next to consumptive uses, as a process of continuous ‗remapping‘. Remapping in forestry can be seen as a social mechanism for managing the aftermath of resource depletion, and for beginning to acknowledge alternatives to industrial resource extraction. Remapping is both a political and a technical process, in which resource inventories are improved, new values are explicitly acknowledged, and geographical information systems designed to visualize that knowledge (Clapp, 2004). However, these approaches tend to de-contextualize local cultures and present them as totally compatible with forest management regimes (Robbins, 2004). This supposed harmony

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obviously stands in sharp contrast to park-people conflicts. Rural people feel cheated by an external and scientific hegemonic naturalism that reinstates the human-nature divide by the dichotomy between humanised nature and ‗virgin‘ nature (Buller, 2004; Reser and Bentrupperbäumer, 2005). In many cases, rural opposition to environmental agendas is in itself not an anti-environmental movement, but a contemporary effort of marginalized groups to identify sources of economic, political, and social loss, and symbols of local identity and power (Rikoon, 2006). After all, struggles over forests are both about control and representations of land: τhe choice among sustainable land-use practices is not simply between pristine wilderness and destructive human use, but between different kinds of uses and different forms of control (Nygren, 2004). To counter local reactions, ecotourism is developed, which can generate a new source of revenue to compensate local people for income lost due to the implementation of forest management measures (Hovardas, 1999; Ioras et al., 2001). Despite the fact that ecotourism advocates justly criticise mass tourism for fake images, there is an aspect of ecotourism that remains most often unnoticed and could be characterized as providing a fake image itself. Namely, it is not simply ‗untouched‘ nature what ecotourists encounter within protected areas; before consumed, the ecotourism product has to be itself produced in terms of facilities for interpretation and enacting of ecotourism activities as well as attractions for visitors to encounter (Hovardas and Korfiatis, 2008). Quite paradoxically, by the time the ecotourism product is produced, it can no longer be described by adjectives such as ‗pristine‘, ‗wild‘ or ‗virgin‘. This apparent contradiction brings us to land-use change within forested protected areas, where the primary source of revenue changes from timber extraction to services. That is why among the predominant concerns is to mitigate what could be annoying for the tourism gaze (Clapp, 2004). In a nutshell, people are initially excluded (e.g. prohibition of primary sector activities) only to return later as visitors (e.g. development of ecotourism activities) (Bonta, 2005; Hovardas, 2005). It is in this come-back that the land-use change becomes evident. In any case, the sealing of processes that apparently produced the ecotourism product may have crucial consequences for the formation of local identities (Van Rekom and Go, 2006) and local involvement in forest management. Through such a sealing, the local community may become just another exhibit of the ecotourism experience (Wearing and Wearing, 1999; Robbins, 2004; Hovardas, 2005; Che, 2006).

2. OVERVIEW Within the frame of this paper, we will see how forest management in a Greek protected area helped an endangered vulture species recover and surpass viable population sizes. We will focus on the Dadia Forest reserve, situated at the north-eastern part of Greece, which has been most known for hosting a remarkable variety of raptor species, including three European vultures. Among them, the black vulture (Aegypius monachus) features as the symbolic species of the region and an ecotourism attraction. The case study to be presented wishes to elucidate the delicate way in which societal choices are interwoven with dynamics of natural systems in determining outcomes for both the social and the natural realm. Such an endeavour has always been challenging, since it presupposes a reconstruction of the local environmental

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history in a way that will present the interplay of natural and social forces as a new, emergent event (Fall, 2002; Robbins, 2004). The question to be addressed is: How did forest managers in Dadia succeed in recovering the black vulture population?

3. THE DADIA FOREST RESERVE 3.1. Protected Area Designation The study area is situated in north-eastern Greece (longitude 26000‘ to 26019‘, latitude 40 59‘ to 41015‘). The forest in the region of Dadia is public. Development schemes funded by the World Bank and the Greek government were about to promote in the late 1970s the intensification of forest production, the clearing of deciduous oak forests and reforestation with fast-growing pines. In 1979, a report prepared by the Dutch ornithologist Ben Hallmann for IUCN/WWF activated the Greek Government to establish the Dadia Forest Reserve by a Presidential Decree the following year. The reserve was also included in the Natura 2000 sites proposed in Greece. The protected area extends in the middle part of Evros Prefecture, just next to the Greek–Turkish border (figure 1). The reserve is composed of two core areas with a total surface of 7.258 ha and a buffer zone covering 31.273 ha. There are strict prescriptions set for core areas; only scientific research and forest management practices to advance biodiversity conservation are allowed. The buffer zone involves a variety of land uses under the rubric of sustainability, for instance, ecotourism development. Dadia is most known for its raptor fauna; thirty-six out of thirty-eight European raptor species can be observed in the reserve. The conservation of the black vulture (Aegypius monachus) is the central subject of forest management in the region (Adamakopoulos et al., 1995; Poirazidis et al., 2004). 0

Figure 1. The Dadia Forest Reserve.

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3.2. Climatic Conditions and Vegetation The area is hilly, with an altitude between 10 and 650 meters. Temperatures range from -19 to 400C and the mean annual rainfall varies between 556 and 916mm (Adamakopoulos et al., 1995). Northern winds transform the climate from sub-Mediterranean in lower altitudes to continental towards higher altitudes. This intense continental character, only a short distance away from the Aegean Sea, enables the area to host species, which in other parts of the Mediterranean either are not found at all or are located at much higher altitudes. The most characteristic example is black pine (Pinus nigra), which can be found in Dadia in a lower altitude than anywhere else in Greece (Triantakonstantis et al., 2006). Forests are dominated by Aegean pine (Pinus brutia) and black pine, oaks (Quercus frainetto, Q. Cerris, Q. pubescens) or a mixture. The two cores have 85% cover of pinewoods and mixed pine-oak woods and are of great importance as nesting sites for the black vulture (Poirazidis et al., 2004). Forest occupies more than 70% of the area (Triantakonstantis et al., 2006). Forest openings and agricultural land cover 9% and 16%, respectively, while urban areas amount to less than 1%.

3.3. Land-Use Trends Since 1945, there has been a consistent reforestation rate, while forest growth was significantly larger after park designation than before (Triantakonstantis et al., 2006). The success of the forest management regime is exemplified by the fact that after park designation, reforestation is no longer related to slope. Specifically, in the period before the establishment of the reserve, reforestation occurred in higher slopes, because logging activities were unregulated and such activities were more practical and economically beneficial at lower slopes. The regulation of logging activities after park designation throughout the region, irrespective of slope, indicates that in this period the correlation between slope and forest growth disappeared. Regarding further land-use trends, there is a concern about forest openings, which are important as hunting biotopes for raptors. Trends since park designation show an increased conversion of agricultural lands and forest openings to forest.

3.4. Landscape The Dadia Forest Reserve is characterized by a diversified landscape (Kati et al., 2003). Traditional activities, such as the use of fire, livestock grazing, small-scale logging, and small-scale agriculture have generated a species-rich highly heterogeneous patchwork of habitats. Human presence in the study area is not intense (Poirazidis et al., 2004). Habitations, basic paved roads and agricultural land have not affected black vulture breeding negatively during the last few decades. An exception to this has been the expansion of the forest road network (unpaved roads), especially in the buffer zone.

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3.5. Forest Management A special management plan (Adamakopoulos et al., 1995) and a pilot monitoring plan (Poirazidis et al., 2002) are currently in practice, targeting the biodiversity of the reserve and particularly focused on raptor species of conservation concern. Some of the management policies put in practice are: the provision of vulture food supplement in a feeding table that has been landscaped in the big core of the study area; prohibition of hunting and woodcutting and the control of tourism in the core areas; and the control of all human activities around the bird nests in the buffer zone (Kati et al., 2003). One of the main measures that have been proposed for the conservation of raptors is the maintenance of an open tree canopy of the pine forest and the maintenance of pine wood clearings in the core area in order to maintain the foraging habitat of several raptor species. This will be realized through selective woodcutting, the enhancement of livestock grazing, and the reintroduction of natural herbivore populations such as deer (Adamakopoulos et al., 1995). The management plan also proposes to conserve rural mosaics with hedges.

3.6. Local Reaction to the Forest Management Regime Initially, the establishment of the protection regime stood in sharp contradistinction to the main source of local employment, which was, at that time, forestry. Indeed, the abolishment of forestry in the cores of the protected area has been the primary source of local reaction against environmental conservation measures. This negative stance gradually shifted to an acceptance of the environmental conservation regime principally due to the economic expectations of rural people coupled with ecotourism development (Svoronou and Holden, 2005; Hovardas and Stamou, 2006a). WWF-Greece has launched since the 1980s a series of campaigns to raise the environmental concern of rural residents. For instance, on the Annual Birds' Day, locals in Dadia together with other people in various places all over the world celebrate birds as a common heritage to take care of. Ecotourism was developed in Dadia since 1985 to counterbalance the negative effects of nature conservation on rural residents' income. The number of ecotourists increased sharply in time and infrastructure was gradually expanded to cover the rising demand (Hovardas, 2005).

3.7. Ecotourism Development The first period of ecotourism development corresponds to the years 1985–1996, when basic infrastructure of ecotourism was constructed; the second period refers to a four-year interval from 1997 to 2000, when existing infrastructure was extended to meet increasing demand; the last period covers the years 2001–2004, when new infrastructure was constructed or provided in Dadia (Hovardas, 2005). The vulture feeding table in Dadia, which was landscaped in the big core of the protected area, serves as the hotspot of the ecotourism activity; it is from the bird observatory that visitors can encounter wildlife, namely three vulture species feeding on carcasses transported to Dadia from all over the prefecture. Given the potential to observe the black vulture, the griffon vulture (Gyps fulvus), and the egyptian vulture (Neophron percnopterus) in the vulture feeding table, Dadia hosted lastly more than

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50,000 visitors. Ecotourism development seems to have annulled outmigration trends in Dadia, which is still the primary reason for the depopulation of the Evros Prefecture.

4. FOREST MANAGEMENT FOR THE CONSERVATION OF THE BLACK VULTURE (AEGYPIUS MONACHUS) The black vulture is the largest bird of prey (up to 12 kg) in the western Palearctic (Poirazidis et al., 2004). The European breeding population of this scavenger has been estimated between 1450 and 1477 pairs, of which approximately 80% occur in Spain (Tewes et al., 2004). Greece is the only south-eastern European country holding a breeding population. Black vulture is considered a globally endangered species, vulnerable in Europe and endangered in Greece. The breeding population of this large scavenger showed a sharp decline through the last century, reaching extinction in most of its former range (Carrete and Donázar, 2005). The reasons for this decline have been breeding habitat loss and a decrease of food availability paired with changes in livestock-raising practices (Hallmann, 1998). The population of the species in Dadia increased steadily since 1987, when a feeding station was established. While the population in 1980 amounted to no more than 10 breeding pairs, the maximum number of birds recently counted in the reserve is around 90 birds, including more than 25 breeding pairs (Vlachos et al., 1999; Skartsi, 2002). Maps of probability of occurrence for the nest sites of black vultures showed that nests are very likely to fall within the cores of the reserve (Poirazidis et al., 2004). Poirazidis et al. (2004) reported that the optimal nesting habitat of the black vulture in Dadia is mature trees surrounded by openings or with low height vegetation located in steep slopes. Topography and human disturbance work in concert to influence nest site selection (Donázar et al., 2002). Areas with steep slopes far from human disturbance constitute frequently the black vulture‘s breeding sites. Air currents facilitate the black vulture‘s take off and as the currents are most frequently available on hillsides, this would explain the choice of these sites for the construction of nests (Morán-López et al., 2005). Vegetation models in Dadia showed that black vultures may not be confined to pure pine forests only, but could also nest in mixed pine-oak stands or in broadleaf forests with isolated mature pines (Poirazidis et al., 2004). In Spain, black vultures were found to use mainly mature oaks as nesting sites (Donázar et al., 2002). It is highly probable that the key priority for the black vulture is the occurrence of mature nest-trees, and not the type of nest-tree or the surrounding forest (Fargallo et al., 1998). The large size of the bird and the nest makes the existence of trees of adequate size more important than tree type or density (Morán-López et al., 2005). The specific vegetation type of black vulture‘s nesting habitat resulted from past forest fires and the preservation of its microhabitat requires intense human activity. To periodically monitor the gradual canopy closure of the forest around the nest sites, Poirazidis et al. (2002) suggested that livestock grazing could also preserve forest openness and reduce the risk of fires. However, Poirazidis et al. (2004) suggested that special care should be taken regarding timing and methods, since populations of forest-breeding raptors are sensitive to forest management practices and habitat changes (Donázar et al., 2002; Morán-López et al., 2005).

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Since there are suitable breeding habitats also in the buffer zone (southeast of the large core), special care is taken in the long-term management in these forests. According to Poirazidis et al. (2004), forest management and black vulture conservation in this case can coexist. Road access in significant parts of this area is controlled using bars managed by the Forest Service (Poirazidis et al., 2004). Further, forestry activities are restricted in areas where black vultures breed, and avoided during the core breeding season, namely between January and August, since this was one of the major reasons for breeding failure (Donázar et al., 2002; Morán-López et al., 2005). The species, which is at the top of the food web as consumer of carcasses of livestock and wild animals (Morán-López et al., 2005), may search through enormous land surfaces because of its large body size and energetic requirements and unpredictability of its food resources (Carrete and Donázar, 2005). However, breeding birds are tied to the colony yearround, behaving as central-place foragers, which are obliged to return every day to their nest at the colony. Hence, its foraging habitat selection pattern would be a result of a trade-off between the quality of the different patches, i.e. food-rich and food-poor habitats, and the distance at which they are located, i.e. low vs. high flight cost (Carrete and Donázar, 2005). Therefore, creating or maintaining forest openings is of primary importance for the conservation of the foraging habitat of the species (Gavashelishvili and McGrady, 2006). Increments in food-searching distances can have fitness consequences in terms of reducing offspring quantity, even affecting large-scale population trends (Carrete and Donázar, 2005).

5. ZONING IN THE DADIA FOREST RESERVE Predictions based on island biogeographic theory (MacArthur and Wilson, 1967) that smaller and more isolated parks will lose more species than those that are big or connected (Newmark, 1996; Wood, 2000), led to the notions of ‗buffer zone‘ (areas surrounding nuclear reserves) and ‗corridor‘ (connection between two protected areas). Indeed, research on the extinction debt of protected areas, namely the number of still-extant species whose habitat needs are no longer met, shows how the size and degree of isolation of a protected area can determine vulnerability to decline or extirpation of metapopulations (Carroll et al., 2003). Determining effective sizes of reserves seems to be still a puzzling exercise, since current protected area networks included within the Natura 2000 system may be not efficient to ensure favourable conservation status for bird species, which necessitates additional largescale conservation measures (Godet et al., 2007). The buffer zone enlarges the effective size of core areas and provides an external protection of the core (Crumpacker, 1998). Especially for areas with a long history of forestry, creating buffer zones around woodland key habitats (i.e. small areas that host or potentially host red-listed species) helps dealing with fragmentation substantially, since it minimizes negative edge effects and promotes characteristics of natural forests in managed stands to decrease isolation and enhance dispersal possibilities (Aune et al., 2005). If so, the network of woodland key habitats could potentially function as a metapopulation system where temporary extinction in some patches is compensated by colonization from other. Zoning in Dadia enabled black vultures to face ‗ecological traps‘. The term describes the situation in which a bird‘s choice of nesting habitat leads to nest failure because of a recent

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anthropogenic change in the environment that break the normal cue-habitat quality correlations (Gates and Gysel, 1978; Schlaepfer et al., 2002). Thus, a trap arises when an organism is constrained by its evolutionary past to make a mistake, although suitable conditions or adaptive choices remain available elsewhere. For instance, in undisturbed forests, vegetational heterogeneity might normally provide good foraging opportunities and protection against predators. The sudden increase in forest edges as a result of human activities (e.g. road network expansion) represents an ecological trap because the evolved preferences of the birds lead them to seek the heterogeneous habitat now encountered primarily along edges. However, that choice is no longer adaptive because of the unusually high density and diversity of predators found along edges (Schlaepfer et al., 2002). By providing food supplement in the vulture feeding table and conserving the nesting and foraging habitat of black vultures, birds were confined within the core areas of the Dadia Forest Reserve. Since population sizes are a function of place, this led to an increase in the population size of the species, despite the fact that individual numbers for some period after designation remained the same (figure 2). Obviously, this had an additional, crucial effect: if the species in the 1980s had been close to the threshold of a viable population size, the forest management regime shifted black vultures from unstable to stable equilibria. This will be exemplified by the presentation of the Allee effect in the next chapter. The very interesting feature in the case of Dadia is that the conservation of the black vulture has been mediated not by enlarging the reserve or creating corridors; it was core areas, which through the intervention of the Allee pattern facilitated the population size of the black vulture to recover.

Figure 2. If a number of individuals (A) is concentrated in lesser space (B), then the population size is increased.

6. ALLEE EFFECTS Allee effects are strongly related to the extinction vulnerability of populations and are gradually becoming acknowledged by both theoretically oriented and applied ecologists (Berec et al., 2006). Allee effects occur whenever fitness of an individual in a small or sparse population decreases as the population size also declines (Berec et al., 2006). Allee effects

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have been reported for large carnivores (Hurford et al., 2006), and birds including vultures (Deygout et al., 2007). The numerous factors associated with such effects can be classified into three main categories (de Roos et al., 2003; Robinet et al., 2007; Penteriani et al., 2008): genetic inbreeding and loss of heterozygosity; demographic stochasticity including sex-ratio fluctuations; reduction in cooperative interactions among conspecifics when there are fewer individuals. The latter can include sexual reproduction, i.e. shortage of receptive mate encounters during the mating period when density is too low, foraging efficiency, and increased risk of predation. In Allee effects, positive density-dependent mechanisms overpower negative densitydependent ones (e.g. intraspecific competition) at low population sizes. Allee effects are characterized by a hump-shaped relationship between per capita growth rates and population sizes (figure 3). The birth and death rate curves cross at two points, which signify two different types of population equilibria. At relatively low population sizes, departure from Nt 1 causes centrifugal trends: populations that drop below this critical threshold go extinct (death rate higher than birth rate), whereas increased density leads again away from Nt1 towards larger population sizes (birth rate higher than death rate). Such a threshold value is the population dynamical manifestation of an unstable equilibrium (Van Kooten et al., 2005). The situation is reversed at larger population sizes, where departure from Nt2 generates centripetal trends that restore density at the point of departure. Therefore, Nt2 is characterized as a stable equilibrium threshold.

Figure 3. The Allee effect.

Since two or more Allee effects can occur simultaneously in the same population, estimating the value of the extinction threshold resulting from the simultaneous presence of several Allee effects could be crucial for the management of threatened populations (Berec et al., 2006). As it can be impossible to handle the complexity inherent in estimating Allee thresholds and to fine-tune management around this value, management of populations with Allee effects should be risk aversive. The establishment of the Dadia Forest Reserve was such a case for the conservation of the black vulture, which presents a cooperative foraging behaviour. In Dadia, vultures faced a sharp decline in food availability, primarily due to a

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substantial decline in animal husbandry as well as decrease of the total surface of forest openings, which are of primordial importance for the maintenance of their foraging habitat. This was coupled with an increase in the density of forest road network, which increased the levels of annoyance significantly, as well as hunting and illegal poisoning. Probably the fate of another vulture species that was formerly present in Dadia but became extinct, namely the bearded vulture (Gypaetus barbatus), could have been earmarked by such a coupling of multiple Allee effects.

7. THE SOCIAL PRODUCTION OF PROTECTED AREAS: WHAT DO FOREST RESERVES LOOK LIKE? Much modern environmental thinking stems from the assumption that boundaries between nature and culture can be easily defined: this is the origin of the belief in an intact nature (Haila and Levins, 1992; Robbins, 2004). Fall (2002) claims that rather than creating unproblematic ‗natural‘ spaces, the definition of boundaries within protected areas formally reifies the modernist duality of nature and culture, leading to perceptual and practical inconsistencies among protected area managers. The latter face the difficult challenge of maintaining boundaries that protect and sustain these areas, while working to erase or diminish the negative effects of the same boundaries (Knight and Landres, 1998). In this direction, managers need to tightly control nature in order to maintain natural conditions that supposedly have existed before they were disturbed by human activities (Wood, 2000). Logging of any kind – whether clear-cut for timber production or single tree selection for nesting habitat conservation– is an unnatural event in the history of a forest (Perry, 1998). The present paper builds on the call of Robbins (2004), to shift our focus from the ‗destruction‘ of nature towards its ‗production‘. ‗Nature‘, ‗environment‘, and ‗forests‘ are socially produced both as physical realities as well as mental representations and practices, which configure social relationships among people and social groups (Castree, 1997; Yliskylä-Peuralahti, 2003; Bonta, 2005). Indeed, it is through representation by maps that a reserve comes to existence in the first place (Bonta, 2005) and this leads to a reconfiguration of space (figure 4). The reference to both a material and a representational dimension of production is contradistinguished with post-modern positions, which attempt to reduce nature to an artefact of human culture (Schroeder, 2007). Rather than adopting a dualistic approach to address the human-nature relationship, which opposes the two sides, or a monistic approach, which collapses the natural realm into the human or vice versa, we subscribe to a dialectical position. This sees humanity and nature as simultaneously shaping and being shaped by the other, while each maintaining a measure of autonomy (Evanoff, 2005). It is in this dialectical perspective that human societies are seen in relational terms as both constituting and being constituted by the environments they inhabit. The fact that humans and nature interrelate reciprocally suggests that knowledge, value, and ethics develop out of interactions with a materially real world existing outside of human consciousness (Evanoff, 2005). The discursive component of social production, namely social construction, is conceptualized as the meanings attached to ‗nature‘, ‗environment‘, ‗forest‘, etc, which we come to accept through social interaction (Corbett, 2006). That is not to say that ‗nature‘, ‗environment‘, ‗forest‘ do not really exist; they do exist and they are out there

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independent of us and of our definition of them (ontological assumption). However, there is no cognitive appropriation of ‗nature‘, ‗environment‘, ‗forest‘, which could provide an objective, socially and culturally unmediated access to some type of essence of these notions (Robbins, 2004). Namely, their cognitive appropriation cannot be but socially and culturally embedded (epistemological assumption).

Figure 4. The delineation of the Dadia Forest Reserve led to a reconfiguration of space.

8. AN ALTERNATIVE CONCEPTUALIZATION OF PROTECTED AREAS IN RESOURCE EXTRACTION REGIONS Three decades after the Dadia Forest Reserve has been established, local attitudes towards environmental conservation have changed dramatically, together with land-use patterns and vulture numbers. Locals no longer resist environmental management initiatives but are proud of their area being among the most famous ecotourism destinations in Greece. Visitors come to Dadia to observe from a Bird Observatory vultures feeding on carcasses on the Vulture Feeding Table, which has been landscaped in the protected area to provide food supplement to vultures. Indeed, many residents are employed in conservation or ecotourism related jobs. In line with results from other rural areas, it seems that the environmentalist discourse has widely diffused in the local community (Papageorgiou et al., 2005; Hovardas

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and Korfiatis, 2008; Korfiatis et al., 2008; Natori and Chenoweth, 2008). However, this is not always accompanied by a wider appreciation of environmentalist claims, such as quality of life issues. It could be that the local endorsement of environmentalism is confined to a mere financial expectation due to ecotourism development (Hovardas and Stamou, 2006a) or just to pursue rural people‘s interests (Nygren, 2004). To face this apparent deficiency, messages promoted through ecotourism and environmental education in the Dadia Forest Reserve should focus on the interplay between society and nature — for instance, on conservation aims, on monitoring, and on the coexistence and interdependence of local communities and the natural environment (Hovardas and Stamou, 2006b). Therefore, visitor information and outreach programs should not be confined to mere descriptions of biodiversity and conservation measures applied within protected areas; instead, they should address the fact that human interventions are integral to any kind of environmental conservation initiative (Hovardas 1999). This is much more compatible with developing critical thinking to support environmental literacy and create a politically informed public which could be able to handle complex issues, including choices that cut-across the natural and the social realm. Recent initiatives in the study area, such as the construction of pipelines for oil and natural gas that will run from Bulgaria through the Evros Prefecture (e.g. the Burgas-Alexandroupoli pipeline for oil transport), call urgently for such a critical and politically informed rural citizenry. This critical stance should build on issues of social production as outlined in this paper. Forest management under the rubric of a dualist approach of the relationship between society and nature strived to epitomize ‗intact‘ nature within protected areas (figure 5a). In this case, local communities should comply with pre-determined decisions taken in a top-down process. In an alternative configuration, forested protected areas can be conceptualized as negotiated land-use change, where all interest groups should not simply be consulted but also take part in formulating the objectives of forest management (figure 5b). In this regard, protected areas could offer a means of ‗experimentation‘, where potential alternative forms of land uses could be assessed in order to be ‗exported‘ out of their borders. For an illustration of this ‗experimentation‘ potential, Poirazidis et al. (2004) reported that integrating traditional activities in forest management is necessary for the conservation of the nesting and foraging habitat of the black vulture in Dadia. Additionally, Kati and Sekercioglu (2006) showed that the rural mosaics, defined as small fields and pastures separated by natural vegetation of thick hedgerows and tree lines, were the most diverse and important sites for conserving bird fauna in Dadia. This is in line with former research, which reported that cultivated areas are generally known to play a fundamental role in maintaining diversity in the Mediterranean region for various taxa (Suarez-Seoane et al., 2002; Grill and Cleary, 2003). These findings provide support for the European Common Agriculture Policy towards the maintenance of the rural mosaic landscape as an important bird habitat in the Mediterranean region (Kati and Sekercioglu, 2006).

9. CONCLUSION Through specialized forest management, the environmental protection regime in Dadia gradually led to the confinement of individuals of vulture species to the core compartments of

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Figure 5. An alternative conceptualization of protected areas.

the protected area, which actually was a milestone in the reconfiguration of vulture population sizes from unstable towards stable equilibria. Under the mediation of the Allee effect, this shift toward viable population sizes is the emergent situation, which can not be attributed solely to the natural or the social realm but needs both of them to take effect. Zoning has enabled this merging of natural and social forces that led to the recovery of the black vulture. In this vein, the Dadia Forest Reserve is an exemplary case of an ‗eco-social complex‘ (Haila, 1998), which elucidates how human activity and natural processes interact to produce novel events. Interestingly, the population size of the species, found formerly only in Dadia and the region of Extremadura in Spain, seems to have exceeded the carrying capacity of the Dadia forest; it has been reported that a number of individuals migrated recently to neighbouring forested sites of Bulgaria (Kostas Poirazidis, personal communication). The forest management regime succeeded in facing a risk situation concerning black vulture conservation, but this has been accompanied by the emergence of two new risks. First, even though forests in the Mediterranean Basin have adapted to the periodic fires which facilitate regeneration (Robbins, 2004), a forest fire in Dadia would be catastrophic for both nature conservation and ecotourism. Quite paradoxically, it is exactly to these fires that the creation of the nesting habitat of the black vulture is attributed to (Poirazidis et al., 2004). Further, ecotourism development seems to create a gradually increasing demand of tourism services, which could also have a negative impact on natural (Lukăc and Hrsăk, 2005; MoránLópez et al., 2005) and social carrying capacities (Hovardas, 2005). Once again, these new risks demand a consistent focus on the merging of social and natural dimensions within the frame of social production for forest management to succeed.

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In: Forest Management Editor: Steven P. Grossberg

ISBN: 978-1-60692-504-1 © 2009 Nova Science Publishers, Inc.

Chapter 8

A COMPARISON OF FOREST RESOURCES IN SELECTED JURISDICTIONS OF NORTH AMERICA AND EUROPE: SOME IMPLICATIONS FOR MACRO-SUSTAINABILITY ASSESSMENT Gordon M. Hickey Department of Natural Resource Sciences Faculty of Agricultural and Environmental Sciences McGill University, Canada

ABSTRACT Decision-making regarding sustainable forest resource allocation and protection requires suitable and comparable information on the state of forest resources and the human use of forests. It is here that sustainability assessment has become a recognized approach to better informing decision makers on the social, economic and environmental dimensions of forest management. This chapter compares macro-level forest resource statistics in 24 jurisdictions of North America and Europe to enable the implications of resource variability to be considered and discussed in the context of sustainability assessment. The results highlight certain similarities and differences at the macro-level of forest management in each jurisdiction that will affect the nature of sustainability assessment at the regional, sub-regional and nation/state/province levels. These differences will affect management goals, sustainability indicator selection and the subsequent scale and intensity of monitoring and reporting required to ensure informed decision-making. They will also affect the level of public sector investment in monitoring, assessment and performance reporting to the community, resulting in variability in forestry-related data quality and quantity in different jurisdictions. Despite this, increasing globalization and internationalization has precipitated a demand for standardization and comparability of sustainability indicators and associated sustainability assessments between jurisdictions. There is, therefore, a need for researchers to build on the issues presented in this chapter by further considering how forest resource-related monitoring and information reporting in different jurisdictions differ; and what the implications are for assessing sustainable forest management at an inter-jurisdictional level.

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1. INTRODUCTION Decision-making regarding sustainable forest resource allocation and protection requires suitable and comparable information on the state of forest resources and the human use of forests. It is here that sustainability assessment has become a recognized approach to better informing decision makers on the social, economic and environmental dimensions of forest management. Sustainability assessment is considered to be a vital component of sustainable development, simultaneously spanning economic, social and environmental factors. It is recognized that sustainable development requires long-term, comprehensive assessments of international and national policy programmes against resource sustainability targets and criteria (United Nations 1996; Organisation for Economic Co-operation and Development (OECD) 2004; European Commission 2005). In the forest sector, the most common approach to macro-sustainability assessment is to monitor performance against internationally agreed criteria and indicators of sustainable forest management (see Hickey and Innes 2008), with regular (generally five-yearly) ‗State of the Forests‘ reporting to the public (see, for example, Ministerial Conference on the Protection of Forests in Europe (MCPFE) 2007; Canadian Forest Service 2007; Montreal Process Implementation Group of Australia 2008). While these reports are often insightful and can be excellent points of reference for forestry statistics, significant difficulties arise in the interpretation of the data being presented, and in creating meaning in the ultimate assessment of sustainability, particularly at the inter-jurisdictional level. One reason for this problem is that sustainable forest management (SFM) means different things to different people, at different scales of management and at different time periods. The characteristics of the forests and landscape resources in any given jurisdiction will also impact on the definition of SFM, the implementation of government strategies, and the subsequent nature, scale and intensity of monitoring conducted (Hickey 2008). This chapter compares macro-level forest resource statistics in 24 jurisdictions of North America and Europe to enable the implications of resource variability to be considered and discussed in the context of sustainability assessment.

2. METHODOLOGY 2.1. Jurisdictions The jurisdictions listed in Table 1 were selected based on six criteria, described by Hickey et al. (2006), to ensure that each had a similar institutional capacity to implement SFM. To assist comparison and discussion, data from the selected jurisdictions in Canada, USA or Europe were sometimes aggregated.

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Table 1. Selected jurisdictions North American State / Province Western North Eastern North America America Alberta Maine British Columbia Michigan California Minnesota Oregon New York Washington Ontario Quebec Wisconsin

European Nation State Northern Europe

Western Europe

Eastern Europe

Denmark Finland Norway Sweden United Kingdom

Austria Belgium Germany Netherlands Switzerland

Czech Republic Poland

2.2. Selection of Variables The variables for this study were drawn from a wide range of publications comparing international, regional and national-level forestry related statistics. When conducting international comparisons, the OECD (1994) presented three criteria for ‗ideal‘ variable selection: • • •

Relevance to policy and utility for users; o Representative, simple, show trends, responsive, international, national significance; Analytically sound; and o Theoretically well founded, based in international standards / consensus, linkages; Measurable. o Readily available (reasonable cost), adequately documented, regularly updated.

The variables selected for this study met these selection criteria. These variables were then used to describe and compare general social, environmental and economic conditions related to forestry at the national level in Europe and the state and provincial levels in North America. There was no single method of standardization when comparing the variables across jurisdictions because, in many cases, the available data were subject to different definitions and measurement methodologies in different nations, states and provinces. An important observation that arises from the current study is that data from the European jurisdictions are generally standardized through various international organizations; however the forestry related data for the states and provinces in North America are often inconsistent. It was therefore necessary to be clear about the data source and reference year when interpreting the data (see Annex 1). It is also important to note that the data presented in this study are historical, with reference years ranging between 1996 and 2003. Therefore, the comparisons should not be interpreted by the reader as ‗current‘, particularly the socio-economic data which rely on $US conversions that are not indicative of 2009 currency exchange rates.

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2.3. Comparative Analysis: Pattern Matching/Logical Analysis The pattern matching technique described by Hickey (2004a) was used for data presentation; description and analysis (see also Miles and Huberman 1984). A comparative analysis was conducted using state and provincial data for North America and national level data for Europe. It was acknowledged that the jurisdictions cannot be comparable in every context. Every effort was made to obtain comparable data to enable a broad interpretation of the wider operating environment of forestry spanning the selected jurisdictions in the study. Although this information was often incomplete (especially at the North American state and province level) some data were available and these have been the focus of this study. The analysis used graphs and tables to display the data in a form that facilitated interpretive analyses.

3. RESULTS AND DISCUSSION 3.1. Key Macro-Statistics for Selected Jurisdictions Table 2 presents data on six socio-economic variables for each jurisdiction, as follows: total population (M), population density (n/km2), rural population (%), Gross Domestic Product (GDP)/Gross State Product (GSP) per capita (‗000 $US), unemployment rate (%) and economic growth measured as real annual GDP/GSP change (%). These indicators have been used to provide approximations of the socio-economic climate in the nominated jurisdictions to the extent that they can be related to forests. They have also been used for inter-jurisdiction comparisons of socio-economic conditions by a range of international and national agencies [e.g. the Food and Agriculture Organization (FAO); Statistics Canada; United States Bureau of Economic Analysis; Organisation for Economic Co-operation and Development (OECD); The World Bank; and The World Resources Institute (WRI)]. 3.1.1. Population Characteristics Figure 1(a) shows that the population in the European jurisdictions was generally higher than in the North American jurisdictions. Germany (82.2 M) had the largest total population in 1999 followed by the UK (59.0 M), Poland (38.7 M) and California (33.9 M). The lowest populations in the sample were Maine (1.3 M), Alberta (3.1 M) and Oregon (3.4 M). Norway (4.4 M) had the lowest population of the European jurisdictions. These differences provide important context for sustainability assessments because the population characteristics in a particular jurisdiction will affect the level of demand being placed on its natural resources (WCED 1987). This subsequently affects the nature and intensity of the societal responses designed to ensure sustainable development (Hickey 2008).

Table 2. Socio-economic data for jurisdictions in North America and Europe Jurisdiction

Population

Population density

Rural population

GDP/GSP per capita

Real annual GDP change

Unemployment

Alberta BC Ontario Quebec CANADA* California Maine Michigan Minnesota New York Oregon Washington Wisconsin USA* Austria Belgium Czech Republic Denmark Finland Germany Netherlands Norway Poland Sweden Switzerland UK EUROPE*

(M) 3.1b 4.1 b 12.1 b 7.5 b 6.7 33.9 b 1.3 b 9.9 b 4.9 b 19.0 b 3.4 b 5.9 b 5.4 b 10.5 8.2 a 10.6 a 10.3 a 5.3 a 5.2 a 82.2 a 15.7 a 4.4 a 38.7 a 8.9 a 7.4 a 59.0 a 21.3

(n/km2) 4.8 b 4.5 b 13.1 b 5.5 b 7.0 83.8 b 15.9 b 67.5 b 23.9 b 155.2 b 13.8 b 34.2 b 38.1 b 54.1 98.8 a 322.3 a 132.8 a 124.5 a 17.0 a 235.3 a 463.9 a 14.5 a 127.3 a 21.6 a 185.7 a 244.1 a 165.7

(%) 32.9 c 40.8 c 19.4 c 23.7 c 29.2 3.3 d 59.8 d 17.8 d 29.2 d 7.9 d 28.8 d 16.7 d 40.0 d 25.4 35.4 a 3.0 a 33.9 a 14.4 a 35.4 a 12.7 a 10.7 a 26.0 a 34.8 a 16.7 a 37.7 a 10.7 a 22.6

(‗000 $US) 32.0 b 21.2 b 24.8 b 20.4 b 24.6 37.1 a 27.2 a 31.3 a 36.2 a 41.5 a 33.1 a 36.4 a 31.7 a 34.3 23.3 c 22.1 c 5.6 c 29.7 c 23.4 c 22.5 c 23.9 c 37.2 c 4.6 c 24.7 c 34.0 c 24.3 c 22.9

(%) 4.0 d 2.0 d 3.7 d 3.6 d 3.3 7.3 b 2.2 b 2.4 b 5.2 b 6.1 b 8.1 b 2.0 b 2.6 b 4.5 0.7 d 0.7 d 2.5 d 1.5 d 1.6 d 0.2 d 0.1 d 2.0 d 1.2 d 1.7 d -0.2 d 1.5 d 1.1

(%) 5.5 d 8.2 d 6.8 d 8.4 d 7.2 6.6 e 4.5 e 6.2 e 4.4 e 6.3 e 7.6 e 6.7 e 5.4 e 6.0 3.6 c 6.6 c 8.2 c 4.3 c 9.2 c 7.7 c 2.4 c 3.6 c 18.2 c 4.9 c 2.6 c 5.0 c 6.3

*These values are the average for the associated sample jurisdictions. Reference years: a 1999; b 2000; c 2001; d 2002; e 2003.

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Figure 1. Comparison of selected population characteristics For the selected jurisdictions the average population (a) was 15258.75, the average population density (b) was 102.00 people per km2 and the average proportion of the population classified as rural (c) was 24.65%.

Figure 1(b) clearly shows that population densities in the European jurisdictions were also higher on average than the North American jurisdictions. Netherlands (463.9/km2) had the highest population density followed by Belgium (322.3/km2), the UK (244.1/km2) and Germany (235.3/km2). The Canadian jurisdictions (Alberta, British Columbia (BC), Quebec and Ontario) had the lowest population densities of all jurisdictions ( 35,000 $US) and that Poland (4,600 $US) and the Czech Republic (5,600 $US) had the lowest GDP per capita in the same period. Data on GDP/GSP and GDP/GSP per capita are used by governments to assess and monitor their policies for spending, employment, trade, taxes, manufacturing, and products. As a result, the prevailing economic performance of a jurisdiction will influence the decision-making priorities of its government. Therefore, the status afforded to the outcome of sustainability assessments in decision-making can differ dramatically between and within jurisdictions through time, depending on the economic climate. Unemployment is another macro-economic indicator that is often used to describe economic conditions within a particular jurisdiction. The number of people of working age without a job is usually expressed as an unemployment rate. Figure 3 shows that in 2001 the unemployment levels in the European jurisdictions varied between the Netherlands (2.1%) and Finland (9.2%) with Poland (18.2%) the exception. The North American jurisdictions showed less variability with unemployment levels between Minnesota (4.1% in 2003) and Quebec (8.2% in 2002).

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Figure 2. Plot of real annual change in GDP/GSP (%) against annual GDP/GSP per capita ($US) in selected jurisdictions. The vertical dotted line represents the average GDP/GSP per capita ($27,000) and the horizontal dotted line represents the average annual GDP/GSP change (2.7%) for the jurisdictions.

Figure 3. Unemployment levels (2002). The average unemployment level for the sample was 6.37%.

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When unemployment exceeds ‗acceptable‘ levels governments can be expected to react to the political realities. In these situations, societal definitions of sustainability will change towards a greater focus on achieving socio-economic outcomes, sometimes at the expense of environmental objectives. This suggests that in those countries with sustained high or unacceptable unemployment levels (e.g. Poland) there would be a different political focus on the role of sustainability assessments in informing strategic decision-making than in those jurisdictions with a low sustained unemployment level (e.g. the Netherlands).

3.2. Extent of Forest Resources in Selected Jurisdictions In order to compare the jurisdictions with respect to forest resources and landscape conditions, five variables were selected: total land area (M ha), forest and woodland area (%), forest area per capita (ha/n), forest cover distribution by type (%), and inland (fresh) water area (%). These variables are consistent with recent approaches designed to compare and document statistics on forest-related resources internationally (e.g., the Global Forest Resources Assessment). By comparing the data related to these variables, jurisdictions with similar forest resource characteristics are highlighted. When interpreting these data it was recognized that there were some inconsistencies in the definitions and collection methods used for each category. 3.2.1. Forest Area Figure 4 shows the total land area (M ha) plotted against the total forest and woodland area (%) for the selected jurisdictions. In general, both land area and forest area (as a % of total land area) were highest in the North American jurisdictions. The Canadian jurisdictions of Quebec, BC, Ontario and Alberta and the European jurisdiction of Sweden were above the sample average for both variables. Overall, relative forest cover was highest in Maine (89.6%) and Finland (72%). Denmark (10.7%), the Netherlands (11.1%) and the UK (11.6%) had the lowest percentage forest cover of the selected jurisdictions. Total land area was also generally higher in the North American jurisdictions than in Europe. Quebec, BC and Ontario were the largest jurisdictions (>90 M ha), while the Netherlands, Belgium, Switzerland and Denmark were the smallest (89%) and also had the highest average size for NIPF holdings (107.8 ha). In the USA sample, the highest proportion of publicly owned forests were found in Oregon (64%) and California (58%). The average size of NIPF holdings in the USA jurisdictions was 14.6 ha. In Europe, Switzerland (89%), the Czech Republic (84%) and Poland (83%) had the highest proportion of publicly owned forest. The average size of NIPF holdings in the European sample (19.8 ha) was similar to the USA. Overall the jurisdictions in Canada had about twice the area of publicly owned forest and roughly six times the average size of NIPF holdings when compared to the jurisdictions in the USA or Europe. The proportion of forest publicly owned in Maine (6%) was the lowest overall while Norway (14%), Sweden (17%) and Austria (18%) had low levels of public ownership relative to the other jurisdictions. With regard to the average size of NIPF holdings Switzerland (1.3 ha), Poland (1.8 ha) and Belgium (2.5 ha) were the smallest of the sample. Land tenure is a key issue that affects land use decisions within a particular jurisdiction. In order to understand the different approaches to, and perceived needs for, sustainability assessments in different jurisdictions, the distribution of ownership must be clearly understood because it often becomes politically contentious when decision-makers implement policy objectives over a wide range of ownership structures (see Hickey et al. 2007). This will affect the monitoring and information reporting deemed necessary to assess the state of forest resources (Hickey et al. 2005; Hickey et al. 2006; Hickey et al. 2007). Land ownership also has implications for implementing and regulating legislation, codes of practice, conservation programmes, research and development agendas, and non-timber forest values (e.g. recreation, water management, etc).

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Figure 7. Plot of public forest ownership (%) against the average size of NIPF holdings (ha) in selected jurisdictions. The vertical dotted line represents the average public ownership (52.13%) and the horizontal dotted line represents the average NIPF area (32.41ha) for the jurisdictions.

While the extent of public ownership of forest landholdings frames the scope for forest policy making, NIPF holdings are also a significant component of SFM, especially in Europe and the USA where more than half of the wood supply comes from these forests (Rametsteiner 2002). Birch (1996) noted that the proportion of forest ownerships with written plans increases with the size of the ownership in the USA. This will directly affect the availability of standardized data and information for sustainability assessments (see Hickey et al. 2005).

3.4. Endangered Species in Selected Jurisdictions The number of species classified as ‗endangered‘ is an aspect of the forest environment that has implications for biodiversity and sustainability assessment. Figure 8 shows endangered species data for the selected jurisdictions and it is clear that there were more endangered species listed in North America than Europe. California had the greatest number of endangered species (299) with the other Pacific jurisdictions of North America including BC (48), Oregon (54) and Washington (41) also recording relatively high numbers. In the European jurisdictions Germany (21) and Poland (20) had the highest number of endangered species while Denmark, Norway, the Netherlands and Finland had the fewest (