Development of an inventory system for non-timber functions of forests in the frame of management inventories: the case of Greece

Transcription

1 Development of an inventory system for non-timber functions of forests in the frame of management inventories: the case of Greece Inaugural-Dissertation zur Erlangung der Doktorwürde der Forstwissenschaftlichen Fakultät der Albert-Ludwigs-Universität Freiburg i. Brsg. vorgelegt von Spyridon Galatsidas Freiburg im Breisgau 2001

2 Dekan: Prof. Dr. Dr. h.c. G. Becker Referent: Prof. Dr. Dr. h.c. D. R. Pelz Korreferent: Prof. Dr. J. Huss - ii -

3 Table of contents Table of contents...iii Acknowledgments...iv List of tables...v List of figures...vii Abstract... x 1. Introduction and theses objectives State-of-the-art in forest management inventories and inventories of non-timber functions5 2.1 The functions of forests Current trends in forest policy and their implications to management inventories The conditions in Greece The Greek forests Forest management inventories in Greece Inventories of non-timber functions The ecosystem approach in forest inventory Forest ecosystems and their characteristics Ecological land classification as a tool for describing ecosystems Developing a forest management inventory for the non-timber functions Basic characteristics of the inventory system Systematization of information required to describe non-timber functions Assigning a meaning to factor values with respect to a non-timber function Inventory design for non-timber functions and establishment of measurement procedures Deriving interrelationships among ecosystem factors Introduction Factor analysis and Principal components analysis Cluster analysis Testing the inventory system Introduction and description of the area Implementation of the inventory for non-timber functions Inventory results Water percolation potential conditions Water percolation actual conditions Erosion danger potential conditions Erosion danger actual conditions Incorporation of the inventory results into forest management planning Discussion Summary Ausführliche Zusammenfassung References Annex 1: Data recording sheet for the internal factors (Plot data) Annex 2: Variables inventoried and their evaluation regarding water percolation and erosion danger iii -

4 Acknowledgments The present theses was financed by the European Commission under the contract FAIR- BM , in the frame of the Program Training and Mobility of Researchers Training Through Research. Many thanks to the unknown referees who evaluated positively the proposed research project and to the European Commission for making available the necessary financial means. I wish to thank my supervisor Prof. Dr. Dr. h. c. D. R. Pelz, director of the Department of Forest Biometry, for his guidance and constructive discussions during my work at the department. I would like also to thank Prof. Dr. J. Huss, director of the Institute of Silviculture for accepting to be co-referee of my theses. Special thanks go to Dr. S. Gatzojannis, researcher at the Forest Research Institute of Thessaloniki, Greece, for giving the first ideas for this theses and for his continuous encouragement. My thanks go also to Dr. P. Stefanidis, Associate Professor at the Department of Mountainous Water Management and Control, University of Thessaloniki, for valuable discussions on subjects related to hydrology, erosion control and water percolation; Dr. K. Kalabokidis, Assistant Professor of Environmental cartography at the Aegean University, for the constructive discussions and his contribution to the clarification of variables related to the herbs layer of forest stands; Dr. A. Tsionzis, soil specialist, researcher of the Forest Research Institute of Thessaloniki for undertaking the soil survey in the testing area. To Dr. M. Sapounzis, being responsible for the field inventory in the testing area, as well as to the members of the field crew I ought special thanks for their engagement and their helpful remarks concerning practical issues of the inventory. For their encouragement and cooperation, I wish to thank my colleagues in the Department of Forest Biometry H. Binder, Dr. R. Burk, M. Fay, P. Lübbers, P. Obergföll, O. Rau, M. Scheuber, R. Scoz and Dr. E. Zenner. Mrs. E. Meyer, secretary of the department and Mr. J. Rohde, technician have supported me in various ways and I would like also to thank them. - iv -

5 List of tables Table 1: A classification of non-timber forest functions. Table 2: Area covered and percentage per land use type in Greece. Table 3: Ownership status of the Greek forest lands. Table 4: Forest area covered by tree species and percentage of the Greek forest lands. Table 5: Forest cover percentage per altitude zone. Table 6: Key for the interpretation of the evaluation results for non-timber forest functions (adapted from WULLSCHLEGER, 1982). Table 7: Classification of the values of "Soil depth" and "Land use type" into classes with respect to the erosion protection function Table 8: Calculation of the water percolation potential class through the synthesis of the values and relative weights of the external factors and variables (adapted from PELZ ET AL, 2000). Table 9: Distribution of the land cover types in the forest of Thessaloniki Table 10: Main tree species and their coverage in the forest of Thessaloniki. Table 11: Weights of the variables of the external factors for the water percolation function in the forest of Thessaloniki. Table 12: Summarized values of the inventoried variables (external factors). Table 13: Correlation coefficients between variables (external factors). Table 14: Factor (PC) loadings for each original variable on the rotated solution. Table 15: Evaluation of the ability of the stands to percolate water through the synthesis of the values of internal factors-variables and the respective weights. Table 16: Descriptive statistics of the inventoried variables (internal factors). Table 17: Correlation coefficients between inventoried variables(internal factors). Table 18: Factor (PC) loadings for each variable on the rotated solution. Table 19: Descriptive statistics of the inventoried variables (external factors for the erosion function). Table 20: Correlation coefficients between the inventoried variables (external factors for the erosion function). Table 21: Factor loading for each variable (external factors for the erosion function) in the rotated PC solution. - v -

6 Table 22: Descriptive statistics of the inventoried variables (internal factors) for the erosion function. Table 23: Correlation coefficients between inventoried variables (internal factors) for the erosion function. Table 24: Factor (PC) loadings of the variables of the internal factors for the erosion function. - vi -

7 List of figures Figure 1: Relative importance of the functions of forests in Europe (UN-ECE/FAO, 1992). Figure 2: System of external factors for the non-timber functions. Figure 3: System of internal factors for the non-timber functions Figure 4: Interval scale for the assessment of the significance of factor values (adapted from GATZOJANNIS, 1984). Figure 5: Calculation of weighted average of class values within a land unit. Figure 6: Conformity of the systematic allocation of plots with the cells of the internal and the ones of the external factors. Figure 7: The inventory and evaluation procedure for the non-timber functions. Figure 8: diagram of the eigenvalues in order of magnitude (scree plot). Figure 9: Geometric interpretation of Principal components analysis (adapted from BORTZ 1999). Figure 10: Map of the testing area. The forest extends NE from Thessaloniki and the main streams mouth towards the city. The main watersheds are numbered with Latin numbers. Figure 11a, b: Valuation results of rock and soil depth for water percolation. Figure 11c, d: Valuation results of soil texture and humus content of soil for water percolation. Figure 11e: Valuation results of "land cover structure" for water percolation. Figure 11f, g: Valuation results of aspect and slope for water percolation. Figure 11h, i: Valuation results of land use type and road density for water percolation. Figure 11j, k: Valuation results of hydrological network density and shape of watershed. Figure 11l: Valuation results of existence of torrential phenomena for water percolation. Figure 12: Evaluation results of the external factors of water percolation function applying weighting techniques Figure 13: Dendrogram of cluster analysis of the land units (external factors) in the forest of Thessaloniki (horizontal axis measures rescaled Euclidean distances between clusters). Figure 14: Spatial distribution of the five clusters of land units with similar characteristics regarding water percolation. - vii -

8 Figure 15a, b, c, d: Valuation results of Forest cover percentage & land cover structure, stand structure type, canopy closure and development stage for the actual conditions of the water percolation function. Figure 15e, f, g, h: Valuation results of the variables vertical structure, shrubs-regeneration, herbs and downed dead biomass for the actual conditions of the water percolation function. Figure 15e, f, g, h: Valuation results of the variables stand origin/management system and harvesting conditions for the actual conditions of the water percolation function. Figure 16: Evaluation results for the internal factors of the water percolation function applying weighting techniques. Figure 17: Dendrogram of cluster analysis of the land units (internal factors) in the forest of Thessaloniki. Figure 18: Cluster membership of land units (internal factors of the water percolation function) for the four options in the number of clusters. Figure 19: Calculated factor (principal components) values of land units for the water percolation function. Figure 20: Valuation results of rock (erodibility), soil depth, soil texture and humus content of soil for the erosion danger. Figure 21: Valuation results of soil moisture, soil compactness, climate for the erosion danger function. Figure 22: Valuation results of vegetation zone and land cover structure for the erosion danger function. Figure 23: Valuation results of aspect and slope for the erosion danger function. Figure 24: Valuation results of altitude zone and land use type for the erosion danger function. Figure 25: Valuation results of road density and density of hydrological network for the erosion danger function. Figure 26: Valuation results of shape of watershed and existence of torrential phenomena for the erosion danger function. Figure 27: Dendrogram of the cluster analysis for the land units of the external factors and erosion function in the forest of Thessaloniki. Figure 28: Spatial distribution of the five clusters of land units with similar characteristics regarding erosion danger. - viii -

9 Figure 29: Valuation results of forest cover percentage & land cover type, stand structure type, species composition and canopy closure for the actual conditions of the erosion danger function. Figure 30: Valuation results of stand development stage, vertical structure of stand, cover of shrubs-regeneration and cover & height of herbs for the actual conditions of the erosion danger function. Figure 31: Valuation results of downed dead biomass, stand origin/management system and harvesting conditions for the actual conditions of the erosion danger function. Figure 32: Dendrogram of land units agglomeration for the internal factor variables and the erosion function. Figure 33: Cluster membership of land units (internal factors for the erosion function) for the two options on the number of clusters. Figure 34: Calculated factor values (principal components) of the land units for the erosion function. Figure 35: Stands of three compartments of the forest where similar measures regarding the water percolation function should be applied. Figure 36: Stands of three compartments of the forest where similar measures regarding erosion protection should be applied. - ix -

10 Abstract The development of an inventory and evaluation methodology for non-timber functions of forests in the frame of management inventories is the main objective of the theses. Two systems of factors that can comprehensively describe forest ecosystems and their functions have been developed. The system of external factors comprises the major ecosystem components and provides for evaluation of ecosystem potentials with respect to a function. The system of internal factors includes structural attributes of forest stands and provides for the evaluation of the actual stand conditions regarding a function. Respective variables derived from both systems have been inventoried in the forest of Thessaloniki, Greece to test the evaluation of the functions water percolation and protection against erosion. Principal components analysis has been applied to derive interrelations among variables and reduce the number of variables to deal with. A consecutive cluster analysis resulted to homogeneous groups of land units and forest stands, for which similar management prescriptions as well as silvicultural treatments could be drawn. Keywords: Forest management inventory, Non-timber functions, Principal components analysis, Cluster analysis, Greece. - x -

11 1. Introduction and theses objectives Forests provide a variety of goods and services to the society. Goods include wood (timber, firewood and other wood products), fodder, fruits, shelter and other non-wood products. Services comprise employment, recreation, hunting, grazing, protection of human settlements, protection of soil and water, a variety of habitats for wildlife, moderation of carbon and climate. From this wide spectrum of goods and services, timber production had dominated the interests of people and its regulation has been the main objective of forest management for centuries. In the west European countries forest management methods to regulate timber production are dated back to the 18 th century (SPEIDEL, 1972; KURTH, 1994). Forest management inventories are, consequently, timber oriented. Wood related variables are measured in the course of traditional inventories, usually repeated at 10 years intervals, to determine wood stocking and increment. This information constitutes the basis for detailed management planning to ensure sustainable yield of timber. The role of the non-timber functions of forest has also long been recognized and lead to incorporation of principal concepts of disciplines such as ecology, soil science and hydrology, genetics, wildlife and range management into forest management regimes. Also the economic prosperity which has increased leisure in the last decades, has raised the importance of the recreation function of forest. All these have contributed in the formulation of the concept of multipurpose management of forests. Realization of multipurpose management has been done through spatial separation of the forest functions mainly by setting aside (out of the timber production process) areas of specific non-timber value (national parks, natural monuments, special protected areas etc.). Under multipurpose management timber production is still the main function under consideration and the other functions are treated as limitations to the production of wood. It is thought that once timber supply issues are resolved, provisions for the other functions would suffice to sustain the uses and maintain the productivity of forest lands (FEDKIW, no year of publication stated). Forest management plans, therefore, take also into account environmental and recreational concerns of the society and direct stand treatments so as to fulfill these concerns. Emphasis is given to outputs of goods and services rather to stewardship of the forests (FRANKIN, 1997). From the viewpoint of management inventories non-timber related information is collected in a descriptive way, as verbal notes (BINDER, 1997), which does not permit a further exploitation of the data. To the reasons for that should be counted the qualitative nature of the involved variables and the lack of production functions (PELZ, 1995). In the last decades, growing environmental problems such as climate change and the greenhouse effect, the loss of biological diversity, large scale deforestation and - 1 -

12 desertification have shown that nature recognizes no borders between countries and that regional forest management decisions can have implications on scales broader than the forest itself. These problems have also changed the public attitude and increased pressure for protection of the forests as natural ecosystems. Recognizing the global character of environmental problems, the international community established the World Commission on Environment and Development, which published its report Our Common Future in The central concept of this report is that of sustainable development, defined as a development that meets the needs of the present without compromising the ability of future generations to meet their own needs. The work of this Commission provided major underpinning for the UN Conference on Environment and Development which took place in Rio de Janeiro in 1992 and resulted in a program of actions to achieve sustainable development in the 21 st century (Agenda 21). In this conference, about 170 participating states have also adopted a "Statement of Forest Principles" on the management, conservation and sustainable development of all types of forests. The statement of forest principles recognizes the "...vital role of all types of forests in maintaining the ecological processes and balance at the local, national, regional and global levels..." and that all types of forests "...embody complex and unique ecological processes which are the basis of their present and potential capacity to provide resources to satisfy human needs as well as environmental values...", points out that "Forestry issues should be examined in a holistic and balanced manner within the overall context of environment and development, taking into consideration the multiple functions and uses of forests..." and calls for a promotion of methodologies that provide a comprehensive assessment of economic and non-economic values of forest goods and services. The statement of forest principles constitutes a turning point in forest policy bringing sustainable development and management of forests in the center of global environmental policies. It has also launched a number of regional initiatives to refine the forest principles and develop criteria and indicators for sustainable management of forests at regional levels. In Europe, the new concept of sustainable management was officially formulated in the 2 nd Ministerial Conference on the Protection of Forests, which took place in Helsinki in The 1 st resolution of this conference defines sustainable management as "the stewardship and use of forests and forest lands in such a way, and at a rate, that maintains their biodiversity, productivity, regeneration capacity, vitality and their potential to fulfill, now and in the future, relevant ecological, economic and social functions, at local, national, and global levels, and that does not cause damage to other ecosystems". According to this definition, the principle of sustainability is expanded to include the hole forest ecosystem. Forest ecosystems should be managed in a way that maintains and - 2 -

13 enhances their values as sources of biodiversity, producers of wood and other commodities, habitats for wildlife, sinks for carbon, moderators of water cycle and climate. The ecological and protective functions of forests come to the fore. They are no more limitations to timber production but they constitute central objectives of forest management planning. A second outcome of the definition of sustainable management is the shift from focusing on a particular unit of land to a broader view. Forest ecosystems are not closed systems but they interact with neighboring ecosystems exchanging materials and energy in an evolving in time and space process (FORMAN AND GORDON, 1986). As first priority is the maintenance of healthy and stable ecosystems, desired forest conditions should not only be considered at stand level but also at ecosystem and landscape levels. These changes in forest policy have certain implications to forest management inventories. The aim of forest management inventory is now to provide the necessary information for organizing and planning the whole spectrum of forest functions. What ecosystems are and how they function should be understand, analyzed and incorporated into short and long term planning (BARTUSKA, 1994). Inventory of entire ecosystems implies defining ecosystems in operational terms (AVERS ET AL., 1994), i.e. defining which components comprise an ecosystem and which relationships exist among these components enabling the manifestation of a non-timber function. A successful inventory should provide information about the major ecosystem components which affect a forest function and determine the limits within which these components can be treated in favor of the function without jeopardizing ecosystem stability. Such an inventory at forest enterprise level is lacking today, although various parameters relating to non-timber functions are collected during traditional management inventories or other specialized inventories. The need to cover the information requirements posed to forest management planning by the recent changes in forest policy as described above, makes the development of an inventory system for the non-timber functions necessary. The aim of the present study is to develop a management inventory system for the nontimber functions of forests, which will cover the information needs of forest management planning at the enterprise level. That is, an inventory system that will provide quantitative information for the current conditions of the forest ecosystem, its development trends and for the limits within which the non-timber functions of ecosystem can be sustained. The first objective to be achieved in the development of the inventory system will be to determine the information needed for managing non-timber functions. This implies research to define what forest ecosystems are and how they work and select the appropriate variables that describe forest ecosystems and the functions they perform

14 A second objective of the theses is to find a combination of methods of multivariate statistics that can integrate site specific information and provide for collective evaluation of multiple observations. In particular, methods that can reduce the dimensionality of multivariate observations as well as methods that can derive similarities among observations are to be considered. Although the inventory system would be generally applicable in any country, certain parts of the system will be developed considering the conditions of the forest ecosystems in Greece. The reasons for selecting Greece are firstly that approaches to inventory nontimber functions are lacking, though the need for such a system is recognized (GATZOJANNIS, 1988) and secondly an effort in this direction has recently been realized in the frame of a research project in which the author has also worked. An approach to inventory and monitor non-timber functions has been developed in the frame of the research project Development and Harmonization of Monitoring Systems for Forest Resources Management in Europe financed by the European Union. Important parts of this approach have been adopted but also improved and further developed in the present work. The selection of Greece has posed an additional objective. To investigate the currently applied forest management inventory systems in Greece, define gaps in the information collected in view of the information needs of the non-timber functions and examine the possibilities to integrate non-timber inventories to the traditional management inventories in Greece. Finally, the objectives of the theses include the testing of the inventory system for the nontimber functions in the forest of Thessaloniki in order to draw conclusions concerning practical aspects of the inventory procedures and evaluate critically the results of the developed methodology

15 2. State-of-the-art in forest management inventories and inventories of non-timber functions 2.1 The functions of forests Forest functions are the "bioecological impacts and the socioeconomic services of the forest" (BRÜNIG AND MAYER, 1980). DIETERICH (1953) is referred to have introduced the term forest functions in forestry science (WULLSCHLEGER, 1982). He has recognized three functions of the forests: the production of raw materials (used by the people utilization function), the protection function and the recreation function (the last two called services of the forests). To these three major categories, a fourth has been added after human became conscious of the global influences of the environmental degradation: the environmental functions of the forests. The four major categories can be broken down to a great variety of specific functions. An indicative list of forest functions compiled from ANON. (1982), WULLSCHLEGER (1982), FAO (1995), GOTTLE AND SÈNE (1997), and FÜHRER (2000) is presented in table 1. WULLSCHLEGER (1982) argues that the term function is not quite successful to characterize this variety and proposes the terms impacts (effects), tasks and services of the forests as more appropriate for specific cases. The term can be also confused with "ecosystem function" and "landscape function". In both these cases "function" has the meaning of ecological process and it refers to the ecological process itself. Forest functions on the other hand are not pure ecological processes (e.g. recreation) and additionally the term "function" refers to the results (effects) of ecological processes and not to the processes themselves. Nevertheless, the term forest function has been adopted in the international literature and it is also used here. Some basic characteristics of the forest functions have been described from WULLSCHLEGER (1982), GATZOJANNIS (1988) and PELZ (1995) and are discussed next: - 5 -

16 Table 1: A classification of non-timber forest functions. Function Production functions Protection functions Recreation functions Environmental functions Product or Service Timber, firewood, other wood products, fodder, resin, cork, fruits, mushrooms, aromatic and medicinal plants, game animals, etc. Protection of human settlements from natural hazards (rockfalls, torrents, landslides, avalanches, wind, etc.) and from annoyance (noise, exhaust gases, dust, etc.). Protection of soil against water and wind erosion. Protection of water resources. Recovering in leisure time, nature experience, landscape enjoyment, environmental education. Maintenance of flora and fauna, their biotopes and their diversity. Moderation of local and global climate, contribution to water cycle, air quality and CO 2 sequestration. Forest functions are overlapping. The same forest area can as a general rule fulfil more functions, i.e. produce wood and other products, protect soil from erosion, be visited for recreation and contribute to local climate. That is, forest functions are to a degree complementary. Competition among functions arises as soon as money is to be invested for the organization of their "production". Forest functions exist irrespective of human utilization. The fact that some functions are of greater importance for humans and actions are implemented to organize them does not mean that the other functions cease to exist. A forest has the potential to fulfil all the functions regardless of whether humans make use of a function or not. Forest functions can change over space and time. The degree at which a function is present in a forest changes due to alterations in the forest itself or because of amendments in the importance that humans assign to each function. Forest functions, except for production functions, are difficult to quantify. While production functions can be expressed in physical terms (i.e. cubic meters of wood, kilograms of fodder, resin or cork, numbers of game animals), there is no physical unit to measure how much protection from natural hazards or against erosion a forest offers, how much it contributes to the maintenance of biodiversity or to the water cycle. According to the Forest Resources Assessment 1990 (FAO, 1995) wood production remains still the most important function of forests, but non-timber functions are assuming increasing importance in European countries. Seven forest functions have been classified by experts in each country into three classes of low, medium and high importance; the results are shown in figure 1 and the associated table. Although wide variations among countries exist, the figures are indicative of the relative importance of the seven functions in Europe. Wood production assumes the highest rating, followed by hunting and recreation

17 Percent of total area High importance Medium importance Low importance Wood production Protection Water Grazing Hunting Nature conservation Recreation High importance Medium importance Low importance Figure 1: Relative importance of the functions of forests in Europe (UN- ECE/FAO, 1992). 2.2 Current trends in forest policy and their implications to management inventories Aim of the investigation in this chapter is to illustrate recent changes in international forestry policy, to analyze these changes with respect to the implications they have on management inventories and derive the information that the modern forest policy demands from management inventories. The United Nations Conference on Environment and Development which took place in Rio de Janeiro in 1992 was the starting point for the development of new concepts in global forest policy. The Rio declaration reflects the current level of international agreement concerning the values and priorities in environmental management and development. A holistic approach that incorporates environmental, social and economic criteria in decision making processes is proposed for a sustainable development. The seek of a balance between economic development and protection of the environment was formulated in the statement of forest principles (UNCED, 1992). The statement of forest principles recognizes the "...vital role of all types of forests in maintaining the ecological processes and balance at the local, national, regional and global levels..." and that all types of forests "...embody complex and unique ecological processes which are the basis of their present and potential capacity to provide resources to satisfy human needs as well as environmental values...", points out that "Forestry issues should be examined in a holistic and balanced manner within the overall context of environment and development, taking into consideration the multiple functions and uses of forests..." and calls for a promotion of methodologies that provide a comprehensive assessment of economic and non-economic values of forest goods and services

18 The Rio conference has launched a number of regional initiatives to refine the forest principles and establish criteria and indicators for sustainable management of forests at regional, national and operational levels. In Europe, the 2 nd Ministerial Conference on the Protection of Forest, which took place in Helsinki one year after the Rio conference, defined sustainable management of forests as "the stewardship and use of forests and forest lands in such a way, and at a rate, that maintains their biodiversity, productivity, regeneration capacity, vitality and their potential to fulfill, now and in the future, relevant ecological, economic and social functions, at local, national, and global levels, and that does not cause damage to other ecosystems" (Second Ministerial Conference on the Protection of Forests in Europe, 1993). The same conference provided only general guidelines for the sustainable forest management of forests in Europe, for the conservation of biological diversity, for forestry cooperation with countries with economies in transition and for a process of long-term adaptation of forests to climate change. In the above definition a change in the way of viewing the forests is obvious. The view of the forest as a resource with multiple uses, which should be organized to serve the needs of the people is replaced with a more broad and ecological view of a natural system which evolves and needs stewardship. Instead of focusing on the output from the forest the focus is now on the forest ecosystem itself (KENNEDY ET AL., 1998). Both stewardship and use aim at maintaining the whole spectrum of forest functions, which should be provided now and in the future. A second outcome of this definition is the recognition that forest ecosystems function at multiple spatial scales, which form a hierarchy from local to global. Forest ecosystems are not close but rather dynamic systems, which interact with neighboring ecosystems exchanging materials and energy in evolving in time and space processes (FORMAN AND GORDON, 1986; DAFIS, 1986; KIMMINS, 1997). This implies a consideration of the forest ecosystems in a broader context of interacting ecosystems, where the interactions at one level have combined effects on the next level of the hierarchy. The next Ministerial Conference on the Protection of Forests (3 rd MCPFE) established Pan- European criteria and indicators for sustainable forest management (3 rd MCPFE, 1998a), which constitute a basis for development of national indicators and for international reporting, and Pan-European operational level guidelines for sustainable forest management (3 rd MCPFE, 1998b), which form a framework of recommendations for practical use in forest management. The six criteria at the national level are further divided into measured or descriptive indicators and the same criteria, at the operational level, are broken down into guidelines for forest management planing and for forest management practices. The operational level criteria and guidelines are presented in more detail here, as they have direct impact on forest management planning and consequently on management inventories. From the guidelines listed under each criterion in the resolutions of the - 8 -

19 conference, only the ones considered to have implications on management inventories are discussed here: Criterion 1: Maintenance and appropriate enhancement of forest resources and their contribution to global carbon cycles. The dynamic character of forest ecosystems and their interrelations at multiple spatial and temporal scales which can have global influences is recognized in this criterion. The same forest area has economic, ecological, cultural and social values and forest management should aim to maintain these values at economically, ecologically and socially desirable levels. Forest inventory should provide the necessary data for quantification of these values and for the determination of the desirable levels at which they can be sustained. Mapping of these values at appropriate spatial scales and a monitoring plan to detect changes of the values at temporal scales is also necessary. Criterion 2: Maintenance of forest ecosystem health and vitality. Key biotic and abiotic factors which can potentially affect ecosystem health and vitality should be identified by the inventory and ways to minimize the risk of degradation and damages to forest ecosystems should be provided. Monitoring is also essential as a tool to prevent degradation and damages. Criterion 3: Maintenance and encouragement of productive functions of forests (wood and non-wood). In this criterion, the well known principle of sustained yield is expanded to cover all the wood and non-wood products and moreover the merchantable and non-merchantable services of the forest ecosystems, and this should be done under economic efficiency. Concerning the wood products, a variety of inventory and assessment techniques which guarantee sustained yield have long ago been developed and applied (forming a tradition today) in Europe. Non-wood forest products and services need to be identified, and appropriate inventory techniques to be developed. Since most of these products and services can be physically measured, similar to the wood inventory techniques can be employed and respective models to determine the production potential can be developed. Criterion 4: Maintenance, conservation and appropriate enhancement of biological diversity in forest ecosystems. Since biodiversity covers a very wide spectrum of the variability in the biosphere at various levels, from genetic to species, ecosystems and landscapes - 9 -

20 and can be considered at various spatial scales special inventories are needed to capture specific aspects of biodiversity. Nevertheless, management inventories can have a substantial contribution in recording species diversity within stands (mainly of trees and shrubs), structural diversity of stands (horizontal and vertical) and landscape diversity (variability of land cover types within a landscape). Moreover, some habitats of special importance, endangered species, and special biotopes can efficiently be incorporated into management inventories. Criterion 5: Maintenance and appropriate enhancement of protective functions in forest management (notably soil and water). Special attention is to be paid to the protection functions of the forests, namely the protection of infrastructure, protection against erosion and protection of water resources. Forest management plans should take full account of these functions and forest areas fulfilling such functions should be registered and mapped. Criterion 6: Maintenance of other socioeconomic functions and conditions. Recreation resumes the first attention under socioeconomic functions, followed by provision of employment, public awareness, public participation in decision making and cultural values. Employment of appropriate inventory techniques to assess recreation and identify sites with special historical, cultural and spiritual significance is implied. The information needs as they come out from each criterion of sustainable management are very wide and difficult to be covered from a single inventory. Of course it is impossible to observe, register and evaluate all the relevant information for all the forest functions, but since a lot of information is common for different functions, an effort to systematize the information and standardize variables and inventory procedures could enable a better apprehension of the forest functions and contribute to the efficiency of management inventories. Clear is the fact that under the policy of sustainable management of forests the concept of sustainability is expanded to cover the whole values of forest ecosystems, and that is more than sustaining the yields of forest resources. Ecosystem sustainability is to be achieved by maintaining health and vital forest ecosystems which develop and function under minimum risks of damages and degradation and provide their multiple functions now and in the future. Forest inventory should follow an ecosystem approach and provide information on the components that comprise ecosystems and their relationships that allow ecosystems to function and evolve. Appropriate tools and methods to inventory ecosystem components