In the early 1980s, forest decline became a matter of public and scientific concern when forest stands with Norway spruce (Picea abies [L. ] Karst. ) showed evident damage on a large geographical scale throughout Europe. The causes of the observed symptoms could not be elucidated on the basis of the state of knowledge at that time. Therefore, several research projects were launched both in Germany and in some other countries in order to identify the relevant pathogenic factors. In 1985, the Federal Ministry for Research and Technology decided to include the site "Postturm", forest district Farchau/Ratzeburg, in the spon sorship of the research on forest decline as a site typical for lowlands and a sphere of anthropogenic urban influence. The investigation area is situated about 40 krn east-northeast of the city of Hamburg. Since spruce trees in particular showed severe decline, emphasis was laid on this species. The programme started in 1986 and extended to 1992, with some activities con tinuing beyond this time. Working groups from 13 institutions took part in the overall project.

This book is an outcome of a research project on "Sustainable Forestry and the Environment in Developing Countries". The project has been run by Metsantutki muslaitos METLA -the Finnish Forest Research Institute since 1987 and will be completed this year. A major output by this project has so far been a report in three volumes on "Deforestation or development in the Third World?" The purpose of our multidisciplinary research project is to generate new knowl edge about the causes of deforestation, its scenarios and consequences. More knowledge is needed for more effective, efficient and equitable public policy, both at the national and intemationallevels in supporting sustainable forestry in develop ing countries. Our project has specifically focused on 90 tropical countries as one group and on three subgroups by continents, as well as the three case study countries, the Philippines, Ethiopia and Chile. The University of Joensuu has been our active partner in the Philippine study. We have complemented the three cases by the analyzes of Brazil and Indonesia, the two largest tropical forest-owning countries. Some other interesting country studies were annexed to complement our book both by geography and expertise. The United Nations University, World Institute for Development Economics Research, UNUIWIDER in Helsinki Finland has also been partly engaged. Most of the results from its project on "The Forest in the South and North in Context of Global Warming" will, however, be published later in a separate book.

The chapters in this book represent detailed versions of papers presented at the Symposium on Viral Genes and Plant Pathogenesis held at Lexington, Kentucky on October 16 and 17, 1989. In selecting topics and authors, we attempted to have represented a spectrum of systems which are at the forefront of research on plant virus genes and gene products, particularly as they relate to plant disease. The book also contains pertinent discussion of the papers presented at the symposium, as well as summaries, observations and projections of future research directions prepared by the session chairmen. We wish to express our appreciation to Dr. D. L. Davis, of the RI. Reynolds Tobacco Company for suggesting the organization of the Symposium and the publication of the proceedings, and to the R 1. Reynolds Tobacco Company for the financial support which made the symposium possible. We also wish to thank those of our colleagues in the Department of Plant Pathology, University of Kentucky, who very ably and in many ways contributed to the organization and conduct of the conference. Thomas P. Pirone lohnG. Shaw v Contents Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi INDUCTION OF HOST GENES BY THE HYPERSENSITIVE RESPONSE OF TOBACCO TO VIRUS INFECTION J. F. Bol, C. M. A. van Rossum, Bl. C. Cornelissen and H. J. M. Linthorst . . . . . . . . . . . . . . . . . l COAT PROTEIN MEDIATED RESISTANCE IN TRANSGENIC PLANTS Roger N. Beachy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 STRUCTURE AND FUNCTIONS OF TOBACCO MOSAIC VIRUS RNA Yoshimi Okada, Tetsuo Meshi, and Yuichiro Watanabe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

We have the pleasure to present to you the proceedings of the XIVth congress of the "Association pour l'Etude Taxonomique de la Flore d'Afrique Tropicale" (AETFAT). The XIVth AETFAT congress was held from 22 to 27 August 1994, at the Wageningen International Conference Centre in Wageningen, The Netherlands. The congress was attended by 215 participants, 104 of which came from 28 African countries. During the congress 46 papers and more than 100 posters were presented, the texts of most of which are presented in these Proceedings. The expenses of the congress were covered by grants from the Wageningen Agri- cultural University, the Royal Netherlands Academy of Sciences, and others; see page XVI for a complete list. Funds for the participation of 55 members from Africa came from a number of sponsors, in particular from the Directorate General for International Cooperation, the Technical Centre for Agricultural and Rural Co-operation, the Tropenbos Foundation, and Shell Nederland. We express our sincerest thanks to all contributors. The convenors who organized the symposia, and edited the papers afterwards, are gratefully acknowledged. The editors also acknowledge the valuable help of J.J. Bos and A.J.M. Leeuwenberg, both with preparations in the Organizing Committee, as well as with ftnal editing. The printing was undertaken by Kluwer Academic Publish- ers, in collaboration with A.C. Plaizier.

In recent years many of the conventional methods of insect control by broad spectrum synthetic chemicals have come under scrutiny because of their unde sirable effects on human health and the environment. In addition, some classes of pesticide chemistry, which generated resistance problems and severely affected the environment, are no longer used. It is against this background that the authors of this book present up-to-date findings-relating to biochemical sites that can serve as targets for developing insecticides with selective prop erties, and as the basis for the elucidation of resistance mechanisms and countermeasures. The book consists of eight chapters relating to biochemical targets for insec ticide action and seven chapters relating to biochemical modes of resistance and countermeasures. The authors of the chapters are world leaders in pesti cide chemistry, biochemical modes of action and mechanisms of resistance. Biochemical sites such as chitin formation, juvenile hormone and ecdysone receptors, acetylcholine and GABA receptors, ion channels, and neuropeptides are potential targets for insecticide action. The progress made in recent years in molecular biology (presented in depth in this volume) has led to the iden tification of genes that confer mechanisms of resistance, such as increased detoxification, decreased penetration and insensitive target sites. A combina tion of factors can lead to potentiation of the resistance level. Classifications of these mechanisms are termed gene amplification, changes in structural genes, and modification of gene expression.

The emergence of landscape ecology during the 1980s represents an impor tant maturation of ecological theory. Once enamored with the conceptual beauty of well-balanced, homogeneous ecosystems, ecologists now assert that much of the essence of ecological systems lies in their lumpiness. Patches with differing properties and behaviors lie strewn across the land scape, products of the complex interactions of climate, disturbance, and biotic processes. It is the collective behavior of this patchwork of eco systems that drives pattern and process of the landscape. is not an end point This realization of the importance of patch dynamics in itself, however. Rather, it is a passage to a new conceptual framework, the internal workings of which remain obscure. The next tier of questions includes: What are the fundamental pieces that compose a landscape? How are these pieces bounded? To what extent do these boundaries influence communication and interaction among patches of the landscape? Will con sideration of the interactions among landscape elements help us to under stand the workings of landscapes? At the core of these questions lies the notion of the ecotone, a term with a lineage that even predates ecosystem. Late in the nineteenth century, F. E. Clements realized that the transition zones between plant communi ties had properties distinct from either of the adjacent communities. Not until the emergence of patch dynamics theory, however, has central signif icance of the ecotone concept become apparent."

Forest resources are an ideal starting point for economic analysis of sustainability. In this book, leading economists discuss key aspects of sustainability and sustainable forest management including complexity, ethical issues, consumer choice theory, intergenerational equity, non-convexities, and multiple equilibria. This systematic critique of neoclassical economic approaches is followed by a companion work, Institutions, Sustainability, and Natural Resources: Institutions for Sustainable Forest Management, Volume 2 in the series.

This volume brings together papers from geotechnical and civil engineers, biologists, ecologists and foresters. They discuss current problems in slope stability research and how to address them using ground bio- and eco-engineering techniques. Coverage presents studies by scientists and practitioners on slope instability, erosion, soil hydrology, mountain ecology, land use and restoration and how to mitigate these problems using vegetation.

Cereal uses range from human food and beverages to animal feeds and industrial products. It is human food and beverages which are the predominant uses covered in this book, since the nutritional quality of cereals for animal feed is described in other publications on animal nutrition, and industrial products are a relatively minor use of cereals. Cereals are the main components of human diets and are crucial to human survival. Three species, wheat, rice and maize, account for the bulk of human food. Barley is the major raw material for beer production and ranks fourth in world production. Other species such as sorghum are regionally important. This book covers all the major cereal species: wheat, rice, maize, barley, sorghum, millet, oats, rye and triticale. Specific chapters have been devoted to a description of the major end-uses of each of the species and to definition of the qualities required for each of their end uses. The functional and nutritional quality of cereals determines their suitability for specific purposes and may limit the quality of the end product, influencing greatly the commercial value of grain. An under standing of the factors that determine grain quality is thus important in the maintenance of efficient and sustainable agricultural and food production. The biochemical constituents of the grain that determine quality have been described in chapters on proteins, carbohydrates and other components. An understanding of the relationships between grain composition and quality is important in selecting grain for specific uses."

Mycorrhizal fungi are microbial engines which improve plant vigor and soil quality. They play a crucial role in plant nutrient uptake, water relations, ecosystem establishment, plant diversity, and the productivity of plants. Scientific research involves multidisciplinary approaches to understand the adaptation of mycorrhizae to the rhizosphere, mechanism of root colonization, effect on plant physiology and growth, biofertilization, plant resistance and biocontrol of plant pathogens. This book discusses and goes into detail on a number of topics: the molecular basis of nutrient exchange between arbuscular mycorrhizal (AM) fungi and host plants; the role of AM fungi in disease protection, alleviation of soil stresses and increasing grain production; interactions of AM fungi and beneficial saprophytic mycoflora in terms of plant growth promotion; the role of AM fungi in the restoration of native ecosystems; indirect contributions of AM fungi and soil aggregation to plant growth and mycorrhizosphere effect of multitrophic interaction; the mechanisms by which mycorrhizas change a disturbed ecosystem into productive land; the importance of reinstallation of mycorrhizal systems in the rhizosphere is emphasized and their impact on landscape regeneration, and in bioremediation of contaminated soils; Ectomycorrhizae (ECM) and their importance in forest ecosystems and associations of ECM in tropical rain forests function to maintain tropical monodominance; in vitro mycorrhization of micro-propagated plants, and visualizing and quantifying endorhizal fungi; the use of mycorrhizae, mainly AM and ECM, for sustainable agriculture and forestry.

This second edition has been completely revised and has incorporated significant changes that have occurred in wood anatomy over the past years. "This book is recommended to all who are interested in a modern, stimulating, competent, and well illustrated work." (Holzforschung).

This volume summarizes the current knowledge on the exchange of trace gases between forests and the atmosphere with the restriction that exclusively carbon and nitrogen compounds are included. For this purpose the volume brings together and interconnects knowledge from different disciplines of biological and atmospheric sciences. It covers microbial and plant processes involved in the production and consumption of these trace gases; the exchange processes between forest soils and vegetation on the one hand, and the atmosphere on the other hand; the fate of the trace gases exchanged inside the atmosphere as well as environmental influences on the exchange of trace gases between forest ecosystems and the atmosphere. With this interdisciplinary approach the volume provides the background for an evaluation of the exchange of trace gases between forest ecosystems and the atmosphere and man-made disturbances of this exchange.

Natural resource governance is central to the outcomes of biodiversity conservation efforts and to patterns of economic development, particularly in resource-dependent rural communities. The institutional arrangements that define natural resource governance are outcomes of political processes, whereby numerous groups with often-divergent interests negotiate for access to and control over resources. These political processes determine the outcomes of resource governance reform efforts, such as widespread attempts to decentralize or devolve greater tenure over land and resources to local communities. This volume examines the political dynamics of natural resource governance processes through a range of comparative case studies across east and southern Africa. These cases include both local and national settings, and examine issues such as land rights, tourism development, wildlife conservation, participatory forest management, and the impacts of climate change, and are drawn from both academics and field practitioners working across the region. Published with IUCN, The Bradley Fund for the Environment, SASUSG and Norwegian Ministry of Foreign Affairs

Roelof A. A. Oldeman Tropical hardwoods are one of the essential cogs in the complex socio-economic machinery keeping alive an ever-increasing humanity with steadily rising claims upon a finite-resource environment. Their position in this context at first sight seems to be analogous to that of other commodities, such as rubber, metals, mineral oil, tropical fruits and many more. Looking closer, however, tropical hardwoods occupy a special place. Their vast majority, unlike tropical crops, still comes forth from natural forests being exploited by man. This exploitation straight from the natural resource is something they have in common with oil and metals, but the fact that they grow in living systems places them closer to crops. Natural forest ecosystems are not renewable. Timber producing trees, however, can be made into a renewable resource on condition that ways and means are found to cultivate them as a crop. be understood as a socio-economic The tropical hardwood situation can best chain, with the resource base at one end, the consumer community at the other and everything that has to do with the market in the middle. Now, at the resource side, the economics of tropical hardwood extraction barely got out of the primeval ways of wood-gathering by hand and by axe, which were still predominant in the nineteen-forties. There, the offer of natural products was so immense and so near to hand that no care had to be taken of the resource.

There is a strong movement towards uneven-aged forest management based on the idea that such stands increase or at least maintain soil fertility, increase biodiversity, and improve stand resilience. This shift in forest management practice renders existing yield tables increasingly unreliable. Among potential alternatives are tree growth models, because they predict the growth of each tree within a forest stand. This book summarizes three years of work related to the topic, carried out as a joint effort of leading tree growth modellers across Europe together with forest companies. By means of nine specific examples it demonstrates the problem-solving potential of tree growth modeling theory as required by various end-user groups.

Dendrochronologists have long estimated the impact of climate on tree-ring growth by empirical-statistical methods. The use of the model is illustrated with examples from widely differing environments, and possible future directions for model development and application are discussed. As forests are the main carbon sink on land, the results are of great importance for all global change studies.

This book consists of papers presented at a symposium "PLANT-INDUCED SOIL CHANGES: PROCESSES AND FEEDBACKS" that was held during the American Society of Agronomy-Soil Science Society of America Annual Meeting in Indianapolis, November 4-8, 1996. The papers were also pub of Biogeochemistry (Vol. 42, nos. 1 and 2, 1998). The lished in a special issue symposium was built on the growing realisation that plant-induced changes in soil feed back in various ways to natural vegetations, giving rise to a plethora of plant-soil interactions beyond the classical one-way cause-and-effect pathways plant-to-soil and soil-to-plant. The aim of this special issue is not in the first place to present new research findings, but to review and discuss the more holistic aspects of plant-soil interactions, providing more room for speculation than do most collections of research papers. After a general introduction which emphasises ecological and evolutionary aspects of plant-soil interac ions (van Breemen and Finzi), three papers deal with particular effects of plants on soil properties: mineralogy (Kelly et al. ), soil structure (Angers and Caron) and soil fertility (Berendse). Next, five papers take up plant-soil interactions in specific biomes: forests (Binkley and Giardina; Gobran et al. ), grasslands (Burke et al.; Epstein et al. ) and deserts (Schlesinger and Pilmanis). Two papers discuss plant-soil interactions via effects of differences in litter quality in specific ecosystems: California's pygmy forest (Northup et al. ) and the Alaskan Taiga (Schimel et al. )."

Mycorrhiza - the symbiosis between plants and fungi - plays a key role in plant life. This book reviews for the first time the current knowledge of 15 individual genera of ectomycorrhizal fungi. It is unique in that each chapter is dedicated to a single fungal genus, each written by internationally recognized experts on the respective fungal genera. It is thus an invaluable reference source for researchers, students and practitioners in the fields of mycorrhizal biology, mycology, forestry, plant sciences and soil biology.

On the occasion of the 50th Anniversary of the International Association of Wood Anatomists several symposia were held during the 13th International Botanical Congress in Sydney, August 1981. Extended versions of most of the invited papers presented there, and some additional papers on aspects which could not be included in the congress program constitute the contents of this book, which intentionally received the pretentious title 'New Perspectives in Wood Anatomy'. To some readers it may seem a paradox that under this heading papers on a diversity of partly traditional wood anatomical subjects are assembled, even including two with a historical emphasis. However, a study of the history of wood anatomy and of how students of that discipline joined forces in an inter national association, brings to light many facts and views which deserve the attention of present day and future wood scientists as a potential source of in spiration for their research and organisational work."

This book is a collection of papers presented at the international symposium on forest sector analysis held in Miyazaki, Japan, in 1998. It is structured with three themes: understanding global forest sector issues, discussing the contribution of modeling efforts to forest sector analysis, and discussing the role of Japanese forest policy in a global sense. The most important features are the case studies using various types of forest sector models. From a modeling perspective, changes in modeling efforts include more detail of spatial and multiple market levels, intergenerational welfare concerns, non-market valuation issues, and explicit treatment of the uncertainty inherent in both the policy process and in the biophysical systems. The reader of this book will benefit not only from presentation of forest utilization issues in different nations, but also from the interrelatedness of the theory and application of forest sector modeling.

Freer Trade, Sustainability, and the Primary Production Sector in the Southern European Union is the first full-scale academic work to cap ture the primary production sector policy aspects of trade liberaliza tion and sustainability with a detailed focus on a typical southern EU country, Greece. Many efforts were pooled together in making this book. In May 1996 the Department of Economics of the University of Crete organ ized an international conference on European Agriculture in the light of the recent WTO agreement and the need for sustainable develop ment. The conference was sponsored by the European Commission (DG XII, contract no ENV4-CT-96-6514), the Economic and Social Research Council (ESRC, contract no L320263049), the Hellenic Ministries for Agriculture and for the Environment, and the University of Crete. While summarizing the conclusions of the conference, sev eral speakers felt that the issues relating to the Southern EU would de serve separate coverage. The conference directors judged that cover age of the issues for a single Southern EU country might have an ad vantage, regarding detail, over a cross country analysis which would certainly be welcome at a later stage. Responding to this call, the University of Crete generously reallo cated all of its infra-structural costs covered by DG XII, ESRC, and the other sponsors above, in the form of a new grant to host a follow-up conference aiming to explore the issues for Greece."

During the 4th International Consultation on Forest Genetics and Tree Building, held in 1998 in Beijing, China, leading scientists were invited to review past achievements, to redefine the role of forest genetics and breeding in contemporary forestry, and to set priorities for future research and development. On the basis of the invited presentations, the volume summarizes the state of knowledge in various fields, such as the impact of forest management and of changing environmental conditions on genetic resources, and the value of genetic markers as indicators for adaptational potential, as well as the tasks of conservation. Detailed reports from the different continents provide a comprehensive diagnosis of the global situation of forest genetics and tree breeding research. The book offers not only an overview of contemporary trends and expected future developments, but also identifies current main problems in funding and cooperation. It may prove therefore useful not only for scientists, university lecturers and advanced students in the field of forestry, ecology and conservation biology, but also for decision makers and managers in companies and conservation organizations.

This handbook was designed as a reference tool for forest geneticists, tree breeders and other tree improvement personnel, as well as a textbook for university courses and short-courses at the graduate level in quantitative genetics. The chapters focus on the decision points faced by quantitative geneticists and breeders in designing programs and analyzing data. Beginning with a justification for the use of quantitative genetics in decision making in tree improvement programs, the book continues with a brief presentation of fundamental principles, followed by discussions and evaluations of mating designs and field test designs, the use of best linear predictors to estimate breeding values, the use of computer programs in the analysis of variance for genetic information, the deployment of genetically improved stock for capturing gains, the use of economic models for program justification, and the development of seed transfer guidelines.

Long-range models that include product and resource detail are essential to meaningful analysis of both industry and resource sustainability. Taking this as its central argument, this book provides essential reading to anyone interested in projecting the future of either the forest products market and/or the forest resource conditions. It is aimed at policy makers, model builders, researchers and graduate students who are building or using forest sector models, as well as at forest industry managers and analysts.

While focusing on a specific modeling system the US Timber Assessment models the authors highlight the general elements that might comprise a forest-sector market model of any country or region. Approaches to policy analysis are also general and equally applicable to both national and multi-national forest policy development outside the US particularly in relation to on-going efforts to formulate national programs of sustainable forestry.

The text provides literature surveys on relevant modeling issues and policy concerns, and demonstrates the application of the modeling system using a base case 50 year projection and a small set of scenarios to illustrate, for example, the effects of changes in public harvest policies, global change, variations in investments in silviculture, and globalization.

Darius Adams and Richard Haynes are widely recognized as leading experts in the forest sector modeling field."

Forest Analytics with R combines practical, down-to-earth forestry data analysis and solutions to real forest management challenges with state-of-the-art statistical and data-handling functionality. The authors adopt a problem-driven approach, in which statistical and mathematical tools are introduced in the context of the forestry problem that they can help to resolve. All the tools are introduced in the context of real forestry datasets, which provide compelling examples of practical applications. The modeling challenges covered within the book include imputation and interpolation for spatial data, fitting probability density functions to tree measurement data using maximum likelihood, fitting allometric functions using both linear and non-linear least-squares regression, and fitting growth models using both linear and non-linear mixed-effects modeling. The coverage also includes deploying and using forest growth models written in compiled languages, analysis of natural resources and forestry inventory data, and forest estate planning and optimization using linear programming. The book would be ideal for a one-semester class in forest biometrics or applied statistics for natural resources management. The text assumes no programming background, some introductory statistics, and very basic applied mathematics.