In the early seventies, scientists in Israel and The Netherlands started a cooperative project on actual and potential production under semi-arid conditions. In Israel research concentrated on primary production of natural pastures and small grain crops, and on the associated secondary production of small ruminants. Most of the experimental work was carried out at the Migda Experimental Farm in the semi-desert of the northern Negev where the long term average annual rainfall is 250 mm. In The Netherlands existing facilities in Wageningen were used for measuring growth, photosynthesis and transpiration of Negev pasture plants and small grains under controlled conditions, both as individual plants and as simulated swards and crops. The joint research program was initiated by the late N.H. Tadmor and A. Dovrat from Israel and by C.T. de Wit and Th. Alberda from The Netherlands and conducted by various scientists from both countries, some of whom are among the authors of this book. The experimental results first served as a basis for the development, calibration and validation of simulation models of the growth and water use of pasture and crops. Subsequently, additional models were developed, allowing incorporation of socio-economic considerations, both at the farm and regional level, so harnessing the research results for analysis of regional development possibilities."

This volume of the series The Plant Viruses is devoted to viruses with rod-shaped particles belonging to the following four groups: the toba moviruses (named after tobacco mosaic virus), the tobraviruses (after to bacco rattle), the hordeiviruses (after the latin hordeum in honor of the type member barley stripe mosaic virus), and the not yet officially rec ognized furoviruses (fungus-transmitted rod-shaped viruses, Shirako and Brakke, 1984). At present these clusters of plant viruses are called groups instead of genera or families as is customary in other areas of virology. This pe culiarity of plant viral taxonomy (Matthews, 1982) is due to the fact that the current Plant Virus Subcommittee of the International Committee of Taxonomy of Viruses is deeply split on what to call the categories or ranks used in virus classification. Some plant virologists believe that the species concept cannot be applied to viruses because this concept, according to them, necessarily involves sexual reproduction and genetic isolation (Milne, 1984; Murant, 1985). This belief no doubt stems from the fact that these authors restrict the use of the term species to biological species. According to them, a collection of similar viral isolates and strains does constitute an individ ual virus, i. e., it is a taxonomy entity separate from other individual viruses."

Central Amazonian floodplain forests are an unique and endangered ecosystem. The forests grow in areas that are annually flooded by large rivers during mean periods of up to 8 months and at depths of up to 10 m. Despite this severe stress, these forests consist of over 1,000 species and are by far the most species-rich floodplain forests worldwide. The trees show a broad range of morphological, anatomical, physiological, and phenological adaptations that enable them not only to survive the adverse environmental conditions, but also to produce large amounts of biomass when the nutrient levels in water and soils are sufficiently high. This is the case in the floodplains of white-water rivers, which are used for fisheries, agriculture, and cattle-ranching but which also have a high potential for the production of timber and non-timber products, when adequately managed. Latest research on ecophysiology gives insight how tree species adapt to the oscillating flood-pulse focusing on their photosynthesis, respiration, sap flow, biochemistry, phenology, wood and leave anatomy, root morphology and functioning, fruit chemistry, seed germination, seedling establishment, nitrogen fixation and genetic variability. Based on tree ages, lifetime growth rates and net primary production, new concepts are developed to improve the sustainability of traditional forest managements in the background of an integrated natural resource management. This is the first integrative book on the functioning and ecologically oriented use of floodplain forests in the tropics and sub-tropics.It provides fundamental knowledge for scientist, students, foresters and other professionals on their distribution, evolution and phytogeography. "This book is an excellent testimony to the interdisciplinary collaboration of a group of very dedicated scientists to unravel the functioning of the Amazonian Floodplain forests. They have brought together a highly valuable contribution on the distribution, ecology, primary production, ecophysiology, typology, biodiversity, and human use of these forests offering recommendations for sustainable management and future projects in science and development of these unique wetland ecosystems. It lays a solid scientific foundation for wetland ecologists, foresters, environmentalists, wetland managers, and all those interested in sustainable management in the tropics and subtropics." Brij Gopal, Executive Vice President International Society for Limnology (SIL).

Changes in production, demand, supply, and trade patterns; the impact of green building and bioenergy on industry practices and policy infrastructure; and new economies with production advantages and large consumption bases all present challenges and opportunities in the forest sector. With contributions from leading experts in academia and professional organizations, The Global Forest Sector: Changes, Practices, and Prospects fills a gap in the literature that is preventing students, scholars, and policy makers from developing a timely, structured, big-picture view of forest sector business. In addition, the book reviews current thinking on a wide variety of business management issues in the forest sector.

The book covers managing change in the global forest sector and the impact of globalization on forest users. It discusses markets and market forces, new products and product categories, and the influence of China and Russia. The book then examines the environmental paradigm, including environmental activism, sustainability, and the impact of green building and bioenergy. The book concludes with coverage of the role of information technology, corporate social responsibility, innovation, and next steps.

Overall, this book helps readers both develop a bird s eye view of the changes surrounding the forest sector as well as have a magnified view of numerous managerial issues associated with these changes. The content paints a picture of the current and changing forest sector including the state of forests, the nature of markets, the newly emerged patterns of stakeholder impact, and evolution of key business practices. It provides the foundation needed to develop the conservation-based economy required for future success in the global forest sector."

With one volume each year, this series keeps scientists and advanced students informed of the latest developments and results in all areas of the plant sciences.
The present volume includes reviews on genetics, cell biology, physiology, comparative morphology, ecology and vegetation science.

Reproductive Biology of Plants is a comparative account of reproduction in viruses, bacteria, cyanobacteria, algae, fungi, lichens, bryophytes, pteridophytes, gymnosperms and angiosperms, each chapter written by an expert in the field. Special emphasis is placed on the truly comparative approach illustrating the vast range from simplicity to complexity in structure and function with respect to the various organisms.

The International Society on OXygen Transport to Tissue (ISO'IT) has canpleted nine years as a society since its first fonnal meeting at Charleston-Clanson, South Carolina, United States of America in 1973. Prior to this time an active group of scientists and engineers rret in w:: >rkshop environrrents, on a periodic basis, around the w:: >rld. Meetings are ncM on an annual basis, alternating between Europe and the United States. The international gatherings include scientists and engineers in a variety of fields. ISOIT has produced a stable forum for the exchange of info: rmation on the rnicroenvirornnent of living cells, ranging fran the utilization of mathematics and engineering, through physiology and radiobiology, to clinical applications. The proceedings of these meetings have been codified into six books, four of them published by Plenum Press in its prestigious Advances in Experimental Medicine and Biology series. This volume, together with the next two volumes that will follCJV.l the meetings in Dortmund, Gennany in 1982 and in Ruston, Louisiana in 1983 will provide further chapters in the history of this fascinating field of knCJV.lledge. OUr thanks are given to all the participants and contributors to the Detroit meeting. We hope that the strength of the society will grow in caning years, and that our contribution will eventually be felt in: inproving the treatment of the sick, and in enhancing the thought processes of the intellectual.

Within the extreme diversity of aquatic and terrestrial plant genera, each has characteristic cell wall forms. A number of hypotheses have been advanced to explain differences in microfibril arrangements across anyone such wall. Of those, only the 'multinet' theory, which involves the postulation of reorientation of microfibrils caused by cell extension, now has a substantial number of ad herents. However, many scientists are sceptical of its validity; obviously it is incompatible with various observed microfibril arrangements. The tenet of this study is that any such hypothesis can be valid only if it is applicable to all plant forms and wall types. Initially, reanalyses are made of data claimed to confirm justification for multi net postulations. The results show that previous deductions from those data, in support of multinet, are subject to serious challenge. Similarly, a re-examination of the observations, which inspired the multinet theory, shows they have a more logical explanation. Herein, it is concluded that cell wall development involves biophysical factors, which neces sarily prevent multinet's postulated large reorientations of microfibrils, after their formation. Unfortunately the previously most recent published theory, which is based on the absence of reorientation during extension, fails to answer the fundamental question of how alternating orientations between lamellae are controlled, or explain variations in thickness of wall layers. Extensive published data are used to identify forces involved in cell wall development.

Dutch elm disease is a significant problem in forestry and horticulture which has proven remarkably difficult to ameliorate. Since the introduction of the Dutch elm disease pathogen to North America, the disease has devastated the elm population of this continent and has been the subject of intensive research. This book summarizes the range of approaches that have been taken to address the disease, and emphasizes the significant progress over the past decade in applying methods from cell and molecular biology. Dutch Elm Disease: Cellular and Molecular Approaches will be of interest to scientists in plant pathology, horticulture, forestry, biological control, and plant breeding.

This is the third annual compendium of a Technical Session of the Physiology Working Group of the Society of American Foresters held at the National Convention. Specialists in a dedicated area of tree physiology were invited to prepare chapter contributions synthesizing the status of knowledge in their area of expertise. Plant growth regulators (PGRs) was selected as the topic for in-depth examination at the 1986 Technical Session because a knowledge of how these "secondary messengers" regulate tree morphogenesis is vital to applications of biocontrol and biotechnology. Plant growth regulators have been the subject of numerous reviews in recent years. However, few have dealt specifically with woody perennials, and they are generally confined to single processes and/or organs. This volume attempts to provide a more comprehensive treatise of PGRs as they influence various ontogenetic events in forest trees. Reproductive physiology, both sexual and asexual, is emphasized because of its relevance to current efforts directed at increasing efficiency in the breeding and production of genetically improved trees for reforestation. The chapters on vegetative growth will be of interest to silviculturists and urban foresters as they consider cultural treatments in the management of forests and individual trees for specific products and purposes. This book should serve as a valuable text and source of reference for students, researchers and other professionals interested in gaining a better understanding of PGRs. The reader, however, who expects definitive answers to how PGRs function or can be used to control specific processes is likely to be disappointed.

Chemistry of Plant Protection, Volume 7, provides critical review articles on new aspects of herbicide resis- tance, serving the needs of research scientists, pesticide manufacturers, government regulators, agricultural practitioners.

Forest land managers face the challenges of preparing their forests for the impacts of climate change. However, climate change adds a new dimension to the task of developing and testing science-based management options to deal with the effects of stressors on forest ecosystems in the southern United States. The large spatial scale and complex interactions make traditional experimental approaches difficult. Yet, the current progression of climate change science offers new insights from recent syntheses, models, and experiments, providing enough information to start planning now for a future that will likely include an increase in disturbances and rapid changes in forest conditions. Climate Change Adaptation and Mitigation Management Options: A Guide for Natural Resource Managers in Southern Forest Ecosystems provides a comprehensive analysis of forest management options to guide natural resource management in the face of future climate change. Topics include potential climate change impacts on wildfire, insects, diseases, and invasives, and how these in turn might affect the values of southern forests that include timber, fiber, and carbon; water quality and quantity; species and habitats; and recreation. The book also considers southern forest carbon sequestration, vulnerability to biological threats, and migration of native tree populations due to climate change. This book utilizes the most relevant science and brings together science experts and land managers from various disciplines and regions throughout the south to combine science, models, and on-the-ground experience to develop management options. Providing a link between current management actions and future management options that would anticipate a changing climate, the authors hope to ensure a broader range of options for managing southern forests and protecting their values in the future.

Since the middle of the Sixties, new types of formulation for biologically active com pounds have been developed, which have been introduced into the literature under the term Controlled Release Formulations (CRF). Stimulated by results from former and successful pharmaceutical research, which was engaged in the production of prepa rations with protracted effects (introduction onto the market in the year 1952 of D amphetamine in the form of pellets, coated to varying degrees with fats and waxes) 1), experiments were carried out to transfer the prolongation of effectiveness to pesticidal substances also, by means of a depot formulation. Initial work was concerned with the production of protective coatings for sonar systems in marine ecosystems. By means of antifouling paints or rubber coatings containing tri-n-butyl-tin oxide (TBTO), the growth of marine organisms on sonar domes, buoys and hulls in the water could be effectively prevented 2. 3). Controlled release formUlations of pesticides are defined as depot systems which continuously release their toxic constituents into the environment over a specified period of time (usually months to years) 4). According to this definition, such formu lations can be successfully employed where a chronic exposure to biologically active compounds is required over a longer period. The following hypothetical example is intended to illustrate this 5). In Fig. 1, the duration of activity of a non-persistent pesticide with a loss rate under environmental conditions of t1/2 = 15 days, is graphically illustrated."

This book integrates the latest global developments in forestry science and practice and their relevance for the sustainable management of tropical forests. The influence of social dimensions on the development of silvicultural concepts is another spotlight. Ecology and silvicultural options form all tropical continents, and forest formations from dry to moist forests and from lowland to mountain forests are covered. Review chapters which guide readers through this complex subject integrate numerous illustrative and quantitative case studies by experts from all over the world. On the basis of a cross-sectional evaluation of the case studies presented, the authors put forward possible silvicultural contributions towards sustainability in a changing world. The book is addressed to a broad readership from forestry and environmental disciplines.

After the publication of the Diagnostic Manual for the Identification of Insect Pathogens, the authors received many queries asking why they had not included the larger metazoan parasites as well as the microbial forms. An examination of the literature indicated that pictorial guides to the identification of nematodes and the immature stages of insect parasites were unavailable. Consequently we decided to rewrite the sections cover ing insect pathogens and combine these with new sections on ento mogenous nematodes and the immature stages of insect parasites. The result is the present laboratory guide, which is unique in covering all types of biotic agents which are found inside insects and cause them injury or disease. Included as parasites are insects and nematodes. Among the pathogens included are viruses, rickettsias, bacteria, fungi, and protozoans. Emphasis is placed on identification with an attempt to use the most easily recognizable characters. Use of a certain number of technical terms is unavoidable, and explanations of these can be found in most biological dictionaries or the glossary of invertebrate pathology prepared by Steinhaus and Martignoni (1970).

Traditionally, intercellular communication and the regulation of biological functions of the body have been considered the role of two major and distinct systems: the nervous system and the endocrine system. The classic nervous system transmitted its signal rapidly by using electrical currents, whereas the signals used by the endocrine system were hormones produced by endocrine glands which reached the target tissues via the blood stream. During the past few decades, it has become apparent that these systems of intercellular com munication are not distinct and the signal messenger molecules are not unique to one or the other system. Many classic endocrine hormones are found in and act on nervous tissues and evidence exists for their de novo synthesis by neural related tissues. An exciting development in this area is the possibility that insulin and insulin-like growth factors (IGF) are not only produced by neural tissues but also exert profound physiological and biochemical effects on these tissues. The area of investigation of CNS insulin and IGF has been expanding rapidly and the availability of this book complete with up-to-date reviews on the subject by leaders in the field allows other scientists to utilize the knowledge in planning and adapting the latest ideas for future experiments. In addition, the book provides a collection of up-to-date articles for teachers to be used for the latest instructional material. The first section of the book covers general aspects of insulin receptors and insulin action."

The 21st century has seen the beginnings of a great restoration effort towards the world's forests, accompanied by the emergence of an increasing literature on reforestation, regeneration and regrowth of forest cover. Yet to date, there is no volume which synthesises current knowledge on the extent, trends, patterns and drivers of reforestation. This edited volume draws together research from leading researchers to explore reforestation and forest regrowth across the world, from multiple dimensions - including ecosystem services, protected areas, social institutions, economic transitions, remediation of environmental problems, conservation and land abandonment - and at different scales. Detailing the methods and analyses used from across a wide range of disciplines, and incorporating research from North, South and Central America, Africa, Asia and Europe, this groundbreaking book provides a global overview of current trends, explores their underlying causes and proposes future forest trajectories. The first of its kind, the book will provide an invaluable reference for researchers and students involved in interdisciplinary research and working on issues relevant to the biophysical, geographic, socioeconomic and institutional processes associated with reforestation.

Forests comprise the greatest storage of carbon on land, provide fuel for millions, are the habitat for most terrestrial biodiversity, and are critical to the economies of many countries. Yet changes in the extent and dynamics of forests are inherently difficult to detect and quantify. Remote sensing technologies may facilitate the measurement of some key forest properties which, when combined with other information contained in various computer models, may allow for the quantification of critical forest functions. This book explores how remote sensing and computer modeling can be combined to estimate changes in the carbon storage, or productivity, of forests - from the level of the leaf to the level of the globe. Land managers, researchers, policy makers and students will all find stimulating discussions among an international set of experts at the cutting edge of the interface between science, technology and management.

There are clearly many directions in which the further development of the GUS gene fusion system can progress. Some of these have been outlined above, but others can be imagined. There are no reasons to limit our conceptions of the use of GUS gene fusions to analysis and manipulation of single genes. We can envision numerous marked genes - perhaps with several new fusion systems - giving valuable information about gene interaction, or population structure. The study of plan- pathogen and plant symbiont interactions can progress rapidly with simple quantitative markers for genes and individuals. We can imagine ways of using gene fusions to report on crop physiology or other complex phenotypes, thereby enhancing the accuracy and speed of screening. Introduction of the biosynthetic pathway for glucuronide detoxification by expressing genes for the UDP-glucuronyl transferases in plants may result in novel mechanisms for plants to deal with xenobiotics such as insecticides or herbicides. Synthesis of substrates, which until now has been performed chemicall- resulting in expensive compounds - can be done biosynthetically. This should make the system not only the most powerful gene fusion system for agriculture, but also the most accessible.

R. F. HUTTL AND W. SCHAAF Brandenburg Technical University Cottbus, Chair of Soil Protection and Recultivation, P.O. Box 10 13 44, 03013 Cottbus, Germany The health status of forest trees and stands is determined by numerous site factors such as chemical, physical, and biological soil factors, water supply, climate, weather conditions, management history as well as atmospheric deposition impacts. In this context, the nutrient supply is an important evaluation parameter. Forest trees well supplied with nutrients are more resistant to stresses that affect the forest ecosystem than other trees. This is true for both biotic and abiotic influences. Therefore the investigation of the so-called 'new type forest damage' was aimed at the exact determination of the health status of damaged trees. When considering the complete forest ecosystem, health (=vitality) means the sustainable ability to withstand negative environmental influences and still remain stable and productive. From this viewpoint, an optimal nutritional status is a prerequisite for an optimal health status. The term 'new type forest damage' comprises a number of damage symptoms which have been observed in various tree species on very different sites since the mid-1970s, particularly in Europe and North America. However, they occurred much more intensively in the 1980s. Generally, this forest damage was thought to be related to negative impacts of air pollutants.

Root hairs are tip-growing cells that originate from epidennal cells called trichoblasts. Their role may be simply thought of as extending the surface area of the root to facilitate absorption of nutrients and water. However, as you will see in this book, the root hair is far more than that. To an increasingly larger number of plant biologists, the root hair is a model cell. It grows in much the same way as a pollen tube, by sending vast numbers of vesicles containing cell wall precursors to a rounded apical dome, the tip. Once the trichoblast becomes committed to root hair fonnation, it no longer divides. The root hair cell has a migrating nucleus and a complex cytoskeleton. It has a varied cell wall. It is easy to observe through differential interference contrast microscopy because there are no other cells around it to disturb the image. Cytoplasmic streaming is exceptionally clear, and amyloplasts and even mitochondria and endoplasmic reticulum can be seen without reporter labelling in some species. Root hair mutants are easy to distinguish and catalogue. Plant honnones are involved in their growth and development. It is thus an almost ideal plant cell for experimental manipulation and observation. The root hair is also involved in interactions with soil microbes, as you will learn from later chapters of the book.

It has been known for a long time that the majority of plant viruses contain RNA and in the past decade and a half it has been realized that many have genomes consisting of three molecules of single-stranded RNA with positive polarity. Among these are viruses belonging to four groups recognized by the International Committee for Virus Taxonomy: the Bromovirus and Cucumovirus groups whose genomes are encapsi dated in small icosahedral particles or the Ilarvirus and alfalfa mosaic virus groups with spheroidal or bacilliform particles. In addition to their tripartite genomes, these viruses share a number of other properties and it has been proposed that they should perhaps be grouped in a single virus family for which the name Tricornaviridae has been suggested, the tri indicating the tripartite nature of the genome, the co emphasizing the cooperation of the three genome parts required to initiate infection, and the rna indicating that the genome is composed of RNA. Viruses of this "family" are less uniform in their biological proper ties. A number of them are widespread, causing very destructive plant diseases. Viruses such as those of cucumber mosaic and alfalfa mosaic have very extensive host ranges and are responsible for serious crop losses in many parts of the world. Others such as prunus necrotic ringspot or prune dwarf viruses are more restricted in their host ranges but never theless infect important perennial hosts such as stone fruits and reduce productivity considerably."

This volume presents the papers given at the meeting "Estuarine Management and Quality Assessment" held at Trinity College, Dublin in September 1983. The meeting was organised by the Environmental Sci ences Unit, TCD and the Estuarine and Brackish-Water Sciences Associ ation and was attended by delegates from the United Kingdom, Ireland, France, Holland and Portugal. The theme for the meeting was deliberately chosen in an attempt to bring together the various disciplines and interests in the field of estuarine quality, and the extent to which this objective was met may be judged from the diversity of the contributions. The meeting was arranged under three sub-headings which could be roughly summar ised thu- a) Modelling - as representative of the engineering hydrodynamicist approach. b) Impact - as representative of the biologist-type approach. c) Management - attempting to reconcile the different approaches to, and demands on, the estuary. In fact, since most contributions overlapped into the other two categories, the order in this volume has been changed somewhat from the meeting, and we feel that this book may be fairly presented as one unit. Contributions for which it was not possible to give full transcripts have been included, for completeness, as abstracts. In each session, an invited speaker summarised the state of the art, and the other speakers followed up by describing some new approach to or refinement of the problem."

The role of arthropods in forest ecosystems is poorly understood. Yet such knowledge may be critical in order to explain fully the fundamental forces that shape the structure and regulate the functioning of such ecosys tems. There are numerous hypotheses about the roles of various arthropods, but few, if any, of these hypotheses have been rigorously tested. Some, however, have been repeated so often and so widely that they are now accept ed by many as unequivocal fact. Nothing could be further from the truth. Forest arthropods which derive most of their sustenance from plants are usually specially adapted for feeding in one of three subsystems-the above-ground plant system, the soil-litter system, or the aquatic stream system. Plant-feeding arthropods in the soil-litter and stream systems are primarily saprophous although many consume significant amounts of microorganisms. Research on the role of arthropods in each of these three subsystems has historically been provincial. Until very recently there has been little effort to collate, assimilate, and syn thesize the plethora of findings in even one of these systems-rnuch less all three. This Symposium (at the 15th International Congress of Entomology, Washington, D.C. August 19-27, 1976) was organized for the specific pur pose of promoting scientific synthesis. It fulfills one of the first requirements in such endeavors; namely, the juxtapositioning of current knowledge and hypotheses so that similarities can be perceived, insights can be de rived, and more elaborate conceptual constructs can be built."

One of the most fundamental aspects of the auditory system is its frequency selectivity - the ability to resolve a complex sound into frequency compOhents. This ability plays a role in many aspects of auditory perception, including: the masking of one sound by another; the perception of pitch for pure tones and complex tones; the perception of timbre; the perception of the relative phase of components in complex sounds; and the perception of loudness. Over the last decade, there have been considerable advances in our understanding of frequency selectivity, both at the physiological and psychophysical level, and rapid progress continues to be made. This book summarizes the proceedings of a NATO Advanced Research Workshop on Auditory Frequency Selectivity which was held in Wolfson College, Cambridge from June 23rd to 27th, 1986. The Workshop brought together leading researchers from all disciplines relevant to the topic, with the aim of reviewing and consolidating the latest research findings, and identifying areas of uncertainty or controversy where further research is needed. The book is aimed primarily at research scientists and research students in the fields of psychology, audiology, auditory physiology, biophysics, medicine, acoustical engineering, noise control, communication and speech science. It should also be useful for advanced undergraduates in these disciplines. A feature of the book is that it includes summaries of the discussions which followed the presentation of each paper at the Workshop.