This book is directed at foresters who work, or have an interest, in the developing world, and at development analysts and theorists who are concerned with the forestry sector. Most readers will be aware that in recent years, some fundamental changes in thinking about the development process in very poor countries have occurred. At one level, the underdevelopment problem has been explained as a lack of absorptive capacity, or implementation ability in very poor countries. However, it now seems that these are only symptoms of a more profound ailment in the whole economic structural and philosophical approach to development. The idea that poor countries could transform their economies through an accelerated process of industrialisation has proved largely incorrect, or at least highly premature. Within the rural sector, emphasis on productivity and aggregate income growth have been shown to have had little effect or, worse still, negative effects, on the burgeoning group of poor and landless rural dwellers.

Soil is formed from physical and chemical weathering of rocks - processes described historically because they involve eons of time-by glaciation and by wind and water transport of soil materials, later deposited in deltas and loessial planes. Soil undergoes further transformations over time and provides a habitat for biological life and a base for the development of civilizations. Soil is dynamic -always changing as a result of the forces of nature and particularly by human influences. The soil has been studied as long as history has been documented. Numerous references to soil are found in historical writings such as Aristotle (384-322 B. c. ), Theophrastus (372-286 B. c. ), Cato the Elder (234-149 B. C. ) and Varro (116-27 B. c. ). Some of the earliest historical references have to do with erosional forces of wind and water. The study of soils today has taken on increased importance because a rapidly expanding population is placing demands on the soil never before experienced. This has led to an increase in land degradation and desertification. Desertifica tion is largely synonymous with land degradation but in an arid land context. Deterioration of soil resources is largely human induced. Poverty, ignorance, and greed are the indirect causes of desertification. The direct cause is mismanage ment of the land by practices such as overgrazing, tree removal, improper tillage, poorly designed and managed water distribution systems, and overexploitation."

Behavioural Mechanisms of Food Selection examines animals belonging to diverse trophic groups, from carnivores, herbivores, micro-algal grazers, to filter-feeders and detritus-feeders. In the past Optimal Foraging Theory has been applied to all these groups, but in different ways and in disci plines that rarely overlap. Here concepts and developments hitherto scattered in the literature are drawn together. This uniquely broad synthesis captures the state of the art in the study of diet selection and prescribes new objectives in theoretical development and research.

This book brings together research into the process of stream acidification and its impact on Welsh surface waters, carried out over the past decade or so. It is perhaps surprising that not until the 1980's was clear evidence of stream acidification assembled. In Wales, concerns over pollution had focused water quality sampling principally on the areas of traditional heavy industry and large urban popula tions served by inadequate sewerage systems and sewage disposal arrange ments. Mistakenly, it had been assumed that, with its prevailing westerly winds, Wales would receive precipitation substantially unpolluted by the industrial and urban emissions from Britain and mainland Europe. Assurance of the high quality of Welsh upland streams, the traditional nursery ground of salmonids, was eroded particularly by studies in the vicinity of Llyn Brianne reservoir in the catchment of the River Tywi of Central Wales. These demonstrated a clear correspondence between the biological quality and fisheries of streams in the catchment and aspects of stream chemistry, par ticularly pH, aluminium and calcium on the one hand, and catchment land use on the other. It is salutary to record that the first signals were of an inexplicable failure of the runs of migratory salmonids into the upper catchment, occupied by the Llyn Brianne reservoir and its influent streams, and the failure to restore the fishery by re-stocking with eggs and fry. Only then did the significance of the recent decline in some other upland lake and reservoir fisheries in Wales become apparent.

Roger C. Dahlman Environmental Sciences Division U.S. Department of Energy Washington, D.C. The potential for humans to alter Earth's atmosphere has been recognized since the end of the 19th century when Arrhenius estimated that a doubling of atmospheric carbon dioxide could alter the atmospheric radiation balance and raise average global temperature. Today, atmospheric CO concentrations play an important part in the 2 climate-change debate. Sources and sinks of CO associated with land use can be 2 significant determinants of the rate and magnitude of atmospheric CO change. 2 Combustion of fossil fuels and the deforestation associated with land-use change both contribute CO to the atmosphere; in contrast, biological processes on land create 2 potential sinks for the excess CO . Thus, land-use change and associated biological 2 processes become important elements in assessments of future atmospheric CO 2 increase; land-cover properties also affect the Earth's albedo, which is a climate feedback.

change is simply described by the rate of income and rate of loss. Our home's energy budget, our firm's inventory, our nation's debt, and humanity's numbers all have accounts that change at rates that are equal to the inputs minus the outputs. Jenny's "system view" of the soil was carried into the fertile fields of Midwestern American prairies from the laboratories of Switzerland in the late 1920s. Jenny's rate equations provided the other paradigm or world view that, I recall, brought us to the threshold of systems ecology as it later evolved in the second half of the twentieth century. As if world renown in the specialties of pedology and soil chemistry were not enough for one lifetime, excerpts below remind us that Hans Jenny has also been a perceptive outdoor field ecologist since his early Alpine expeditions with Braun Blanquet in the mid 1920s. Jenny's ecosystem studies in the pygmy forest, a further classic example of a soil-plant system "run down" over hundreds of thousands of years since its origin, continue to occupy some of the vigorous retirement time near his farm in Mendocino County. But each specific, quantitative case study, and each research area conserved (with additional hard work) for further study by future generations, fits into Jenny's coherent world view. It is that view, and its legacies of discovery and of tangible landscape preserves, which we are privileged to share with their originator in this volume."

In continuation of Volumes 8, 9, and 22 on in vitro manipulation of plant protplasts, this new volume deals with the regeneration of plants from protoplasts and genetic transformation in various species of Actinidia, Amoracia, Beta, Brassica, Cicer, Citrus, Cucumis, Duboisia, Fragaria, Glycine, Ipomoea, Lactuca, Lotus, Lycopersicon, Manihot, Medicago, Nicotiana, Petunia, Phaseolus, Pisum, Prunus, Psophocarpus, Saccharum, Solanum, Sorghum, Stylosanthes, and Vitis. These studies reflect the far-reaching implications of protoplast technology in genetic engineering of plants. They are of special interest to researchers in the field of plant tissue culture, molecular biology, genetic engineering, and plant breeding.

Geoffrey R. Dolby, PhD One of the principal characteristics of a scientific theory is that it be falsifiable. It must contain predictions about the real world which can be put to experimental test. Another very important characteristic of a good theory is that it should take full cognisance of the literature of the discipline in which it is embedded, and that it should be able to explain, at least as well as its competitors, those experimental results which workers in the discipline accept without dispute. Readers of John Parks' book will be left in no doubt that his theory of the feed ing and growth of animals meets both of the above criteria. The author's knowl edge of the literature of animal science and the seriousness of his attempt to incor porate the results of much previous work into the framework of the present theory result in a rich and imaginative integration of diverse material concerned with the growth and feeding of animals through time, a theory which is made more precise through the judicious use of mathematics. The presentation is such that the key concepts are introduced gradually and readers not accustomed to a mathematical treatment will find that they can appreciate the ideas without undue trauma. The key concepts are clearly illustrated by means of a generous set of figures. The crux of the theory comprises three differential Eqs. (7. 1-7."

At last geochemists are offered one comprehensive reference book which gives the Eh-pH diagrams for 75 elements found in the earth's surface environment, including transuranic and other radioactive species. For each of these newly calculated diagrams short explanatory texts are added. For the first time the primary elements are considered in water with metal, sulfur, carbon, and other species as appropriate. Furthermore, based on these figures and up-to-date thermodynamic data presented in this reference, researchers can predict the behavior of elements in the surface environment. Geoscientists, chemists and environmental agencies will also benefit from several brief texts on the importance of various elements to problems of radioactive waste disposal.

It is widely recognized that spiral grain in trees severely reduces the value of sawn timber through warping and loss of strength, and that it also causes problems for other wood uses as diverse as transmission poles or plywood. Yet, paradoxically, there are highly valued grain patterns including wavy and interlocked grain, whose origins in the cambium invite direct comparison with those of spiral grain, so that many authorities believe them to be related phenomena. In recent years this concept has prompted extensive research into the anatomy, genetics, and physiology of all such grain patterns in wood. As a result it has become apparent that tree cambia provide excellent systems through which to study the origins of stem polarity and the complex processes of morphogenetic control in plants. Beside these and other pressing topics for research, the book examines methods of measuring grain deviations, and considers their influence on wood properties, on the economics of timber production, and on wood manufacturing.

This book had its genesIs In the frustrations of the editors in locating authoritative, up-to-date material for an interdisciplinary graduate course in mammary gland biology, lactation, and breast-feeding. As we turned to the original literature several reasons for the dearth of usable material became clear: (1) In the areas of mammary gland biology and physiology, particularly as they relate to the human, reviews simply have not kept up with current research, which has in the last two decades provided tremendous insight into the mechanisms of milk secretion and its control. (2) The lack of interest in human milk as infant food inhibited researchers until very recently from investigating human lactation. (3) Much of the relevant clinical information remains anecdotal with little scientific basis. In this book we have tried to present the fundamentals of mammary gland physiology at the organismic and cellular levels in a form readily understood by physicians, scientists, and other professionals. This basic information is accompanied by authoritative reviews of the nutritional and immunological properties of human milk and by clinically relevant chapters designed to help health care professionals deal with the medical problems of the breast-feeding mother and her infant. We have strived in these chapters for up-to-date, authoritative, but readable accounts. In so far as possible we have avoided areas where much of our understanding rests on speculation. In the clinical domain this was not always possible because of a lack of solid, scientific information about breast-feeding.

A large proportion of the world's population is directly involved in agriculture, many of them as small businessmen. Each of these businessmen applies his skill and resources day in, day out, to produce food and raw materials. All of them to a greater or lesser extent operate in a changing environment to which they must adjust. Many aspects of the environments of agricultural institutions by the decisions of other people; in the marketplace, are influenced in ancillary industries, in research institutes and places of learning and in Government organisations that create and implement agricultural policy. Improvements in the quality of decisions made by those who manage all the various parts of the agricultural system can have a major impact on the quality of everyone's life. How can such improvements be achieved? This book is based on the belief that a grasp of concepts or principles can add a great deal to the understanding and management of agricultural systems of all kinds. It therefore attempts to transmit some ideas and observations about management in agriculture. It is not about techniques nor about the particular problems of a specific type of agriculture. Its aim is to promote reflection, thought and discussion by professional people whose decisions influence the performance of agricultural VII V11l PREFACE systems. As such, the book attempts to convey only the -central concepts of management in as simple a language as possible.

This volume summarises the result of an interdisciplinary research programme entitled Rehabilitation of the Atmosphere of the New States of Germany - Effects on Terrestrial Ecosystems'. Before the unification of Germany, emission loads of SO2 and dust particles were up to 18-fold higher in East than in West Germany. However, emission rates have decreased significantly since reunification in 1990, due to the breakdown of a large number of industrial and particularly lignite- fired powerplants and the implementation of clean air technologies. In order to study the effects of these dramatic changes in atmospheric chemistry on terrestrial ecosystems, comprehensive field studies were conducted in pine forest ecosystems along an historic gradient of atmospheric deposition rates in the northeastern lowlands of Germany. The fast and dramatic reduction of dust particle and SO2 emissions offers a unique opportunity to test the role of SO2 and alkaline particle deposition with regard to changes or damage to forest ecosystems and whether the forest stands return to a state of resilience. In this respect, this ecosystem experiment can be looked upon as a roof experiment without a roof.

Although the physiology of the menstrual cycle appears clear and easily explained by a balance in the concentration of various sex steroid hormones, numerous details of its mechanism are still poorly understood and little is known about the relationship among clinical events, plasma hormone concentrations, molecular impacts on target tissues and their regulation. In the following chapters, the authors have attempted to establish a correlation between endometrial histology and well-understood physiologic events of the menstrual cycle. They have provided up-to-date information on the effects of various hormones and combinations of hormones on the endometrium. The interdependence of endometrial morphology, molecular biology, endocrinology and physiology, provides grounds for a better understanding of the complex mechanism of the menstrual cycle, and sheds some light on its pathophysiology. Such an approach adds ariother dimension to interpretation of many menstrual abnormalities and numerous aspects of infertility in women with normal physiognomies and apparently regular menstrual cycles. The pathologist must be aware of these new concepts since a knowledge of functional changes reflected in hormone serum levels and sex steroid receptor concentrations allows a mare detailed analysis and a better interpretation of the structural features of the endometrium. This information placed in the proper clinical context can help the gynecologist provide optimal therapy. The reader will find a valuable reference for a synthesis of clinical, morphological, and biochemical data related to the menstrual cycle and its aberrations.

During the last decade it has become clear that bacteria-plant interactions play an important role in agricultural science. In particular, symbiotic nitro gen fixation, plant tumorigenesis, and plant pathogenic bacteria have been extenSively investigated. Therefore, several of my colleagues suggested the importance of organizing a specialized symposium on the "Molecular genetics of the bacteria-plant interaction." This symposium was held in Germany, at the University of Bielefeld, in the autumn of 1982. The International Program Advisory Board, together with the National Organizing Committee, initially decided to concentrate on the following three topics: 1. Rhizobium-plant interaction 2. Agrobacterium-plant interaction 3. Plant pathogenic bacteria In retrospect, these topics proved to be most popular: Nearly all important groups working in this field contributed to the Bielefeld Symposium. The papers presented are now published as the Proceedings. It will be obvious that this book represents the most comprehensive collection of papers describing the molecular genetics of the bacteria-plant interaction. Scientists, as well as students, can use this book to learn about the basic principles and the current ideas that have recently been developed in this growing research area. The Symposium was financed by the Bundesministerium ftir Forschung und Technologie (Federal Ministry of Science and Technology). I express on behalf of the Organizing committee its sincere appreciation to this sponsor, without whom the Symposium would not have been possible. In addition, the help of several industrial companies is acknowledged."

Until relatively recently the valuable tropical montane cloud forests (hereaf ter usually referred to as TMCFs) of the world had scarcely come under the assaults experienced by the downslope montane and lowland forests. TMCFs are not hospitable environments for human occupation, and their remoteness (except in places near Andean high mountain settlements and in the Ethiopian Highlands) and difficult terrain have given them de facto protection. The ad jacent upper montane rain forests have indeed been under assault for timber, fuelwood, and for conversion to grazing and agriculture for many decades, even centuries in the Andes, but true cloud forest has only come under ex ploitation as these lower elevational resources have disappeared. They have also been "nibbled" at from above where there have been alpine grasslands under grazing pressure. Increasingly now, however, these cloud forest eco systems are being fragmented, reduced, and disturbed at an alarming rate. It is now becoming recognized that steps must be taken rapidly to increase our understanding of TMCF and to achieve their conservation, because: their water-capture function is extremely important to society; * their species endemism is high; they serve as refugia for endangered species being marginalized in these environments by increasingly transformed lower elevation ecosystems; they are relatively little studied; yet, their value to science is extremely high; they have low resilience to disturbance; vii viii Preface and many other reasons, which will be discussed subsequently in this publi cation.

With one new volume each year, this series keeps scientists and advanced students informed of the latest developments and results in all areas of botany. The present volume includes reviews on structural botany, plant physiology, genetics, taxonomy, and geobotany.

Compared with forces occurring in soil mechanics problems in civil engineering, the forces that are applied to soil in farming operations generally have a short duration, less than a few seconds, a small loaded area, no more than a few square decimeters, and small intensities, 10 bar being a high value. On the other hand, soil properties vary widely between those of a weak mud and a stone-like dry soil. Tillage and related applications of force to soil are practiced worldwide in farming. Tillage operations are performed on one hectare of land for every three human beings. This means that for the food production for each individual daily, something like one cubic meter of soil is stirred, or about 20 times his body weight. Theoretical knowledge of this most common human activity, which largely determines the surface shape of the fertile part of the earth, is still very limited. In this book the authors have tried to give an outline of the present state of the art. One of the starting points was a course in soil dynamics taught by the authors at the Agricultural University at Wageningen, The Netherlands. We hope to reach interested readers who have no more theoretical knowledge than high school level, as well as readers who want to go beyond the level of a third year university student. For the chapter on wheels and tires we received substantial support from F. G. J. Tijink of the Tillage Laboratory at Wageningen.

Latest techniques for the analysis of plant cell or tissue structure and the registration of physiological pathways are topics of this volume. The subjects include: - Laser Doppler Vibrometer Measurements of Leaves; - Laster Physical Methods. Laser Microprobe Mass Spectrometry; - Triplet States in Photosynthesis: Linear Dichroic Optical Difference Spectra via Magnetic Resonance; - Fast Atom Bombardment Mass Spectrometry; -Microdissection and Biochemical Analysis of Plant Tissues; - Photoacoustic Spectroscopy - Photoacoustic and Photothermal Effects; - Membrane Operational Impedance of Spectra of Plant Cell.

Since the founding of the People's Republic of China in 1949there has been a rapid advance in climatology in China. The number of climatological stations has increased from less than 100 to more than of Chinese climatologists covers various 2,000, and the research work fields. The climate of China is no longer just a description of the average weather for an area or locality, but covers many fields such as the monsoon climate, the fluctuation of climate, the spatial and temporal variations of the climatic elements and physical and dynam ic climate. Four books on the climate of China, written in Chinese, have been published so far. There is, however, no excellent book written in English on the climate of China, although Volume 8 of the World Survey oj Climatology, dealing with the climates of northern and eastern Asia, edited by H. Arakawa in 1969, contains a chapter on the climate of China and Korea written by LE. M. Watts. The data sources for China are based mainly on observations from 1940-1952 and the climatological charts of China published by the Central Weather Bureau of China in 1953 and 1955. This monograph on The Climate ojChina by Prof. Dr. M. Dom ros and Prof. Peng Gongbing is the first comprehensive and advanced book in English on the climate of China."

It is apparent that wilt diseases continue to be a major problem in crop production because of the number of crops affected, the number and genetic variability of pathogens involved, and their widespread occurrence throughout tropical and temperate regions under a variety of cropping systems. It is also apparent, however, that new understandings and approaches, often in combinations not previously discerned, offer exciting new prospects for research, understanding and practical control methods. The current state-of-the-art and fields for further studies were discussed by researchers actively engaged in a wide range of areas from ecological studies of physical and biological factors in the host-parasite-environmental interactions in the soil, through physiological and biochemical studies of host-parasite recognition and interaction that determine relative colonization of the host, through genetic-molecular studies of these interactions, to the most practical field studies of disease control.

Global attention in scientific, industrial, and governmental commUnItIes to traces of toxic chemicals in foodstuffs and in both abiotic and biotic environ ments has justified the present triumvirate of specialized publications in this field: comprehensive reviews, rapidly published progress reports, and archival documentations. These three publications are integrated and scheduled to pro vide in international communication the coherency essential for nonduplicative and current progress in a field as dynamic and complex as environmental con tamination and toxicology. Until now there has been no journal or other publica tion series reserved exclusively for the diversified literature on "toxic" chemicals in our foods, our feeds, our geographical surroundings, our domestic animals, our wildlife, and ourselves. Around the world immense efforts and many talents have been mobilized to technical and other evaluations of natures, locales, magnitudes, fates, and toxicology of the persisting residues of these chemicals loosed upon the world. Among the sequelae of this broad new emphasis has been an inescapable need for an articulated set of authoritative publications where one could expect to find the latest important world literature produced by this emerging area of science together with documentation of pertinent ancil lary legislation."

This thorough study is an assessment of the risks involved with the deliberate release of microorganisms modified by means of genetic engineering. Major emphasis is on European cooperative research projects such as the ones on Rhizobium and Baculovirus. Further contributions cover aspects of soil microbiology, genetic transformation in soil, molecular and plasmid genetics, horizontal spread of plasmids, as well as administrative, regulative and legal aspects in relation to possible releases.

By their powers of reason scientists will be able to extract from nature the answers to their questions. From: Critique of Pure Reason, 1781 Immanuel Kant (1724-1804), German Philosopher History is a composite of stories. The history of the biological disciplines has been written by all those who opened the gates of new knowledge by generating ideas and the experiments to support them. Previous authors have attempted various approaches to the history of virology, as is reflected in the numerous books and book-series issuing from the publishing houses. This volume is an attempt at a compre hensive yet compact survey of virology, which has meant penetrating the rigid limits of the separate disciplines of biology in which virologists have worked. Writing this history of experimental virology was really a search for the origins and for vital signposts to portray the wide scope of the knowledge attained thus far. This was done in com plete awareness of the fact that every presentation depends heavily upon the perspective of the observer, and of necessity communi cates only a part of the whole. The present scientific story hopes to recount the most important knowledge achieved during this past century - the first century of the exciting developments in virology."

An extraordinary development of the knowledge, concepts and biomedical applications has occurred during the past two decades in the biological sciences, including the Reticuloendothelial Sys- tem (RES). For example, it is now widely recognized that distinct classes of cells are involved in the recognition of "exogenous" invaders of the body such as microorganisms and other foreign an- tigens, as well as of "endogenous" parasites represented by trans- formed neoplastic cells and altered "self" antigens. Prominent among cell populations involved in such recognition of antigens and subsequent immune responses are those constituting the RES. In recent years, there has been much discussion and indeed contro- versy as to what constitutes such a system and even whether the term "RES" is appropriate. Some investigators feel that the phago- cytes are the most important cells of the RES as they playa major role in the defense mechanism of the host. Mononuclear phagocytes include tissue macrophages ~s well as circulating monocytes and their precursors. Although phagocytosis is a major functional ac- tivity, it is only one of their several functions. The important role of phagocytes and other mononuclear cells in antibody forma- tion, cell-mediated immunity, specific and non-specific resistance to microorganisms and tumor cells, as well as homeostatic adjust- ments in general has become the focus of attention for many inves- tigators.