This is a stimulating tale of the interplay of observation, experimentation, working hypotheses, tentative conclusions, niggling and weightier doubts and great aspirations, on the part of some score of students, on varied ecological and other aspects of the regime and role of fire in relevant biomes and ecosystem- mainly in South Africa - and on other pertinent features of fire ecology. The impressive contents is a tribute to conveners and authors alike. One can expect a profound range and depth ofinvestigation and interpretation, a closeknit fabric of knowledge, delicately interwoven with wisdom, an exposition and quintessence of information. Admipable is the collective vision responsible for selecting appropriate topics: the wide sweeps of the brush picturing the nature of the biomes; ably describing the fire regimes - whether in grassland, savanna, fynbos or forest; skillfully defining the effects of such regimes - according to ecosystem - upon aerial and edaphic factors of the habitat, upon constituent biota, individually, specifically and as a biotic community; elucidating the basic implications in the structure and dynamics of the plant aspect of that community ... and unravelling to some degree the tangled knot of the conservation and dissipation of moisture and nutrients. Moreover, gratitude is owed for efforts exerted to understand the interplay of fire and faunal behaviour and dynamics as well as composition, together with the principle of adaptive responses of organisms of diverse kinds.

Due to the long-term planning horizons and the great variety of natural, economic, and operational hazards affecting forest ecosystems, uncertainty and multiple risk are typical aspects of forest management. Applications of risk analysis are surprisingly rare, in spite of the rich assortment of sophisticated forest planning tools that are available today. The objective of this particular volume within the book series Managing Forest Ecosystems is to present state-of-the-art research results, concepts, and techniques regarding the assessment and evaluation of natural hazards and the analysis of risk and uncertainty relating to forest management. Various aspects of risk analysis are covered, including examples of specific modelling tools. The book is divided into three sections covering ecological perspectives, applications in engineering and planning, and methods applicable to economics and policy.

In terrestrial ecosystems, soil microorganisms and soil animals are essential for litter degradation, soil formation and the availability of nutrients and trace elements. The measurement of biological soil parameters allows a rapid evaluation of the effects of chemical and physical influences due to pollutants or soil management.
This book introduces a number of well proved methods for the analysis of carbon, nitrogen, phosphorus and sulfur cycles. It focuses further on the determination of the number and biomass of microorganisms, algae and animals in the soil. Particular emphasis is placed on the comprehensible and complete description of the experimental procedures.

Because of the magnificent response to the call for papers for the 7th International Biodeterioration Symposium held at Cambridge, UK, some difficulties have been experienced in the editing of these proceedings. The numbers of papers submitted exceeded expectation and because of this it has been necessary to accommodate those not actually in the proceedings into the International Biodeterioration journal. A small number of papers were not suitable for publication and were therefore eliminated. Many authors disregarded the guidelines laid down for the length of submitted papers. However, every attempt has been made to accommodate the maximum number of contributions in the proceedings. The original selection included those which most nearly conformed to the length requirement. Even so this has meant, in many cases, cutting down the text, eliminating tables and/or illustrations and pruning the reference list. When references have been trimmed a note has been included to the effect that an extended list may be obtained from the author/senior author. Where it was not possible to carry out these procedures without seriously altering the text and the import of the paper they have been included amongst those to be published in the journal International Biodeterioration. The exceptions to the procedures outlined above are the invited review papers which have been presented in full. Happily, the authors have been conscientious in keeping to the guidelines laid down for these contributions.

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, systematics, ecology, and vegetation science.

The 12th International Conference on Plant Growth Substances was held from 26th to 31st August 1985 in Heidelberg, F. R. G., under the auspices of the IPGSA (International Plant Growth Sub stances Association) and the University of Heidelberg in its 599th year. As many as 750 participants from 40 countries all over the world attended the conference, including guests and staff members of the local organizers. Fine days provided an excellent background for a fruitful and pleasant meeting and all the activities accompanying the scientific programme. During the conference all current aspects concerning growth substances were treated. Altogether the par ticipants presented 207 oral reports organized in four parallel sessions and about 300 posters, for which 2 hours' poster sessions were reserved each day. The conference gained in perspective from the arrangement of five workshops in which special aspects and the most recent results could be presented by specialists in the particular fields. The topics of the workshop were: actual methods of hormone detection (orga nizer H. Kende), auxin transport (organizer R. Hertel), growth sub stances and tumour formation (organizer J. Schroder), evolution of the hormone system (organizer W. Jacobs) and problems of ap plication (organizer J. Jung). The abstracts of all presentations were collected in a Book of Abstracts available during the conference, giving a rough surveY of the whole field of plant growth substances in its present state."

Presented here is another classic from this series and deals with general aspects of micropropagation of plants for commercial exploitation. It includes chapters on setting up a commercial laboratory, meristem culture, somatic embryogenesis, factors affecting micropropagation, disposable vessels, vitrification, acclimatization, induction of rooting, artificial substrates, cryopreservation and artificial seed. Special emphasis is given on modern approaches and developing technologies such as automation and bioreactors, robots in transplanting, artificial intelligence, information management and computerized greenhouses for en masse commercial production of plants.

Man as a biological species and as a member of the community of organisms that has evolved over the billions ofyears on this planet has to face competition for his resources in the same way as any other species. In the course of evolution organisms have developed a fascinating variety of weapons, techniques and strategies in this competitive scramble for food and other essential resources and in se1f-defense against parasitism and predation. Among these, the biosynthesis of toxic molecules and their appropriate delivery in interspecific encounters has proved to be one of the most successful natural weapons and has been demonstrated in every branch of the evolutionary tree of all extant species. It is interesting to note that in this process of generating toxic molecules both natural se1ection by evolutionary processes and screening techniques by chemical industry have produced compounds with very similar target sites. The most potent of these compounds interfere with the normal signalling of nerve cells. Saxitoxin, tetrodotoxin, batracho- toxin, grayanotoxin, veratridine, aconitin, sea anemone venom and scorpion toxin are natural poisons which interfere with the same membrane bound protein as many potent synthetic insecticides such as DDT and the pyrethroids: the voltage-gated Na + channe1 in the nerve cell membrane. In several cases natural toxins have direct1y provided lead structures for successful chemical synthesis programmes in the insec- ticide industry. Eserine, nereistoxin and pyrethrum are outstanding examples.

Presented here is a comprehensive account of both theoretical and practical aspects of sugarcane production. The first of two parts of the book deals with origin, distribution, soil and climatic requirements, seed bed preparation, cultural and nutrient requirements, fertilization, irrigation, ratooning, weeds, pests, diseases, ripening, and harvest. In thesecond part, energy and fibre cane, cane development, and manufacturing techniques of sugar and by-products are treated in detail. This book will serve as a vademecum for cane growers, sugar and sugarcane technologists, students and teachers.

In his lectures my teacher Karl Magdefrau used to say that one only becomes a real plant scientist when one enters a tropical rainforest. For me this initiation occurred in 1969 in northern Queensland, Australia, and was associated with the greatest excitement. On another level it received confirmation when I set out in 1983 together with some friends and colleagues for the first detailed ecophysiological studies of epiphytes in the wet tropics in situ in the island of Trinidad and later for similar work in Venezuela. This then promoted the idea of organizing a special symposium on "The evolution and ecophysiology of vascular plants as epiphytes" during the XIV International Botanical Congress in luly 1987 in Berlin, and to ask some of the speakers to produce chapters for a small monograph on the interesting ecologically defined group of plants "epiphytes" as presented in this volume of "Ecological Studies." The enthusiasm of the participants of the symposium giving reports and adding to the discussion was most stimulating, and it appears that epiphytes might gain well-deserved, wider consideration in the future. The cooperation with the authors of this book was very pleasant and I appreciated the new contacts established with adepts of the "epiphyte community." The chapters were organized and arranged covering first more gen eral aspects with setting the scene in Chapter 1, the evolution of epi phytism in Chapter 2 and the role of CO -concentrating mechanisms in 2 Chapter 3."

Low temperature represents, together with drought and salt stress, one of the most important environmental constraints limiting the pro ductivity and the distribution of plants on the Earth. Winter survival, in particular, is a highly complex phenomenon, with regards to both stress factors and stress responses. The danger from winter cold is the result not only of its primary effect, i. e. the formation of ice in plant tissues; additional threats are presented by the freezing of water in and on the ground and by the load and duration ofthe snow cover. In recent years, a number of books and reviews on the subject of chilling and frost resistance in plants have appeared: all of these publications, however, concentrate principally on the mechanisms of injury and resistance to freezing at the cellular or molecular level. We are convinced that analysis of the ultrastructural and biochemical alterations in the cell and particularly in the plasma membrane during freezing is the key to understanding the limits of frost resistance and the mechanisms of cold acclimation. This is undoubtedly the immediate task facing those of us engaged in resistance research. It is nevertheless our opinion that, in addition to understanding the basic physiological events, we should be careful not to overlook the importance of the comparative aspects of the freezing processes, the components of stress avoidance and tolerance and the specific levels of resistance."

The first edition of this book was the first to provide an integrated description of sap ascension from an anatomical and functional point of view. The second edition opens with the three-dimensional aspects of wood anatomy. The cohesion-tension theory and new evidence are introduced in response to recent controversies over the mechanism of sap ascent in plants. The physiology, anatomy and biophysics of xylem dysfunction are discussed and new insights into hydraulic architecture are reviewed with special emphasis on physiological limits on maximum transpiration and how hydraulic architecture limits gas exchange, carbon gain and growth of plants. The text concludes with a description of xylem failure and pathology. The book highlights fascinating areas of current research with the aim to stimulate more work in the future.

This series is dedicated to serving the growing community of scholars and practitioners concerned with the principles and applications of environmen tal management. Each volume will be a thorough treatment of a specific topic of importance for proper management practices. A fundamental objective ofthese books is to help the reader discern and implement man's stewardship of our environment and the world's renewable resources. For we must strive to understand the relationship between man and nature, act to bring harmony to it and nurture an environment that is both stable and productive. These objectives have often eluded us because the pursuit of other indi vidual and societal goals has diverted us from a course of living in balance with the environment. At times, therefore, the environmental manager may have to exert restrictive control, which is usually best applied to man, not nature. Attempts to alter or harness nature have often failed or backfired, as exemplified by the results of imprudent use of herbicides, fertilizers, water and other agents. Each book in this series will shed light on the fundamental and applied aspects of environmental management. It is hoped that each will help solve a practical and serious environmental problem."

Succession-nothing in plant, community, or ecosystem ecology has been so elaborated by terminology, so much reviewed, and yet so much the center of controversy. In a general sense, every ecologist uses the concept in teaching and research, but no two ecologists seem to have a unified concept of the details of succession. The word was used by Thoreau to describe, from a naturalist's point of view, the general changes observed during the transition of an old field to a forest. As data accumulated, a lengthy taxonomy of succession developed around early twentieth century ecologists such as Cooper, Clements, and Gleason. Now, nearer the end of the century, and after much discussion concerning the nature of vegetation communities, where do ecologists stand with respect to knowledge of ecological succession? The intent of this book is not to rehash classic philosophies of succession that have emerged through the past several decades of study, but to provide a forum for ecologists to present their current research and present-day interpretation of data. To this end, we brought together a group of scientists currently studying terrestrial plant succession, who represent research experience in a broad spectrum of different ecosystem types. The results of that meeting led to this book, which presents to the reader a unique summary of contemporary research on forest succession.

In March, 1983 a workshop on Pollutants in Porous Media was hosted by the Institute of Soils and Water of the Agricultural Research Organi zation in Bet Dagan, Israel. At this workshop, the unsaturated zone be tween the soil surface and groundwater was the focal point of discus sions for scientists from various disciplines such as soil chemists, physicists, biologists and environmental engineers. Since then, the prob lem of soil and water pollution has only worsened as more and more cases of pollution caused by human activities including agriculture and industry have been revealed. A great deal of work has been carried out by environmental scientists since 1983 in elucidating the behavior of the many classes of pollutants and the complex physical, chemical, and bio logical transformations which they undergo as they move through the soil to the vadose zone and, in many cases, the groundwater. In light of this, it was felt that another meeting of specialists from the many disciplines which deal with this subject was necessary and so a Second International Workshop on the Behavior of Pollutants in Porous Media, sponsored by IUPAC (the International Union of Pure and Applied Chemistry) and IAHS (the International Association of Hydrological Sciences), was organized and held in the Institute of Soils and Water of the Agricultural Research Organization in Bet Dagan, Israel during 1987. June, The present volume is a selection of the talks presented at this second workshop and deals only with toxic organic chemicals in porous media."

It is enough to work on the assumption that all of the details matter in the end, in some unknown but vital way. Edward O. Wilson, Biophilia Advances in knowledge of northern ecology have been so rapid that to undertake a synthesis of all the literature now available would be a major enterprise, perhaps even a life's work, and so it must be considered permissible to fill in a few gaps, follow one's own inclinations, leaving comprehensive syntheses to those willing to undertake them. This is the rubric under which I have written, reporting some of the more interesting data I and others have obtained over the years, often diverging into discussions of plants, soils, climate, and faunal relationships which have perhaps not previously been dealt with extensively, or at least in quite the same way. This is purely intentional, since I find it difficult to summon up the needed enthusiasm, at this late hour, to write on topics which unfortunately for me have little attraction. I have thus written for the pleasure derived from depicting, perhaps at times as something of an impressionist, a fascinating biotic region, a captivating land, a collection of interesting ecological problems, environmental relationships to be discerned in part, perhaps understood to some small degree, perhaps one day to be modeled mathematically. As Leo Szilard once wrote: ': . . to be able to say even this much might be of some value" (Szilard, 1960).

Worldwide concern in scientific, industrial, and governmental com munities over traces of toxic chemicals in foodstuffs and in both abiotic and biotic environments 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 provide in international communication the coherency essential for nonduplicative and current progress in a field as dynamic and complex as environmental contamination and toxicology. Until now there has been no journal or other publication series reserved exclusively for the diversified literature on "toxic" chemicals in our foods, our feeds, our geographical surroundings, our domestic animals, our wild life, 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 authorita tive publications where one could expect to find the latest important world literature produced by this emerging area of science together with documentation of pertinent ancillary legislation."

Production of food to meet the demands of an ever-increasing human population in the world is the major task and challenge to agriculture today. The conventional methods of plant breeding alone can no longer cope with the situation. The success of any crop improvement program depends on the extent of genetic variability in the base population, but due to denuding of forests and agricultural land, the naturally occurring pool of germplasm is being depleted. An urgent need is therefore ap parent to create new variability and increase the genetic base of agricul tural crops. Agricultural biotechnology has progressed to a stage in the produc tion of plants where specific characteristics to improve their yield, ap pearance, disease-resistance, nutritional quality and adaptation to ad verse soil conditions can be built into the seed. This concept of built-in quality implies a continuous scientific endeavour to improve plant char acters using a wide range of possibilities, and it also implies a scrutiny of the materials and methods available in the world today."

A knowledge of forest site and forest productivity variables is fundamental to sound forest practice everywhere. The ability to identify sites and site problems correctly and manipulate productivity variables for maintenance or improvement of productivity is the basis of modern forest management. Although the basic facts regarding forest site and productivity apply throughout the world, the application of information and the response to manipulation vary greatly and depend on local forest conditions. The September 1981 World Congress of the International Union of Forest Research Organizations (IUFRO) in Kyoto, Japan was the occasion for the special meeting on Forest Site and Productivity sponsored by the IUFRO Site Group Sl.02. This meeting brought together forest site and productivity researchers from across the world to review current thought and the state of site research. Information not ordinarily available in one place was presented at this meeting. As organizer of the session, I decided to attempt to publish the papers in one volume. Arrangements were made with a publisher, Martinus Nijhoff, and also with the authors. The process of publication has taken longer than desirable, but the volume does appear at an opportune time coincident with the 1986 IUFRO World Congress in Yugoslavia. Material contained in this publication will set the stage for Site Group discussions at the 1986 meeting. This volume assembles the thought of forest research workers from many different countries and therefore many different kinds of forests.

Worldwide concern in scientific, industrial, and governmental com munities over traces of toxic chemicals in foodstuffs and in both abiotic and biotic environments 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 provide in international communication the coherency essential for nonduplicative and current progress in a field as dynamic and complex as environmental contamination and toxicology. Until now there has been no journal or other publication series reserved exclusively for the diversified literature on toxic" chemicals in our foods, our feeds, our geographical surroundings, our domestic animals, our wild life, 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 authorita tive publications where one could expect to find the latest important world literature produced by this emerging area of science together with documentation of pertinent ancillary legislation."

It is currently impossible to grow lichens under controlled conditions in the laboratory in sufficient quantity for physiological experiments. Lichen growth is slow and conditions which might accelerate the process tend to favour either the algal or fungal partner, resulting in the breakdown of balance symbiosis. Lichen physiologists are therefore forced to use field-grown material with all the problems associated with the unknown influences of unpredictable and unreproducible climatic conditions. Study of major biochemical topics, such as the nature of the carbohydrate and nitrogenous compounds passing between the symbionts, is less influenced by climatic conditions than the intrinsic nature of the symbionts and many advances have been made in these areas. Recently, the challenge of using field-grown plant material, the physiological status of which is intimately linked to environmental conditions, has proved to be a stimulus rather than a hindrance to a number of research groups. The occurrence of lichens in extreme habitats has prompted a number of field and laboratory studies with material from such diverse localities as the cold deserts of Antarctica and the temperate rain forests of the New Zealand bush. A comparative approach, using contrasted species or habitats from a particular geographical region has yielded much information and an appreciation of the variety of physiological adaptations which may exist. The close linkage between morphology and physiology is now being directly demonstrated, as is the relevance of ultrastructural information.

'frees contribute a major part of fuel, fodder and fruit, and are an im of bioenergy. They are now needed in large numbers more portant source than ever before for afforestation and social forestry, so that fast-grow ing and multipurpose trees assume great importance. After extensive in discriminate deforestation and rapid depletion of genetic stocks, efforts are now being made to evolve methods for clonal mass propagation of improved and elite trees. Production of short-duration trees with a rapid turnover of biomass, and induction of genetic variability through in vitro manipulation for the production of novel fruit and forest trees, which are high-yielding and resistant to pests and diseases, and trees which display increased photosynthetic efficiency are in demand. These objectives are well within the realm of horticultural and forest biotech nology. Some of the recent advances, such as the regeneration of com plete trees from isolated protoplasts, somatic hybridization, and the Agrobacterium-mediated transformation in various tree species have opened new vistas for the genetic engineering of fruit and forest trees. This book is a continuation of the earlier volume Trees I, and presents 31 chapters on fruit, forest, nut and ornamental trees, such as avocado, pineapple, crabapple, quince, pistachio, walnut, hazelnut, date palm, oil palm, cacao, rubber, maple, sweet-gum, poplars, birches, Chinese tallow, willows, oaks, paper mulberry, rhododendrons, Scots pine, Calabrian pine, Douglas-fir, redwood, ginkgo, cycads and some flowering trees."

At present, no single book adequately covers a basic understanding of wood book satisfies the need for such a work. It describes drying in practice. This the fundamental basis of kiln-drying technology, to enable forest companies to imFrove their drying operations as high-quality timbers become scarcer and of yesteryear can no longer be tolerated. Adaptive the wasteful practices is no longer good enough. Innovations change based on past experience of the material being dried and the processes require a sound understanding of drying. Newer techniques, such as the use of ultrahigh temperature sea soning and superheated steam under vacuum, require an even greater depth of physical understanding for these methods to be used effectively and economically. book provides a description of modern ideas about wood structure, This moisture movement and stress development, from which models of the drying process are developed to give the kiln operator important information about the course of drying under specified conditions, and thus a means is compared with practice wherever for rational process improvement. Theory possible."

The world population in 1930 was 2 billion. It reached 3 billion in 1960, stands at 4. 6 billion today, and is expected to reach 6 billion by the end of the century. The food and fiber needs of such a rapidly increasing population are enormous. One of the most basic resources, perhaps the most basic of all, for meeting these needs is the soil. There is an urgent need to improve and protect this resource on which the future of mankind directly depends. We must not only learn how to use the soil to furnish our immediate needs, but also ensure that the ability of the soil to sustain food production in the future is unimpaired. This is indeed a mammoth task; a 1977 United Nations survey reported that almost one-fifth of the world's is now being steadily degraded. The diversity of soil makes it cropland necessary for research to be conducted in many locations. There are basic principles, however, that are universal. This, Advances in Soil Sciences, presents clear and concise reviews in all areas of soil science for everyone interested in this basic resource and man's influence on it. The purpose of the series is to provide a forum for leading scientists to analyze and summarize the available scientific information on a subject, assessing its importance and identifying additional research needs. But most importantly, the contributors will develop principles that have practical applications to both developing and developed agricultures.

Advances in Rice Blast Research provides a complete overview of the research undertaken on the rice-blast pathosystem. This book gathers in one volume the most recent works on rice blast fungus genetics and molecular biology of pathogenicity, rice blast fungus population studies, and genetics and molecular biology of rice resistance to blast, including resistance gene cloning. It also presents the latest results on resistance breeding and resistance management strategies, epidemiology and disease management. This book is a must for plant pathologists and breeders working on rice blast and also to plant pathologists and breeders dealing with fungal diseases in general, because the rice-blast pathosystem is a model in plant pathology. Advances in Rice Blast Research provides a complete overview of the research undertaken on the rice-blast pathosystem. This book gathers in one volume the most recent works on rice blast fungus genetics and molecular biology of pathogenicity, rice blast fungus population studies, and genetics and molecular biology of rice resistance to blast, including resistance gene cloning. It also presents the latest results on resistance breeding and resistance management strategies, epidemiology and disease management. This book is a must for plant pathologists and breeders working on rice blast and also to plant pathologists and breeders dealing with fungal diseases in general, because the rice-blast pathosystem is a model in plant pathology.