Biotechnology has come to a stage where, by replacing some of the age old practices of breeding, it can produce novel and improved plants and animals that can better serve human beings and their purposes. The techniques of cellular and subcellular engineering, such as gene splicing and recombinant DNA, cloning, hybridomas and monoclonal anti bodies, production of human insulin, protein engineering, industrial fermentation, artificial insemination, cryopreservation and ovum trans fer, plant tissue culture and somatic hybridization, nitrogen fixation, phytomass production for biofuels etc have advanced greatly in the past decade, due to the availability of better equipment and the consolida tion of knowledge. Product orientation has removed biotechnology from the area of pure academic interest to one of utility where the final product is a spur to action. Businesses have started pouring money into projects, which has aided greatly in improving equipment, information exchange, and arousing the interest and imagination of the public. The common goal of science, industry and the public opens wide vistas and great hopes for biotechnology. The business of biotechnology addresses itself to issues of factory farming, technology transfer, joint ventures, international cooperation and to specific topics as well as the produc tion of diagnostic kits. Industry is particularly concerned with the phar maceutical field and microbial biotechnology from which profitable return can accrue. Commercial interests have led to better management practices and systematisation."

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."

This volume arises from an International Symposium on Flow and Transport in the Natural Environment held in Canberra, Australia, in September 1987. The meeting was hosted by the CSIRO Division of Environmental Mechanics (now the Centre for Environmental Mechanics) to mark the opening of the second stage of its headquarters, the F.C. Pye Field Environment Laboratory, twenty-one years after the opening of the first stage. Those twenty-one years have seen much progress in our understanding of the physics of the natural environment and the occasion provided an ideal opportunity to review advances in our knowledge of flow and transport phenomena, particularly with regard to flow and transport in soils, plants and the atmosphere. The contents of this volume are based very closely on the Symposium's program. Undoubtedly, our choices of topics were idiosyncratic, but we believe that those we have selected exhibit progress, innovation, and much scope for practical application. Rather than being encyclopaedic, we have sought to deal with thirteen selected topics in depth.

This publication comprises the proceedings of the first International Conference devoted to the structural roots of trees and woody plants. 'The Supporting Roots - Structure and Function, ' 20-24 July 1998, Bordeaux, France. The meeting was held under the auspices ofIUFRO WPS 2. 01. 13 'Root Physiology and Symbiosis, ' and its aim was to bring together scientific researchers, foresters and arboriculturalists, to discuss current problems in structural root research and disseminate knowledge to an audience from a wide disciplinary background. For the first time in an international conference, emphasis was placed on presenting recent reseach in the field of tree anchorage mechanics and root biomechanics. The way in which tree stability can be affected by root system symmetry and architecture was addressed, as well as how movement during wind sway can influence the development and shape of woody roots. The role of different nursery and planting techniques was discussed, in relation to effects on root system form and development. Root response to different environmental stresses, including water, temperature, nutrient and mechanical stress was addressed in detail. The structure and function of woody roots was also considered at different levels, from coarse to fine roots, with several papers discussing the interaction between roots and the rhizosphere. One of the conference highlights was the presentation of new methods in root research, by a series of workshops held at LRBB-INRA, Pierroton, on the northern border of the Gascony forest.

Pesticides in ground, surface and drinking water are a hot topic under continuing discussion. This complete and authoritative volume draws together information on all key issues on the fate and behaviour of pesticides in water systems. The scope of the practice-oriented contributions and the eminence of contributing authors make it an important source for researchers and practitioners in the plant protection and crop science field.

Proceedings of the Physiology Working Group Technical Session Society of American Foresters National Convention, Portland, Oregon, USA, October 16-20, 1983

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."

The change in greenhouse operation and technology in the last 20 years has been unprecedented. Photoperiodic control, mist propagation, green house cooling, clean stock programs, CO injection, to name a few, have 2 all been inaugurated as regular greenhouse practices in this time. The introduction of new markets, new production centers, shifts in public attitudes, and the realization that greenhouse production is not simply growing crops, but the management of an enterprise in which people work, h ve combined to make this agricultural practice a challenging and rewarding vocation. The greenhouse grower, manager, and student who are training for this vocation have not had an up-to-date text book for many years. It has been our goal to bring both published and unpublished work together in this book, and to provide a bench mark from which we can continue to move forward. It is not until a process of writing a text begins that one fully realizes how far we have come-and where we need to go. It is with some sadness that we realize that this book is not likely to remain long as an expression of the state-of-the-art. We do not expect it to be easy reading; for new terms, new technology, and new ways of doing things are not always easy."

Provided here is a comprehensive treatise on all aspects of dielectric properties of wood and wood products. The topics covered include: Interaction between electromagnetic field and wood. - Wood composition and dielectric properties of its components. - Measurement of dielectric parameters of wood.- Dielectric properties of oven-dry wood. - Dielectric properties of moist wood. - Effect of different kinds of treatment on dielectric properties of wood. - Dielectric properties of bark. - Dielectric properties of wood-based materials. - Recommendations for determination of dielectric parameters of wood based materials and for their use in calculations. Several appendices comprise reference data onthe dielectric characteristics of wood and wood-based materials in the wide range of frequencies, temperatures, and moisture content.

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."

These are the proceedings of an Advanced Research Workshop (ARW), sponsored by the NATO Science Panel, entitled "Pest Control: Operations and Systems Analysis in Fruit Fly Management." The ARW was held in Bad Windsheim, Germany during the week of 5 August 1985. The purpose of the ARW was to bring together scientists who are interested in fruit fly problems, but who usually do not have an opportunity to speak with each other, for an intense week of interdisciplinary collaboration. In particular, the group present at the ARW contained a mix of biologists, field ecologists, mathematical modellers, operational program managers, economists and social scientists. Each group has its own professional meetings at which fruit fly problems are discussed, but the point of the ARW was to learn about the problem from the perspective of other fields, which are equally important for the ultimate management of the fruit fly problems. (A list of attendees follows this preface. ) It appears that the ARW successfully met its objective of bringing together a group for interdisciplinary considerations of the problems; I hope that the proceedings do as well. The ARW was structured with formal lectures in the mornings and workshops in the afternoons. For the morning lectures, four different topics were chosen: 1) basic biology and ecology, 2) trapping and detection, 3) control and eradication, and 4) policy issues. Each morning, one lecture from each area was presented.

th st On June 20 and 21 1985 the third workshop on "Azospirillum: Geneties, Physiology, Eeology" took place at the University of Bayreuth, West Germany, organized by the geneties department. There were about 80 partieipants, who eame from German research institutions, from other European eountries, from India, Egypt, North and South America. The former workshops had taken place in Bayreuth too in 1981 and 1983 respeetively, henee the organizers eould draw on the experienees then obtained. Azospirilla have, during the past 12 years, found an ever inereasing seientifie interest, beeause first, these soil baeteria earry the genetie information for binding moleeular nitrogen from the air, and second, they live in elose vieinity to the roots of grain erops and forage grasses. By exploi tation of these two properties, it is hoped to develop inoeulation proeedures in soils poor in nitrogen. The reports on the first afternoon foeussed, as aresult of the Bayreuth research interest, on genetie approaehes.

Throughout the world natural forest ecosystems have been, and are being massively disrupted or destroyed. The boreal forests of Canada are no more immune to man's intervention than the tropical rain forests of Africa, and the day is rapidly approaching when natural forest ecosystems, undisturbed by man, will be found only as remnants in national parks and other protected areas. Yet where they continue to exist these ecosystems are an extraordinarily rich, though relatively neglected source of data that illuminate many aspects of the classic theory of evolution. The subject matter of this book is not, however, confined to natural forest ecosystems. Forest ecosystems under varying degrees of management, and man made forests are also a rich source of information on ecological genetics. In general, however, it can be said that the published evidence of this fact has not yet significantly penetrated the botanical literature. All too frequently it is confined to what might be termed forestry journals. It is hoped that this book will to some extent redress the balance, and draw attention to a body of published work which not only provides a basis for the rational management and conservation of forest ecosystems, but also complements the literature of ecological genetics and evolution. The first draft of Chapters I to V was written in German by the senior author and translated by E. K. MORGENSTERN of the Canadian Forestry Service."

The cambium has been variously defined as follows: "The actively dividing layer of cells that lies between, and gives rise to, secondary xylem and phloem (vascular cambium)" (IAWA 1964); "A meristem with products of periclinal divisions commonly contributed in two directions and arranged in radial files. Term pre ferably applied only to the two lateral meristems, the vascular cambium and cork cambium, or phellogen" (Esau 1977); and, "Lateral meristem in vascular plants which produces secondary xylem, secondary phloem, and parenchyma, usually in radial rows; it consists of one layer of initials and their undifferentiated deriva tives" (Little and Jones 1980). Clearly, the cambium is a diverse and extensive meristem, and no one defini tion will encompass all manifestations of what anatomists consider cambium. Its diversity and extent are further exemplified by a single plant, such as a temperate zone tree, in which procambium is initiated in the embryo and perpetuated throughout every lateral, primary meristem before giving rise to cambium in the secondary body. The cambium thereafter performs its meristematic task of producing daughter cells that differentiate to specialized tissue systems. The cam bium, however, does not remain static. Its derivatives vary either in form, or TImc tion, or rate of production at different positions on the tree, with age of the tree, and with season of the year. Moreover, the cambium responds both to internal sig nals and to external stimuli such as environment or wounding."

After UNCED (United Conference on Environment and Development, Rio de Janeiro, July 1992), a second edition of Desertification was necessary. About 150 corrections, amendments and additions take scientific progress into account. The author also presents an updated chapter in which the results of UNCED are analyzed.
This book aims at an understanding of what is commonly called "desertification" - a term which is proposed to be replaced by "land degradation." Each level of technology, excessive or insufficient, creates its own mismanagement. This is reflected in an increase in land degradation and eventually a decrease in soil productivity. The benefit to the reader is an awareness of the ecozones and a global overview of the phenomena, mechanisms and existing solutions.

Since the first edition of our book "Tissue Culture in Fores try" in 1982 we have witnessed remarkable advances in cell and tissue culture technologies with woody perennials. In addition to forest biologists in government, industry, and universities, we now have molecular biologists, genetic engineers, and biochemists using cell and tissue cultures of woody species routinely. There fore, the time has come for an update of the earlier edition. In our present effort to cover new developments we have expanded to three volumes: 1. General principles and Biotechnology 2. Specific Principles and Methods: Growth and Development 3. Case Histories: Gymnosperms, Angiosperms and Palms The scientific barriers to progress in tree improvement are not so much lack of foreign gene expression in plants but our current inabili ty to regenerate plants in true-to-type fashion on a mas sive and economic scale. To achieve this in the form of an appro pr iate biotechnology, cell and tissue culture will increasing ly require a better understanding of basic principles in chemistry and physics that determine structural and functional relationships among molecules and macromolecules (proteins, RNA, DNA) within cells and tissues. These principles and their relationship with the culture medium and its physical environment, principles of clonal propagation, and genetic variation and ultrastructure are discussed in volume one."

This book tells a story of a large lake affected by agricultural and urban activities that have led to severe eutrophication problems with nuisance blue-green algal blooms. Although it is a case study of Lake Ringsjoen (southern Sweden), the background, problems and measures are applicable to many lakes throughout the world. From a limnological point of view, the Lake Ringsjoen story began more than 100 years ago, and during the last 20 years the sampling program has been intense, providing a unique data set on how a lake responds to human activities. However, the Lake Ringsjoen story is not only a case study, but also a historical record of the development of ecological theory and its application. Hence, the lake has been subject both to an extensive nutrient reduction programme and a biomanipulation by means of fish reduction. Here we aim at combining the unique limnological data set with the eutrophication process, the nutrient reduction programme and the biomanipulation in order to apply our empirical knowledge to future lake management measures.

The world needs for food and fiber continue to increase. Population growth in the developing countries peaked at 2. 4% a year in 1965 and has fallen to about 2. 1%. However, in many developing countries almost half the people are under 15 years of age, poised to enter their productive and reproductive years. The challenges to produce enough food for this growing population will remain great Even more challenging is growing the food in the areas of greatest need. Presently the world has great surpluses of food and fiber in some areas while there are devastating deficiencies in other areas. Economic conditions and the lack of suitable infrastructure for distribution all too often limit the alleviation of hunger even when there are adequate supplies, sometimes even within the country itself. World hunger can be solved in the long run only by increasing crop production in the areas where the population is growing most rapidly. This will require increased efforts of both the developed and developing countries. Much of the technology that is so successful for crop production in the developed countries cannot be utilized directly in the developing countries. Many of the principles, however, can and must be adapted to the conditions, both physical and economic, of the developing countries.

The introduction of chain saws and tractors in the early 1950's marked the beginning of a change in tree harvesting techniques from the old manual methods to mechanized operations. It was followed by a rapid evolution both technically and systematically. Hence, the requirements for improved know ledge of operational efficiency also increased. Changing relations between Man, machines and environment brought about new experiences and awareness of a physiological and ergonomic nature. Improved knowledge of both machine technology and planning of work on a small or large scale has grown increa singly important for an efficient utilization of expensive machines and other equipment. The need for a textbook on tree harvesting techniques including expe riences made in recent years is enhanced. The book presented here is prima rily based on lectures given on the subject of Forest Techniques at the Faculty of Forestry at the Swedish University of Agricultural Sciences and after modifications also at the University of Nairobi (Kenya). Thus, the book is written primarily for students at the faculties and institutes of forestry. However, it is also useful for persons actively occupied in forest operations. The presentation of this book in its original Swedish version in 1972 created a considerable interest in the preparation of a condensed edition in English. Thus interest has been expressed in Finland, Norway, Holland, Canada, U.S.A., Brazil, Japan, Poland, Scotland and Yugoslavia."

JOHN G. HILDEBRAND Research on insect olfaction is important for at least two reasons. First, the olfactory systems of insects and their arthropod kin are experi mentally favourable models for studies aimed at learning about general principles of olfaction that apply to vertebrates and invertebrates alike. Detailed comparisons between the olfactory pathways in vertebrates and insects have revealed striking similarities of functional organisation, physiol ogy, and development, suggesting that olfactory information is processed through neural mechanisms more similar than different in these evolution arily remote creatures. Second, insect olfaction itself is important because of the economic and medical impact of insects that are agricultural pests and disease vectors, as well as positive impact of beneficial species, such as the bees and moths responsible for pollination and production of honey. The harm or benefit attributable to an insect is a function of what it does - that is, of its behaviour - which is shaped by sensory information. Often olfaction is the key modality for control of basic insect behaviour, such as ori entation and movement toward, and interactions with, potential mates, appro priate sites for oviposition, and sources of food. Not surprisingly, therefore, much work on insect olfaction has been motivated by long-term hopes of using knowledge of this pivotal sensory system to design strategies for mon itoring and managing harmful species and fostering the welfare of beneficial ones."

Research on the interactions of plants and phytopathogenic fungi has become one of the most interesting and rapidly moving fields in the plant sciences, the findings of which have contributed tremendously to the development of new strategies of plant protection. This book offers insight into the state of present knowledge. Special emphasis is placed on recognition phenomena between plants and fungi, parasitization strategies employed by the phytopathogenic fungi, the action of phytotoxins, the compatibility of pathogens with host plants and the basic resistance of non-host plants as well as cultivar-specific resistance of host plants. Special attention is paid to the gene-for-gene hypothesis for the determination of race-specific resistance, its molecular models and to the nature of race non-specific resistance as well as the population dynamics of plants and the evolution of their basic resistance.

The lntergovernmental Panel on Climate Change (IPCC) has recently summarized the state ofthe art in research on climate change (Climate Change 1995). The most up to date research findings have been divided into three volumes: * the Science ofClimate Change (working group I), * the Impacts, Adaption and Mitigation of Climate Change (working group II), and * the Economic and Social Dimensions ofClimate Change (working group III) There is a general consensus that a serious change in climate can only be avoided if the future emissions of greenhouse gases are reduced considerably from the business as usual projection and if at the same time the natural sinks for greenhouse gases, in particular that of CO , are maintained at the present level or 2 preferrably increased. Forests, forestry and forestry industry are important parts of the global carbon cycle and therefore they are also part of the mitigation potentials in at least a threefold way: 1. During the time period between 1980 and 1989 there was a net emission of CO from changes in tropical land use (mostly tropical deforestation) of 2 1. 6 +/- 1 GtC/a, but at the same time it was estimated that the forests in the northem hemisphere have taken up 0. 5 +/- 0. 5 GtC/a and additionally other terrestrial sinks (including tropical forests where no clearing took place) have been a carbon sink ofthe order of l. 3 +/- l.

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