A number of well-known forests have been the object of studies by ecological teams. Every ecologist is familiar with the names of forests such as Whytham Woods in England (Elton 1966), Solling in West Germany (Ellenberg 1971), Hubbard Brook in New Hampshire, U. S. A. (Likens et al. 1977, Bormann and Likens 1979), and ladra6s in Central Sweden (Persson 1980). The number of such team studies grew rapidly during the period of the International Biological Programme (Reichle 1981). Each of these forests represented aspects oflocal and general interest. The Niepolomice Forest in Southern Poland (Fig. 1) does not possess any spectacular features and it may be regarded as a typical forest of the lowlands of continental Europe. Situated in the Vistula River Valley, 20 km east of Cracow (50 Degrees07' N, 20 Degrees23' E) it consists of two major sections: an extensive pine forest of the Pino-Quercetum type, and a smaller, deciduous, oak-hornbeam- Fig. 1. The location of the Niepolomice Forest in Southern Poland VI Preface Tilio Carpinetum forest. This huge forested area (11,000 ha) owes its survival in one of the most densely populated parts of Europe to a long period of protection as a royal hunting ground. The period of royal protection ended abruptly at the turn of 20th century under the devastating blows of two world wars followed by perhaps an even greater danger, the effects of modern developments in heavy industry.

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."

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."

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."

The author has drawn together almost all published methods since 1975 on the determination of anions in all types of matrices. He presents the methods in a logical manner so that the reader can quickly gain access to the method and types of instrumentation available.

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.

The literature on the geology, chemistry, and biochemistry of phosphorus generally takes its mineralogy for granted. The in cidental information on phosphate minerals given in these texts is often obsolescent and inaccurate. The few mineralogical texts that have dealt comprehensively with the phosphate minerals have now become outdated, and typically present the essential information in a manner unsuitable for nongeological readers. This volume is intended as a ready reference for workers who require good basic information on phosphate minerals or their synthetic equivalents. The topics covered should appeal to geologists and geochemists, lithologists, environmental scientists and engineers, chemists and biochemists who have any interest in the intricate world of phosphorus. The hard tissues of many vertebrates and the many pathological calcifications consist mostly of phosphate minerals. The precipita tion of these compounds also plays a major role in the ecological cycling of phosphorus, and occasionally even dominates the behavior of many trace metals in many geochemical and biolog ical systems. Indeed, many pegmatitic phosphate minerals have acquired some notoriety because of the rarer trace metals which they tend to accumulate. With the commercialization of phosphate fertilizers since the early part of the 19th century, phosphate minerals have assumed an important role in industrial chemistry and agriculture. Clearly, the study of phosphate minerals is important from the economic, agricultural, environmental and (human and animal) health viewpoint."

Biologically active compounds isolated from microorganisms continue to be vital to the development of new drugs and agricultural chemicals. This book was prepared by current and past members of the laboratory of Dr. Satoshi Omura of the Kitasato Institute in Japan. Dr. Omura and his colleagues have discovered and studied a number of important antibiotics, and in their work they have pioneered new methods for screening microbes for interesting and important compounds. This book presents strategies and methods for identifying novel molecules with several types of biological activity. In addition, the book discusses the identification of microbial compounds of agrochemical importance, presents information on chemical screening methods, and concludes with chapters on microbial strain selection, fermentation technology, and genetic engineering of antibiotic-producing microorganisms. This book will be of great interest to scientists working in the very active and competitive fields of antibiotic and agrochemical discovery.

Five years have now passed since the first symposium on frankiae was held at Harvard Forest, Petersham, Massachusetts, USA and the inauguration of the term actinorhiza. Many advances have been made during these five years in our understanding of the actinorhizal symbioses. Evidence for this was provided by the papers presented at the Wageningen Workshop on Frankia symbioses, held in Wageningen at the Department of Microbiology of the Agricultural University. Most of these papers are now published in this volume of PLANT AND SOIL. We kindly acknowledge the assistance of Anton Houwers, editor of the journal, in planning, reviewing and publishing these studies. Although the papers presented at Wageningen described the active research areas, they also illuminated those aspects of these symbioses which remain beyond our understanding. Primary among the areas of our ignorance is the concept of species within the bacterial symbiont, Frankia. At present groupings of bacterial strains are based on cell chemistry, physiology, serology, DNA homology and symbiotic capa bilities (cross-inoculation). When these classification schemes are merged no clear species framework is obtained. Undoubtedly part of the difficulty is due to a lack of strains for analysis. Currently bacterial strains from only half of the actinorhizal symbioses known to exist, have been isolated and studied in pure culture. We must postpone there fore any comprehensive taxonomic classification until a larger majority of the symbioses are represented. Another research area wherein our understanding is insufficient is host-symbiont interaction."

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."

"Instead of dirt and poison we have rather chosen to fill our hives with honey and wax; thus furnisning mankind with the two noblest of things, which are sweetness and light." Mindful of Swift's dictum, this compilation is offered as an exhaustive coverage of a smallish literature on the synthesis and secretion of beeswax, its elaboration into combs and the factors which bear on the execution of these processes by honeybees. To codify any aspect of the biology of an animal of agricultural importance is to sift through myriad observations and experiments, centuries old, that come down to us enshrouded in the folk literature. It is evident that wars and languages have also acted as barriers to the dissemination of knowledge about honeybees. Thus, particular care has been given to the primacy of discovery and its con textual significance. I have endeavoured to not over-interpret data and to allow the authors' works to speak for themselves. I have also tried to indicate some of the more obvious gaps in our knowledge of honeybees in relation to wax and to suggest some directions as to where we might proceed, aided by discoveries made on other animals and plants. This was done to remind the seasoned bee-hand of our general neglect of beeswax biology, historically constituting less than a percentage point of the apicultural literature."

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.

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 "International Symposium on Scleroderris Canker of Conifers" held June 21-24, 1983 in Syracuse, New York was the result of mutual interest expressed by the USDA Forest Service, the Canadian Forestry Service, and the State Uni versity of New York College of Environmental Science and Forestry (SUNY ESF). The Symposium was an official function of the working party canker diseases (Scleroderris), Subject group S.2.06.02 Division II IUFRO. We wish to express our thanks to the USDA Forest Service, Research and the Canadian Forestry Service for financial support of the program, and SUNY ESF for hosting the Symposium. A major research program was launched in 1977 to study the biology of the European strain as found in North America. Support for this research resulted from spec i a 1 fund ing by the Congress of the United States to the USDA Forest Service, North Central Forest Experiment Station. Most of these funds were released as cooperative research grants to universities in the Lake States and the northeast. Many of the research papers delivered at this Symposium are the direct result of these research grants. While the Symposium deliberately emphasized the North American experience 'with Gremmeniella abietina in order to provide a focus for the meeting, we were anxious that this Symposium would also include studies from other countries.

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."

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 recogmtIon of the microcirculation as an ideal interdisciplinary meeting place for the life sciences is really a postwar phenomenon. The European and the American Societies more than any other organizations launched the idea, and the success of the European Society's International Meetings gave impetus to a growth of interest from a handful of specialists to the wide interdisciplinary study which microcirculation now represents. The meeting held in Canada in June 1975 was, however, the first truly international meeting devoted to the microcirculation. It, too, was a success from every point of view, and the exchange of knowledge and new ideas was rewarding. It is our present hope that the tradition of European meetings with their characteristic European flavor will continue, but larded by larger, international congresses conceived on a worldwide basis. For the present conference we were fortunate in the presence of Dr. B. Zweifach. He was once referred to as the "father of the microcircula tion." This claim, unfortunately, I cannot accept. That honor probably belongs to Harvey, who by one of the most brilliant strokes of inductive reasoning in medical history inferred the existence of capillaries though he could not see them. Ben Zweifach's role was rather that of the midwife, presiding at the birth rather than the conception. The baby he delivered long years ago has since thriven lustily and its growth is in no small measure due to the continuing zeal of Zweifach and his associates."

Acid rain is a serious international environmental problem. Scandinavian forests have suffered especially severe damage, and have been the focus of considerable research on the causes and impacts of atmospheric pollution. This book presents the results of long-term studies on acid rain in Norwegian forests. This research examined soil chemistry and biology; the impacts of acid rain on tree growth and nutrition; and its influence on ground vegetation, fungi, and seedling germination and development. Long-Term Experiments with Acid Rain in Norwegian Forest Ecosystems is a lasting contribution to the literature on acid precipitation, and will be of interest to researchers in ecology, air pollution, forestry and environmental chemistry.

This book consolidates the descriptive results of a pantropical project called Agroforestry Systems Inventory (AFSI), undertaken by the International Council for Research in Agroforestry (ICRAF) from 1982 to 1987. Since agroforestry was a relatively new term when the project was initiated, the main objective was to increase the understanding of and provide a state-of the-art information base on existing agroforestry systems. Therefore, the project was designed to systematically collect, collate, synthesize, and dissem inate information on existing agroforestry systems in developing countries. One of the major results of the project, descriptions of existing agroforestry systems, was published as a series of articles in Agroforestry Systems. These system descriptions form the bulk of this book. Other products of the project include a microcomputer database on agroforestry systems, practices and components, and voluminous unpublished reports and records. Perhaps the title of the book is misleading in that the book does not include or cover all existing agroforestry systems in the tropics and geographical regions in the tropics. Additionally, some of the systems described are outside the tropical boul;ldaries of 23. 5" Nand S latitudes. For the purpose of this book, the word tropics is used in a general sense to also include subtropical developing countries that have agro-ecological and socio-economic character istics and land-use problems similar to those of the countries within the geographical limits of the tropical belt."

The world population in 1950 was 2. 5 billion and is more than 5 billion today. The agriculture community, however, has responded remarkably well to meeting the increased need for food and fiber. While the population growth during this period averaged almost 2% annually, the production of grain increased at an even faster rate. From 1950 to 1973, grain production increased 3. 1% annually, but slowed to about 2% from 1973 to 1984. There fore, as a whole, the world has more grain per capita available today than ever before. Several countries that were food importers just a few years ago are food exporters today. The world carry-over stocks today are the highest in years. While the major concern just a few years ago was whether the world could produce adequate food, the problem for many countries today is how to export their surpluses. Although the world as a whole has surplus food supplies, there are millions of people without adequate food to exist, and there are additional millions who have a bare subsistence diet at best. The average daily calorie supply for the developed countries is more than 3,300 per person, while the average for the developing countries is only about 2,200. The major global food produc tion problems have shifted from Asia to Africa, where malnutrition, poverty, and starvation are attracting world attention."

During the last decade, forest decline has become increasingly apparent. The decline in forest health was often reported to be associated with air pollution. The present study on Norway spruce stands in the Fichtelgebirge analyses various processes interacting within forest ecosystems. It covers transport and deposition of air pollutants, the direct effects of pollutants on above-ground plant parts, the responses of soil to acid rain, and the changing nutrient availability, and the accompanying effects on plant metabolism and growth. The role of fungi, microorganisms and soil animals in the decline of these stands is also assessed. The volume is concluded with a synthesis evaluation of the influence of different factors, and their interactions on forest decline.

ing damage ranged from odor. to general visual appearance. Attributes of seedling quality are categorized as either to cutting buds. to scraping bark to detect dead cambium. performance attributes (RGP. frost hardiness. stress resistance) One nursery reported using frost hardiness as an indicator of or material attributes (bud dormancy. water relations. nutrition. when to begin fall lifting. but none reported using it as an morphology). Performance attributes are assessed by placing indicator of seedling quality before shipping stock to customers. samples of seedlings into specified controlled environments and evaluating their responses. Although some effective short 23.4.3 Stress resistance cut procedures are being developed. performance tests tend Only three nurseries measure stress resistance. They use to be time consuming; however, they produce results on whole the services of Oregon State University and the test methods plant responses which are often closely correlated with field described in 23.2.3. One nursery reported that results of stress performance. Material attributes. on the other hand. reflect tests did not agree well with results of RGP tests and that RGP only individual aspects of seedling makeup and are often correlated better with seedling survival in the field. Most stress poorly correlated with performance. tests are conducted for reforestation personnel rather than for Bud dormancy status seems to be correlated. at least nurseries."