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Forest ecosystems in tropical africa
Forest Ecology and Management, 14 (1986) 235--239 Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands
235
Book Renews AFRICAN TROPICAL FORESTS
Forest Ecosystems in Tropical Africa. Orstom, Unesco, Paris, 1983. 473 pp., FF. 150,00, ISBN 92-3-202041-6, Unesco ISBN: Orstom 2-70990681-3. This book is part of a series of actions carried o u t b y UNESCO to organise and develop research on the natural resources o f the tropical world and to publish regular status reports. At UNESCO's and PNUE's initiative a report on the state o f the tropical forest ecosystems in the world had been put together and published in 1978-79. The present report consists of the gathered d o c u m e n t s and the specific contributions concerning Africa. The participation of the Tropical Forest Technical Centre, the Land Resources Division of the U.K. and the Office for Overseas Scientific and Technical Research (ORSTOM), which co-publish the present book, has been particularly helpful. Forests are the main natural form o f vegetation in humid and subhumid tropical areas; their role is of major importance for the equilibrium o f the environment and because of their economic worth, direct or indirect. Very often, information in this field is fragmentary, p o o r and badly publicized. The present book aims at offering a summary o f our knowledge o f African tropical forest ecosystems, their inhabitants and their m o d e o f exploitation. It brings o u t the missing points in this field and lists research to be carried out. Such work mainly concerns low-altitude, dense, humid forests and sometimes semi-deciduous forests, and rarely dry, dense forests or clear forests (Miombo). The fourteen chapters of part I deal with the description, functioning and evolution of tropical forest ecosystems. Evaluation of acreage, monitoring projects of the forest cover, and use of teledetection techniques form chapter 1. Chapter 2 reviews ecological conditions, and the place of tropical forest ecosystems in the biosphere, effects o f the forest on the various components o f the environment and the consequences o f changes in the vegetation. But ancient climatic changes have many times affected the vegetation deeply : paleoclimatology and paleogeography allow us to conclude on the relative instability of the main tropical ecosystems (chapter 3). The following t w o chapters (4 and 5) deal, first, with our knowledge of the flora and the distribution of families and genera in Africa and Madagascar, as well as a classification of various forest types; next, with the organisation, i.e. the architecture and structure of the forests. Several new publications dealing with quantitative analysis o f the forest look at those aspects. The next two chapters (6 and 7) deal with the fauna : paleogeography and animal auto-ecology. The lack of
236 knowledge on the biology of tropical species is emphasized; and a study of the interactions between tropical forest animals and problems arising from the manipulation of those ecosystems is given. Chapters 8 and 9 are devoted to the biology, regeneration and growth o f trees in natural forests, and their secondary changes; normal processes o f change and evolution, both in time and space; perturbations of an anthropic origin and reconstitution processes. The last five chapters deal with the forest ecosystem : primary productivity, the assessment of which implies several methodological problems; secondary productivity, for which very little information is available; water balance, soils, erosion, so many fields for which -- in spite o f important research efforts remain to be made (forest water dynamics, evolution o f cultivated mils, aggravation of the erosion problems . . . . ), degradation and biological cycles -- tropical forests present very specific characteristics on those points -pests and phytopathology of forests and plantations (chapter 14): major areas o f interest, although the incidence o f pests in little- or non-manipulated ecosystems is less than in the artificial ecosystems. The second part of the book deals with man and types o f exploitation of tropical forest ecosystems. The first four chapters (15--18) deal with d e m o g r a p h y o f forest populations, in which research b e y o n d simple censuses remain necessary: on nutrition because the situation in tropical forest ecosystems is generally bad; on health and epidemiology, because the forest is a special environment whose increasing changes m a y bring a b o u t a development o f some diseases; on human adaptation and physical condition of forest populations. Chapter 19 deal with human civilizations and society in the forest. It looks at population distribution in forest ecosystems as related to the specific characteristics o f the environment and its changes. The following chapter (20) is an assessment of the ways in which man uses forest ecosystems. The second part ends with a discussion o f preservation and protection policies and the management of forests, underlining their relationship with scientific and technical knowledge, as well as their economic implications. It is unfortunately impossible to give a summary o f the various chapters in detail. The plan of each is as follows : definition of set points; state o f the knowledge, with numerous references to fundamental research and more recent developments; gaps in our knowledge, necessary research, research priorities; selective bibliographical index containing the most important literature. This b o o k deals mainly with African forest ecosystems, but these are naturally placed in the larger c o n t e x t o f humid intertropical zones. A b o u t one half o f the forests in the world are tropical and 30% o f dense forests grow in Africa. Man has reduced by one third the surfaces of humid tropical forests. The dangers for o u r environment, in the broadest sense, o f overexploitation can be inferred from a perusal of the UNESCO and ORSTOM synthesis. It is a very topical reference work that is very useful to bring up to date and disseminate our knowledge; it is also an invaluable tool to work with in research and management o f the African tropical forest.
237 J. KOECHLIN Centre d'Etudes de Gdographie Tropicale Domaine Universitaire de Bordeaux 33405 Talence C$dex, France
THE INTERPRETATION OF ECOLOGICAL DATA
The Interpretation of Ecological Data: A Primer on Classification and Ordination. E.C. Pielou. Wiley, New York, NY, 1984. 263 pp., £34.50. ISBN 0-471-88950-4. Professor Pielou provides step-by-step explanations of the manipulation of field data sets achieved in the widely-used classification and ordination procedures. Help in this respect for those who want it is the book's aim. As a bridge between the data collector and the adviser on subsequent analysis the significance is greater: competence in the process in its entirety is regrettably rare among ecologists, and if books such as this help redress the situation, ecology must benefit. A writer as experienced as Professor Pielou may be expected to provide a book well balanced both in c o n t e n t and in sequence -- and she does. The principal chapters deal with classification and ordination, the latter preceded by a useful and straightforward outline of the matrix transformations routinely employed in data ordination. Extension to practices which combine classification and ordination ( o r d i n a t i o n - s p a c e partitioning) and to joint interpretation of data matrices (discriminant ordination) constitute two briefer final chapters. I hope there will not be disappointment at the restricted view of "interpretation". What is intended is made clear at the end of the introductory chapter, but many who take the book o f f the shelf for inspection will still be seeking clues on interpreting plotted ordinations or classifications. This is a book which fills a gap in the available literature. As such, it deserves wide circulation among aspiring quantitative ecologists. Unfortunately, there can be no d o u b t that the price will work against this. A few institutional library copies can hardly be the most effective way of exposing students, for example, to a very practical reference manual t h a t should be constantly within arm's reach. Typographically, the book approaches perfection and good attention to layout makes an excellent complement to a lucid text. JOHN B. HALL Department of Forestry and Wood Science, University College of No rth Wales Bangor, Gwynedd, LL5 7 2UW Great Britain
235
Book Renews AFRICAN TROPICAL FORESTS
Forest Ecosystems in Tropical Africa. Orstom, Unesco, Paris, 1983. 473 pp., FF. 150,00, ISBN 92-3-202041-6, Unesco ISBN: Orstom 2-70990681-3. This book is part of a series of actions carried o u t b y UNESCO to organise and develop research on the natural resources o f the tropical world and to publish regular status reports. At UNESCO's and PNUE's initiative a report on the state o f the tropical forest ecosystems in the world had been put together and published in 1978-79. The present report consists of the gathered d o c u m e n t s and the specific contributions concerning Africa. The participation of the Tropical Forest Technical Centre, the Land Resources Division of the U.K. and the Office for Overseas Scientific and Technical Research (ORSTOM), which co-publish the present book, has been particularly helpful. Forests are the main natural form o f vegetation in humid and subhumid tropical areas; their role is of major importance for the equilibrium o f the environment and because of their economic worth, direct or indirect. Very often, information in this field is fragmentary, p o o r and badly publicized. The present book aims at offering a summary o f our knowledge o f African tropical forest ecosystems, their inhabitants and their m o d e o f exploitation. It brings o u t the missing points in this field and lists research to be carried out. Such work mainly concerns low-altitude, dense, humid forests and sometimes semi-deciduous forests, and rarely dry, dense forests or clear forests (Miombo). The fourteen chapters of part I deal with the description, functioning and evolution of tropical forest ecosystems. Evaluation of acreage, monitoring projects of the forest cover, and use of teledetection techniques form chapter 1. Chapter 2 reviews ecological conditions, and the place of tropical forest ecosystems in the biosphere, effects o f the forest on the various components o f the environment and the consequences o f changes in the vegetation. But ancient climatic changes have many times affected the vegetation deeply : paleoclimatology and paleogeography allow us to conclude on the relative instability of the main tropical ecosystems (chapter 3). The following t w o chapters (4 and 5) deal, first, with our knowledge of the flora and the distribution of families and genera in Africa and Madagascar, as well as a classification of various forest types; next, with the organisation, i.e. the architecture and structure of the forests. Several new publications dealing with quantitative analysis o f the forest look at those aspects. The next two chapters (6 and 7) deal with the fauna : paleogeography and animal auto-ecology. The lack of
236 knowledge on the biology of tropical species is emphasized; and a study of the interactions between tropical forest animals and problems arising from the manipulation of those ecosystems is given. Chapters 8 and 9 are devoted to the biology, regeneration and growth o f trees in natural forests, and their secondary changes; normal processes o f change and evolution, both in time and space; perturbations of an anthropic origin and reconstitution processes. The last five chapters deal with the forest ecosystem : primary productivity, the assessment of which implies several methodological problems; secondary productivity, for which very little information is available; water balance, soils, erosion, so many fields for which -- in spite o f important research efforts remain to be made (forest water dynamics, evolution o f cultivated mils, aggravation of the erosion problems . . . . ), degradation and biological cycles -- tropical forests present very specific characteristics on those points -pests and phytopathology of forests and plantations (chapter 14): major areas o f interest, although the incidence o f pests in little- or non-manipulated ecosystems is less than in the artificial ecosystems. The second part of the book deals with man and types o f exploitation of tropical forest ecosystems. The first four chapters (15--18) deal with d e m o g r a p h y o f forest populations, in which research b e y o n d simple censuses remain necessary: on nutrition because the situation in tropical forest ecosystems is generally bad; on health and epidemiology, because the forest is a special environment whose increasing changes m a y bring a b o u t a development o f some diseases; on human adaptation and physical condition of forest populations. Chapter 19 deal with human civilizations and society in the forest. It looks at population distribution in forest ecosystems as related to the specific characteristics o f the environment and its changes. The following chapter (20) is an assessment of the ways in which man uses forest ecosystems. The second part ends with a discussion o f preservation and protection policies and the management of forests, underlining their relationship with scientific and technical knowledge, as well as their economic implications. It is unfortunately impossible to give a summary o f the various chapters in detail. The plan of each is as follows : definition of set points; state o f the knowledge, with numerous references to fundamental research and more recent developments; gaps in our knowledge, necessary research, research priorities; selective bibliographical index containing the most important literature. This b o o k deals mainly with African forest ecosystems, but these are naturally placed in the larger c o n t e x t o f humid intertropical zones. A b o u t one half o f the forests in the world are tropical and 30% o f dense forests grow in Africa. Man has reduced by one third the surfaces of humid tropical forests. The dangers for o u r environment, in the broadest sense, o f overexploitation can be inferred from a perusal of the UNESCO and ORSTOM synthesis. It is a very topical reference work that is very useful to bring up to date and disseminate our knowledge; it is also an invaluable tool to work with in research and management o f the African tropical forest.
237 J. KOECHLIN Centre d'Etudes de Gdographie Tropicale Domaine Universitaire de Bordeaux 33405 Talence C$dex, France
THE INTERPRETATION OF ECOLOGICAL DATA
The Interpretation of Ecological Data: A Primer on Classification and Ordination. E.C. Pielou. Wiley, New York, NY, 1984. 263 pp., £34.50. ISBN 0-471-88950-4. Professor Pielou provides step-by-step explanations of the manipulation of field data sets achieved in the widely-used classification and ordination procedures. Help in this respect for those who want it is the book's aim. As a bridge between the data collector and the adviser on subsequent analysis the significance is greater: competence in the process in its entirety is regrettably rare among ecologists, and if books such as this help redress the situation, ecology must benefit. A writer as experienced as Professor Pielou may be expected to provide a book well balanced both in c o n t e n t and in sequence -- and she does. The principal chapters deal with classification and ordination, the latter preceded by a useful and straightforward outline of the matrix transformations routinely employed in data ordination. Extension to practices which combine classification and ordination ( o r d i n a t i o n - s p a c e partitioning) and to joint interpretation of data matrices (discriminant ordination) constitute two briefer final chapters. I hope there will not be disappointment at the restricted view of "interpretation". What is intended is made clear at the end of the introductory chapter, but many who take the book o f f the shelf for inspection will still be seeking clues on interpreting plotted ordinations or classifications. This is a book which fills a gap in the available literature. As such, it deserves wide circulation among aspiring quantitative ecologists. Unfortunately, there can be no d o u b t that the price will work against this. A few institutional library copies can hardly be the most effective way of exposing students, for example, to a very practical reference manual t h a t should be constantly within arm's reach. Typographically, the book approaches perfection and good attention to layout makes an excellent complement to a lucid text. JOHN B. HALL Department of Forestry and Wood Science, University College of No rth Wales Bangor, Gwynedd, LL5 7 2UW Great Britain