Vegetation dynamics and global change

Vegetation dynamics and global change

86 Book Reviews gramming) that address forest ecosystem interactions and are more effective than “traditional” methods at including the ecosystem fu...

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86

Book Reviews

gramming) that address forest ecosystem interactions and are more effective than “traditional” methods at including the ecosystem function. The discussion includes optimization under conditions of risk and uncertainty, spatial optimization and multi-level optimization. Hof points out that ignoring randomness can have significant empirical consequences.The message is that a solution to an optimization problem ought not only to be optimal, but feasible as well. That aspect is included by sticking acceptable probabilities of feasibility on the alternative outcomes, e.g. biodiversity is included by the probability of acquiring different population levels. The impact of the spatial configuration of a management action on the concerned outputs is an important non-linear problem. The issue of spatial distribution is at stake for non-timber outputs where it is more important how a management action is spatially laid out than how many hectares are involved. Hof deals with the spatial problems by taking the departure in approaches that account for edge effects, and proceeds to more complicated habitat fragmentation and proximity effects. Hof makes a point of revealing that smallerscale analysis of single forests cannot simply be agglomerated into a larger-scale whole. He shows how a multilevel optimization (synonymous with a hierarchial optimization including a geographic hierarchy) might retain the advantages of the smaller-scale analysis and still obtain an integrated large scale plan that is not simply an agglomeration of the smaller-scale plans. Overall, the book relies heavily on mathematics, but John Hof has managed to maintain the balance of making his examples simple and understandable without neglecting his opinion that quantitative analysis, even in a complex form, should be applied in multi-resource management. The changing management philosophy in forestry, reflected in the global perception that sustainability is being re-defined from referring primarily to a “sustainable yield” to a “sustainable ecosystem management”, is nicely integrated in the book. The presentation and topics covered in the book make it relevant to all with an interest in

modem forest resource management. Addressing a wide target group, ranging from~graduate students and scientists to natural resource planners and modelers, Hof’s contribution is an important supplement to standard forest management texts. MICHAEL LINDDAL Royal P’eterinary and Agricultural L%iversity Unit qfF0restr.v 5 7 7’horvaldsensvej DK- I8 71 Frederihxberg C Denmark J.P. SKOVSC;AARD Danish Forest and Landscape Research institute Department ofForestry 16 Skovbrynet DK-2800 LYNGBY Denmark

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Vegetation Dynamics and Global Ctinge. Edited

by Allen M. Solomon and Herman H. Shugart. Chapman & Hall, New York and London, 1993, 338 pp*, price $22.50 (paperback), ISBN 0-412-03671-l (cloth), ISBN O412-03681-g (paper). This book brings together the ideas and results of a group of ecologists and modellers, who worked together at IIASA in 1988 and 1989 with the aim of constructing models of the terrestrial biosphere which could be used to explore the effects of climate change on ecosystems.This was an important endeavour then, which has gathered pace since under the umbrella of IGBF. The Framework Convention on Climate Change identifies the ability of ecosystemsto adapt as a criterion of acceptable climate change. Action on the control of greenhouse gas emissions by the signatories of the FCCC is, in effect, made contingent upon knowing the degree and rate of change beyond which ecosystemswill be irreversibly damaged. This book is therefore particularly valuable, especially as it contains reviews that will introduce readers to the subject. It pro-

Book Reviews

vides a foundation for those wishing to follow this fast-moving research area. Part I introduces the uninitiated to the greenhouse effect and the history of global ecological studies. Part II considers the responses of vegetation to climate change and, to a lesser extent, the important effects of vegetation on climate. The two subjects that receive the most thorough treatment are (i) the responses of plants to elevated CO, and the implications for vegetation development and the terrestrial carbon cycle, and (ii) the functional relationships between plant water relations, leaf area and vegetation height, which are so important in vegetation-climate interactions. Part III covers different aspects of obtaining, classifying, mapping and manipulating data on the vegetation cover of the earth. More questions are asked than answered concerning the use of remotely sensed data and how to progress beyond the use of static models of climate-vegetation relationships, such as the Holdridge and Box

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models, but this section provides the reader with a good background to what follows. The final Part of the book considers how to model vegetation responses to climate dynamically. There are chapters on modelling natural vegetation at the regional and stand scales and on modelling crop responses,and two thoughtful and contrasting chapters suggest different ways of using functional attributes to classify vegetation. Overall, the editors are to be commended on producing a book that is well balanced in its coverage of this broad subject. Most chapters have a summary, the book is indexed, and it is remarkably free of errors. The low price and scope of the book will surely mean that it is already on shelves in many offices as well as libraries. MELVIN G.R. CANNELL Institute of Terrestrial Ecology (NERC) Bush Estate Penicuik, Midlothian EH26 OQB UK