Pattern and Process in a Forested Ecosystem

Pattern and Process in a Forested Ecosystem

256 Pattern and Process in a Forested Ecosystem. F.H. Bormann and G.E. Likens. Springer--Verlag, Berlin, 1979, 253 pp. US $23.10 This book brings to...

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Pattern and Process in a Forested Ecosystem. F.H. Bormann and G.E. Likens. Springer--Verlag, Berlin, 1979, 253 pp. US $23.10

This book brings together the results of experimental studies on forest ecosystems at the Hubbard Brook area in northern New Hampshire, U.S.A. At this site an a t t e m p t has been made to assess the effect of deforestation on the hydrology and mineral balance of small (16ha) catchment areas. The main results can be simply stated: less water was lost from the deforested area by evaporation and so the streamflow increased substantially. At the same time, the loss of mineral nutrients dissolved in the streamflow was greatly increased. Experimental studies on whole ecosystems are difficult to mount. For reasons of scale it is n o t possible to design properly replicated plots; instead the approach must be to choose adjacent and similar small catchments for the " t r e a t m e n t " and the "control". Moreover it is difficult to know if these areas are representative of the forest as a whole, and how far the results can be extended to apply to forests anywhere in the world. Intuitively one feels that extrapolation to other forests may be possible only in a rough qualitative manner as the response to deforestation will depend largely on the local climate, topography and the nature of the soils. The authors consider the results in relation to the ecosystem concept. The title of the book is taken from the classic paper of the botanical ecologist A.S. Watt, and the text is influenced by the ideas of Eugene Odum and R a y m o n d Margalef. A hydrologist or even a forester may not be familiar with ecological concepts like biotic regulation and ecosystem maturity and he will probably ponder over the meaning of many of the terms like 'dead biomass'. I hope this will n o t detract from the value of the book. My own feeling is that a brave a t t e m p t has been made to take knowledge from different disciplines and present an integrated view. A quotation from A.S. Watt is made at the beginning of Chapter One: "As T.S. Eliot said of Shakespeare's work, we must know all of it in order to know any of it". Philosophically, this is an interesting stance and provides justification for integration. However, in practice we can never know all about an ecosystem. Ipso facto, perhaps we can never know any of it? I found much interesting reading in the book, but I t h o u g h t proper organisation of the material was at times lacking. In the first chapter reference is made to JABOWA, a computer model of the growth of northern hardwood forests. JABOWA is n o t described in detail and the reader is unsure of the extent to which it is being relied upon throughout the text. Consequently, there is sometimes difficulty in knowing whether the results referred to in the book are actual observations or whether they are JABOWAed, t h a t is, dependent on model calculations. A more straightforward account would be better. Chapters 2--6 deal with the results at different stages in the process of recovery after deforestation; however, they are not in sequence -- chapter 2 is n o t about the Reorganisation Phase that immediately follows clear cutting but the much later Aggradation Phase. The reader's


progress through the b o o k can only be impaired by such organisational slips. At a scientific level the work would have benefited from more rigorous micrometeorological approach. It would have been nice to see h o w the albedo, surface resistance and components of the energy balance changed over the years following deforestation. On the other hand, when the Hubbard Brook experiment began in 1963 this approach was almost unheard of, so n o t surprisingly data are available for the Aggrading Phase only. In c o m m o n with other American authors, Bormann and Likens have n o t y e t adopted SI units of measurement (a small but irritating point). The last two chapters a t t e m p t to place the forest in context as a comp o n e n t of the landscape. Silvicultural and management practices are considered. Clear-cutting is said to be acceptable only when coupled with carefully designed safeguards which are listed as a code of practice. Suggestions for wise management of the landscape are made; for example, that only a proportion of all lands dedicated to forest utilization would be clear-cut at any one time. This desire to relate basic research to the practice of forestry is commendable, especially at a time when exploitation of the world's forests continues at such a fast rate. The w o r k described in this volume is u n d o u b t e d l y important and to gain wide readership it certainly is proper to present it as a b o o k in addition to the original papers scattered in several journals. More research of this type is required in other parts of the world, especially in the tropics, so that a full appreciation of forest management (or mismanagement) practices can be gained. The b o o k is well produced by Springer--Verlag, with ample illustrations and a good bibliography. J. GRACE (Edinburgh)

Environmental Impact Assessment. R.E. Munn (Editor). Wiley, Chichester, 1979, 190 pp., £7.50. The environment first became a matter of specific legislative concern in 1970. Since then various countries have enacted laws requiring that decisions on developments or land use shall be taken in the light of the environmental consequences. This entails explicitly stating what consequences are likely, as a preliminary to decision-making. The statement is called an Environmental Impact Statement, and the process of compiling it is Environmental Impact Assessment (EIA). Clearly EIA is an exercise in futurology, so it is unlikely to be an exact science. Other problems are as follows. H o w do we define the "environm e n t " ? Are we really interested only on those aspects which impinge on mankind's welfare, as distinct from Nature as a whole? Are social and economic impacts to be included, or only the biophysical? H o w do we rank impacts which are respectively, immediate, occurring in 10 years, 100 years or later? H o w can we compare the importance of preserving historic sites,