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Forest decline and air pollution: A study of spruce (Picea abies) on acid soils
92
Book reviews
of fertilizers and pesticides but there seems to be a strong influence from climate as well. Other chapters deal with other types of bloom, notably red tides caused by dinoflagellates and the bloom of the prymnesiophycean flagellate, Chrysochromulina polylepsis, which was such a nuisance in the Kattegat-Skagerrak area in 1988, as well as more general aspects. The situation seems to have been best summed up by L. B. Slobodkin. Referring back to G. E. Hutchinson's 'paradox of the plankton', which refers to the circumstance that, in general, numerous phytoplankton species are found to co-exist although ecological theory would lead us to expect that interspecific competition within a homegeneous body of water would result in the survival of only one, he points out that the blooms are the 'null case' of the paradox. Normally, the time scale of environmental change in open waters is shorter than that required for the process of competitive exclusion but if a water mass favourable to phytoplankton growth maintains its integrity for long enough for an initial inoculum to reach bloom proportions a unialgal population results. This leads to the thought that hydrography is the crucial factor for development of blooms, but, curiously, not a great deal is said about this. The work of the Plymouth group on the red tide associated with the shallow sea tidal mixing front off Ushant is not discussed. The view which emerged from the conference on which this book is based, that dramatic phytoplankton blooms result from the convergence of perhaps subtle but long-term anthropogenic and eutrophication effects with aperiodic environmental conditions, seems to put the emphasis on secondary factors. However, although no very clear explanation of 'novel' blooms is arrived at, there is much in this book--the chapter by J. McN. Sieburth and P. W. Johnson surveying the composition of the picoplankton, for example--which will be of value to biological oceanographers and phycologists as well as to those who have to cope with the untoward effects of blooms. G. E. Fogg
Forest Decline and Air Pollution: A Study of Spruce (Picea abies) on Acid Soils. Edited by E. D. Schulze, O. L. Lange & R. Oren. (Ecological Studies, Vol. 77, edited by W. D. Billings, F. Golley, O. L. Lange, J. S. Olson & H. Remmert). Springer-Verlag, Berlin, 1989. 475 pp. Price: DM298 (hardback).
This volume is an extraordinarily valuable addition to the Ecological Studies series and to the literature on forest ecosystems. The work conducted by the Bavarian Forest Toxicology Research Group between 1982 and 1988 in the Fichtelgebirge Forest (northwest Baria, FRG) is described in a series
Book reviews
93
of detailed papers and a final synthesis is presented. Since the initial observations of widespread forest decline in central Europe in the late 1970s, it has become increasingly clear that there has been, and continues to be, a range of species and regionally specific forest declines, rather than a single and irreversible 'Waldsterben' as was once feared. The work conducted in the Fichtelgebirge has been focused on two 30-year-old Picea abies stands on similar base rock and experiencing similar climatic conditions. At one of these stands (Wiilfersreuth) the trees are healthy while at the other (Oberwarmensteinach) the trees show type 1 decline of P. abies (Needle yellowing and Mg deficiency). As this work has gradually been presented to the scientific community at conferences and in the journals, there has been a recognition of the value of these intensive stand studies and a growing understanding of the complex decline sequence which has occurred in the Fichtelgebirge. In the present volume three introductory papers cover the chronological development of Forest Decline in the F R G and the evolution of the research in The Bavarian Forest, the vegetation of the Fichtelgebirge and, of considerable interest, a discussion of the potential and limitations of field studies of the type being described. The book then has five main Parts as follows: (1) air pollution: transport and deposition, (2) the role of fungi, microorganisms and soil animals, (3) direct effects of pollutants on aboveground plants, (4) soil responses to acid rain and associated effects on plants, and (5) processes leading to forest decline: a synthesis. The fourth part on soil responses is the longest, it being made up of nine papers. The various aspects are tied together well and reflect the development of the 'nutrient disharmony' as a broad unifying concept or 'composition of hypotheses' within which forest declines can be considered. The nutritional principles and the schematic model of elemental fluxes, compartments and regulating parameters in a forest ecosystem under the influence of air pollution (pictured on the front cover) have a much broader relevance than would be anticipated from a 'two-site' study, and benefit from the intensive studies of different species and forest areas which have been conducted by other groups over the same period. As a consequence of the intensive studies, including those described here, our understanding of forest ecosystems and their responses to stress has advanced considerably over the last 10 years. In the case of the Fichtelgebirge, it is fascinating to see how initial vague notions on the importance of the direct effects of SO 2, and possibly of O 3, led to work on decline symptoms (yellowing and needle loss), photosynthesis and elemental leaching from the canopy and then on to sulphate, nitrate and ammonia inputs and effects on soils and soil processes. These studies have provided an appreciation of the significance of nitrogen inputs, soil acidification and Ca/A1 ratios, and of the balance between
94
Book reviews
nitrogen, magnesium and other nutrients (Ca, K and P) in forest canopies. It is suggested that declines are associated with disharmony between uptake and demand for nutrients. The authors do not claim that all the answers have been found and give some useful pointers for current priorities. The book draws together the various Fichtelgebirge studies very well and puts them in context against the associated hypotheses which have been developed by T. Ingestad, B. Ulrich and others over the same period.
Peter Freer-Smith
Air Pollution and Forests Interaction Between Air Contaminants and Forest Ecosystems. (2nd Edition) By William H. Smith. Springer-Verlag, Berlin, 1990. 618 pp. Price: DM198.00. In 1972 W. H. Smith was asked to review the relationship between air pollution and forests for the American Association for the Advancement of Science and his efforts resulted in the publication of the first edition of 'Air Pollution and Forests..." in 1981. History has judged that this large task was fulfilled skilfully with the book becoming well known and much referred to. Part of the success of the first edition can be attributed to the structure within which the review was undertaken. This was to consider pollutant and forest interactions in three classes: Class I relationships by which low doses result in forests acting as sources and sinks, and experiencing beneficial effects or being unaffected; Class H relationships which occur when intermediate doses are experienced and may give subtle adverse effects on nutrition, metabolism, and entomological and pathological interactions; and Class III relationships when high doses result in acute damage and tree mortality. Each of these classes make up a section of the book and the sections have between two and nine chapters. The second edition adopts the same structure but with a better introduction and with the addition of a fourth section on 'Global Atmospheric Stress and Forest Risk Assessment'. This has chapters on climate change and on the role of air quality in influencing forest helath. The new edition has additional chapters within the original three sections; the review is still of temperate forests only (40 ° to 60°N) and is based almost entirely on North American work. Exceptions to this are the brief coverage of 'European Forest Dieback/Decline' which, interestingly, is covered as a Class III relationship and the inclusion of a photograph (Fig. 12.10) of the CEGB's forest fumigation at Liphook Forest in the UK. Red spruce decline in North America, like European declines, is covered as a regional response in section III and the case study of Class II
Book reviews
of fertilizers and pesticides but there seems to be a strong influence from climate as well. Other chapters deal with other types of bloom, notably red tides caused by dinoflagellates and the bloom of the prymnesiophycean flagellate, Chrysochromulina polylepsis, which was such a nuisance in the Kattegat-Skagerrak area in 1988, as well as more general aspects. The situation seems to have been best summed up by L. B. Slobodkin. Referring back to G. E. Hutchinson's 'paradox of the plankton', which refers to the circumstance that, in general, numerous phytoplankton species are found to co-exist although ecological theory would lead us to expect that interspecific competition within a homegeneous body of water would result in the survival of only one, he points out that the blooms are the 'null case' of the paradox. Normally, the time scale of environmental change in open waters is shorter than that required for the process of competitive exclusion but if a water mass favourable to phytoplankton growth maintains its integrity for long enough for an initial inoculum to reach bloom proportions a unialgal population results. This leads to the thought that hydrography is the crucial factor for development of blooms, but, curiously, not a great deal is said about this. The work of the Plymouth group on the red tide associated with the shallow sea tidal mixing front off Ushant is not discussed. The view which emerged from the conference on which this book is based, that dramatic phytoplankton blooms result from the convergence of perhaps subtle but long-term anthropogenic and eutrophication effects with aperiodic environmental conditions, seems to put the emphasis on secondary factors. However, although no very clear explanation of 'novel' blooms is arrived at, there is much in this book--the chapter by J. McN. Sieburth and P. W. Johnson surveying the composition of the picoplankton, for example--which will be of value to biological oceanographers and phycologists as well as to those who have to cope with the untoward effects of blooms. G. E. Fogg
Forest Decline and Air Pollution: A Study of Spruce (Picea abies) on Acid Soils. Edited by E. D. Schulze, O. L. Lange & R. Oren. (Ecological Studies, Vol. 77, edited by W. D. Billings, F. Golley, O. L. Lange, J. S. Olson & H. Remmert). Springer-Verlag, Berlin, 1989. 475 pp. Price: DM298 (hardback).
This volume is an extraordinarily valuable addition to the Ecological Studies series and to the literature on forest ecosystems. The work conducted by the Bavarian Forest Toxicology Research Group between 1982 and 1988 in the Fichtelgebirge Forest (northwest Baria, FRG) is described in a series
Book reviews
93
of detailed papers and a final synthesis is presented. Since the initial observations of widespread forest decline in central Europe in the late 1970s, it has become increasingly clear that there has been, and continues to be, a range of species and regionally specific forest declines, rather than a single and irreversible 'Waldsterben' as was once feared. The work conducted in the Fichtelgebirge has been focused on two 30-year-old Picea abies stands on similar base rock and experiencing similar climatic conditions. At one of these stands (Wiilfersreuth) the trees are healthy while at the other (Oberwarmensteinach) the trees show type 1 decline of P. abies (Needle yellowing and Mg deficiency). As this work has gradually been presented to the scientific community at conferences and in the journals, there has been a recognition of the value of these intensive stand studies and a growing understanding of the complex decline sequence which has occurred in the Fichtelgebirge. In the present volume three introductory papers cover the chronological development of Forest Decline in the F R G and the evolution of the research in The Bavarian Forest, the vegetation of the Fichtelgebirge and, of considerable interest, a discussion of the potential and limitations of field studies of the type being described. The book then has five main Parts as follows: (1) air pollution: transport and deposition, (2) the role of fungi, microorganisms and soil animals, (3) direct effects of pollutants on aboveground plants, (4) soil responses to acid rain and associated effects on plants, and (5) processes leading to forest decline: a synthesis. The fourth part on soil responses is the longest, it being made up of nine papers. The various aspects are tied together well and reflect the development of the 'nutrient disharmony' as a broad unifying concept or 'composition of hypotheses' within which forest declines can be considered. The nutritional principles and the schematic model of elemental fluxes, compartments and regulating parameters in a forest ecosystem under the influence of air pollution (pictured on the front cover) have a much broader relevance than would be anticipated from a 'two-site' study, and benefit from the intensive studies of different species and forest areas which have been conducted by other groups over the same period. As a consequence of the intensive studies, including those described here, our understanding of forest ecosystems and their responses to stress has advanced considerably over the last 10 years. In the case of the Fichtelgebirge, it is fascinating to see how initial vague notions on the importance of the direct effects of SO 2, and possibly of O 3, led to work on decline symptoms (yellowing and needle loss), photosynthesis and elemental leaching from the canopy and then on to sulphate, nitrate and ammonia inputs and effects on soils and soil processes. These studies have provided an appreciation of the significance of nitrogen inputs, soil acidification and Ca/A1 ratios, and of the balance between
94
Book reviews
nitrogen, magnesium and other nutrients (Ca, K and P) in forest canopies. It is suggested that declines are associated with disharmony between uptake and demand for nutrients. The authors do not claim that all the answers have been found and give some useful pointers for current priorities. The book draws together the various Fichtelgebirge studies very well and puts them in context against the associated hypotheses which have been developed by T. Ingestad, B. Ulrich and others over the same period.
Peter Freer-Smith
Air Pollution and Forests Interaction Between Air Contaminants and Forest Ecosystems. (2nd Edition) By William H. Smith. Springer-Verlag, Berlin, 1990. 618 pp. Price: DM198.00. In 1972 W. H. Smith was asked to review the relationship between air pollution and forests for the American Association for the Advancement of Science and his efforts resulted in the publication of the first edition of 'Air Pollution and Forests..." in 1981. History has judged that this large task was fulfilled skilfully with the book becoming well known and much referred to. Part of the success of the first edition can be attributed to the structure within which the review was undertaken. This was to consider pollutant and forest interactions in three classes: Class I relationships by which low doses result in forests acting as sources and sinks, and experiencing beneficial effects or being unaffected; Class H relationships which occur when intermediate doses are experienced and may give subtle adverse effects on nutrition, metabolism, and entomological and pathological interactions; and Class III relationships when high doses result in acute damage and tree mortality. Each of these classes make up a section of the book and the sections have between two and nine chapters. The second edition adopts the same structure but with a better introduction and with the addition of a fourth section on 'Global Atmospheric Stress and Forest Risk Assessment'. This has chapters on climate change and on the role of air quality in influencing forest helath. The new edition has additional chapters within the original three sections; the review is still of temperate forests only (40 ° to 60°N) and is based almost entirely on North American work. Exceptions to this are the brief coverage of 'European Forest Dieback/Decline' which, interestingly, is covered as a Class III relationship and the inclusion of a photograph (Fig. 12.10) of the CEGB's forest fumigation at Liphook Forest in the UK. Red spruce decline in North America, like European declines, is covered as a regional response in section III and the case study of Class II