Policy and practice in the management of tropical watersheds
How old is that tree?
Insect control in temperate forests
Genetic effects of air pollutants in forest tree populations
Environmental policy in china
H.C. Pereira. Policy and practice in the management of tropical watersheds. Boulder Colorado. USA Westview Press. 1989.
In this new book Sir Charles Pereira covers so many aspects of tropical watershed management, in so many countries, that the first impression is one of superficiality, combined with a suspicion that no one person could possibly possess this amount of first-hand knowledge. Further reading, however, reveals that most of what is written is personal, on-site experience; and the amount of ground covered has been made possible not by skating hastily over it, but by a welcome economical use of words. The result is an invaluable overview of tropical watershed management in theory and practice from someone who has been there and knows what he is talking about.
Policy and practice in the management of tropical watersheds is packed with examples, case histories, illustrations, results, and exact references to projects and programmes. Sir Charles's critical analysis is always constructive, and most, perhaps all, reference sources in the book will be proud of having been included and feel they have received fair treatment.
The author is at ease presenting information on local-level management, for example about a small-farmer-oriented tree-farming programme in Gujarat, India. He is equally clear and no less decisive on broader topics. Summarizing the outlook for population distribution and global rainfall, Pereira says, "The 3-year drought that afflicted the African continent in the mid-1980s raised speculations about a change in world climate. There are only 200 years of rainfall data continuous enough for statistical analysis. The two major analytical centers for meteorological data are at Bracknell in Britain and at Boulder, Colorado, in the USA. Scientists at both centers have studied the data and have found no evidence of general change in either the amount or reliability of rainfall.
A degraded watershed in Pakistan
Mankind is, however, achieving an effect similar to world climatic change by the vast disproportion between the population growth rates in the high latitudes and in the tropics. UN estimates show that, in addition to the world's present 5 billion people, by the end of the century there will be at least another billion who will need to be fed. Some 80 percent of these will be born in developing countries dependent on subsistence agriculture" and, further on, "The symptoms of excess population pressure are the misuse of land and the rural poverty that ensues. When this occurs in critical upper watersheds, the process of hydrology transmits the damage to more productive areas downstream. Remedial policies to address both the reduction of population growth rates and the increase of food production are essential and urgent."
The book makes highly recommended reading for watershed managers, who will benefit from the width of the author's experience, as well as planners, economists and decision-makers who wish to inform themselves about our accumulated knowledge in this field. Few can provide this information more clearly and completely than Sir Charles Pereira.
T. Michaelsen
Growth rings in tropical woods (special issue of the IAWA Bulletin 10(2): 95-174). P. Bass & R.E. Vetter eds. Leiden the Netherlands International Association of Wood Anatomists Rijksherbarium. 1989.
One important element in ensuring the conservation and wise use of tropical forests is an understanding of forest dynamics, and of radial increment rates and distribution of tree age classes within them. Examination of the tree rings formed in many tropical species with seasonality of rainfall can produce a wealth of information suitable for dating, age determination and increment studies.
This special issue of the IAWA Bulletin contains the proceedings of a session on age and growth-rate determination in tropical trees, convened during the All Division 5 IUFRO Conference in São Paolo, Brazil, in May 1988 Eight articles are included, covering studies undertaken in Argentina, Brazil, Central Amazonian inundation forests, Costa Rica, French Guiana, Guinean-Congolese Africa, Indonesia, Thailand (mangrove area) and Venezuela.
By counting the annual rings in the core sample, the age of the tree can be determined
Several methods are described whereby the annual growth rate and the age of the trees can be determined. These range from simple ring width analysis to radiocarbon analysis comparing the C14 level in the growth rings with the level in the air, which during the past 40 years has varied considerably from year to year owing to the more than 400 above-ground atomic bomb explosions of the 1950s and early 1960s. As every plant incorporates radiocarbon in the same concentration as that in the air, this allows precise age determination of the growth zone of any tree that grew between 1950 and the present.
Another method discussed in this work is cambial wounding. This method is particularly useful for determining the growth rhythm of trees without visible growth rings.
These proceedings are a very valuable addition to the still small but increasing body of information on the growth-rate and age distribution of tropical forests, thus enabling the establishment of more detailed growth and yield tables leading to better silvicultural treatments and management systems for these forest.
M. Løyche
Ecology and management of forest insects. M. R. Speight & D. Wainhouse. Oxford, UK, Clarendon Press. 1589. Illus., 374 pp.
According to the authors, the objective of this book is to bring together new material on the ecology of forest insects and recent advances in insect control", as opposed to providing a guide to forest insect biology and identification, a topic on which there are a number of recently published works.
Ecology and management of forest insects is oriented toward temperate forest ecosystems with particular emphasis on plantations. The examples died throughout the text are predominantly, European, although a number of North American approaches to forest insect management are also described.
The text is organized into ten chapters. The introduction, Chapter 1, discusses the renewable nature of forest resources and includes brief descriptions of the forests of North America' Europe and the USSR, and New Zealand and Australia. The temperate forests of Mexico and the austral regions of South America are not reviewed. Chapters 2, 3 and 4 describe, respectively, the forest as a habitat for insects, trees as a source of food for insects and the nature of forest pests. The subsequent chapters address various pest management tactics, including forest practices, plant resistance, biological control, insecticides and behaviour-modification chemicals. The final chapter, "Integrated pest management", brings the individual tactics discussed earlier into pest management systems. This chapter ends with five case histories of attempts to manage economically important insects: four set in Europe, and one in North America.
The book is written in an easy-to-read narrative style, is well organized and is illustrated with a wide selection of graphics and black-and-white photos of good quality.
As might be expected with a treatment of this breadth, the text contains some omissions and minor technical errors. For example, a table of introduced insects fails to note the recent introduction of me European wood wasp, Sirex noctillio, into parts of South America, the European pine shoot moth, Rhyacionia buoliana, into Chile or me pine engraver beetle, Ips calligraphus, into the Philippines. In addition, a discussion of thinning as an option to increase resistance to attack by the mountain pine beetle fails to differentiate between prescription for ponderosa and lodgepole pines. The discussion of the bacterium Bacillus thuringiensis is weak in the light of major control operations conducted against four species of defoliators in North America in recent years using this material. Finally, the section on survey and detection, monitoring and prediction in Chapter 10 makes no reference to aerial detection surveys, widely used in North America to monitor damage caused by bark beetles and defoliating insects.
Despite these flaws, the book presents a very readable treatment of a complex subject and should prove to be a valuable reference, particularly for European students of forest entomology and for pest management specialists working in Northern Hemisphere temperate forests.
W. M. Ciesla
F. Scholz, H.R. Gregorius & D. Rudin, eds. Heidelberg, Federal Republic of Germany, Springer-Verlag. 1989. 34 figs, 555 pp.
This book contains the papers presented at a joint meeting of the working panics on Genetic Aspects of Air Pollution, Population and Ecological Genetics and Biochemical Genetics of the International Union of Forestry Research Organizations (IUFRO), held in Grosshansdorf, Federal Republic of Germany in August 1987. To complement the presentations made in the meeting, papers have been added by the editors on general methods of analysis and interpretation of genetic research in forest ecosystems, and on related non-genetic research, bringing to 16 the total number of papers in the book.
The papers are arranged into four chapters, dealing respectively with methods of sampling and genetic analysis (2 papers); variation in response to pollutants (8); selection effects of pollutants (4); and preservation of genetic resources (4).
Air pollutants: what are their genetic effects on trees?
As is frequently the case in a collection of meeting papers, there is considerable variation in style, coverage and quality; some papers dealing with narrow aspects of the problem are not readily applicable outside the study area. However, the generally well produced abstracts and interesting "conclusions" sections will help guide the reader toward those papers of particular relevance. Furthermore, the general conclusions at the end of the book, which focus on gaps in present scientific knowledge, summarize the meeting in a nutshell and indicate to the reader the topics in which the discussions (and thus the papers) gave rise to interesting and thought-provoking debates.
Genetic effects of air pollutants in forest tree populations covers an aspect of environmental management that is of fundamental importance, but which often is not acknowledged as such, or is considered too abstract or specialized to merit general attention. This is due, at least partly, to the fact that information on the genetic effects of air pollutants has been found mainly in scattered articles published in scientific journals, or as popular, semi professional observations in the general media. The present book thus meets a manifest need by pulling together solid, scientific facts, both through the papers included in it and in their often extensive and up-to-date reference lists.
The book will be of interest to foresters and conservation biologists working in the conservation of natural ecosystems and the management of genetic resources; and to tree breeders involved in selection and improvement of trees and shrubs for production of goods and services. The concluding chapter and the papers that cover general principles and aspects for consideration in development strategies and research will also be of relevance to policy-makers and research directors, as well as to persons interested in environmental questions in general and atmospheric pollution and its consequences in particular.
Atmospheric pollution introduces a new selection criterion for the survival of species and ecosystems. Many of the genetic and ecological effects of this directional selection, the basis of which is discussed in the present book, will also be relevant when examining the (non-toxic and possibly more gradual) potential effects of another, rapidly emerging environmental factor: those of global, regional and local climate changes on forests and biodiversity.
C. Palmberg
Environmental policy in China. L. Ross Bloomington, Indiana University Press. 1988.
This book analyses Chinese environmental policy and assesses the efficacy of three alternative modes of policy implementation: planning and regulation; moral persuasion; and market forces. The author concludes that, despite major investments, bureaucratic planning and moral persuasion have largely failed to solve China's environmental problems, but that free-market approaches have the potential to enhance the environment as well as the economy.
Forestry for erosion control in China
The book also provides a study of the evolution of environmental policy in China, particularly in the decade following the third plenum of the Chinese Communist Party in December 1978, which saw the rise to power of the reformers under the leadership of Deng Xiaoping.
Of particular interest to readers of Unasylva will be the section on forestry policy. Here Ross provides a detailed description and analysis of the development of forestry policy and the growth of privatization in the forestry sector over the decade 1978-88.
When the Chinese Communist Party came to power in 1949 it immediately set out to establish government control over most forests as well as other natural resources. The Agrarian Reform Law of 1950 asserted state ownership of about 73 percent of the country's forest lands. Although private forestry survived for a short while, collectivism was clearly established by 1956.
In 1976, however, private forestry began a remarkable comeback in two forms: the allocation of private plots to forestry; and the development of the contract responsibility system. By 1985, 50 million households had control over 30 million ha of private plots, giving them responsibility for almost one-third of the land considered suitable for forestry.
An even larger area of private forestry is that accounted for under the contract responsibility system, under which collectives and some state farms retain full or part ownership of forest areas, but contract with households for their management. By 1986, over 40 million ha had come under the contract responsibility system. Land use is restricted to forestry, although intercropping is allowed. The type of forest to be planted must be approved by the cooperative, usually on the basis of the state plan, and the collective must approve all logging.
According to Ross, these semiprivate schemes were a major step in the right direction, but local officials and the state bureaucracies retained substantial power over contracts, permits, services and taxes and often used it to increase their own revenue at the expense of the private entrepreneurs. Ross argues in favour of increased infrastructure supports, investment capital, credit, higher producer prices and freer markets, better technical services and federal protection against local governments that threaten to tax the profits out of forestry.
In terms of water management and pollution control, Ross again concludes that the market approach is the best stimulus for efficient use of scarce resources. The key, he says, is not the level of economic activity but the degree of economic efficiency. In many instances, he suggests, approaches combining elements of bureaucratic enforcement and market forces are likely to emerge.
Social cooperation can also be enhanced, says Ross, by facilitating the development of free markets. Particularly needed in this regard", he says, "are the clarification and enforcement of property rights through stable and fair jurisprudence, as well as assistance in capital formation, market development and other functions already performed by governments in most countries on the Western Pacific rim."
"China's most essential need", says Ross, "is for further progress in the transition from the traditional pattern of rule by individual leaders setting personal examples... to a pattern combining the rule of law with government by representatives responsive to their constituents. Only in this fashion can citizens be expected to cooperate on behalf of social interests as well as their own."
While it may be too early to confirm his arguments, they are well presented and argued. The book is worthwhile reading for anyone concerned with the development of natural resource policy in general and particularly for those with a special interest in China.
R. Pardo
