Applied forest tree improvement

152 limited practical value {e.g., the chevron burn and sprinkler system discussion on pp. 237--238). The detail, so obvious in previous chapters, was replaced by meaningless generalities in all too m a n y instances. Also missing in this chapter was coverage of m a n y topics of high current interest (e.g., a comparison of the helitorch and aerial ignition systems). The intentional use of fire in fire adopted ecosystems is downplayed, thereby limiting the reader's exposure to the potential benefits of this tool so widely accepted and used by resource managers. Some r e d u n d a n c y was also noted between chapters in Volume 2. For example, explosives were discussed on p. 111 and again on pp. 150--152; hazard reduction on pp. 9 0 - 9 3 , and again on pp. 210--212 including the same figure (Fig. 4.8 on p. 92 and Fig. 9.5 on p. 225). A major shortcoming was the manner in which information is cited. I found much new material (at least to me) of interest but was continually frustrated in m y a t t e m p t to find the source of information. At the same time, I often noted references to material I would consider c o m m o n knowledge. In general I f o u n d the criteria ~.sed in deciding what or who to reference very puzzling; in a n u m b e r of cases it appeared that a previous summary was used, and that a u t h o r was given credit rather than the original researcher. In spite of these limitations, the book has much to offer both the expert and the interested layman. It treats wildland fire from a worldwide perspective and as such gives a good foundation to build upon. Although its high cost may be prohibitive to some, I for one am finding it a useful addition to my library. DALE D. WADE Southern Forest Fire Laboratory P.O. Box 182A Dry Branch, GA 31020, U.S.A.

FOREST TREE IMPROVEMENT A p p l i e d F o r e s t Tree I m p r o v e m e n t . B.J. Zobel and J.T. Talbert. Wiley, New

York, NY, 1984. 528 pp., £30.55, ISBN 0-471-09682-2. Recognition of the importance of tree improvement to any commercial forestry enterprise has resulted in the establishment of improvement programmes in most timber-growing countries of the world. The principles on which these programmes are based are those which have been successfully applied to agricultural crop plants, and tree breeders have used techniques developed by agriculturalists to achieve substantial gains in volume, form and adaptability in the first generations of selection. However, forestry and agriculture operate on different time scales and with rather different biological material, and m e t h o d s of tree improvement are n o t always those of tradi-

153 tional crop breeding. The publication of this book at a time of increasing interest in tree improvement is therefore to be welcomed. The authors of Applied Forest Tree Improvement have an impressive a m o u n t of practical experience between them, and the senior author is a world authority on forest tree breeding. Their objective in writing the book was to summarize the information needed to run an efficient tree improvem e n t programme. In this they have succeeded, and filled a rather obvious gap in the forestry literature. The book has 16 chapters, the first 4 of which are concerned with general concepts of tree improvement and the remaining 12 with specific topics, ranging from selection in natural stands through seed orchard management to the use of vegetative propagation and hybridisation. There are chapters on the possibilities of enhancing w o o d quality through breeding, gene conservation and the economics o f tree improvement, and the final chapter is a succinct account of the practical application of the principles and methods described earlier in the book to the setting up of improvement programmes. Selected references are listed at the end of each chapter, and there is a useful section on the more general literature available as books, periodicals and proceedings. Tree improvement should n o t be equated with tree breeding. It is only when the improved genetic material produced by tree breeders is grown under appropriate management regimes t h a t its full potential is realised, and the importance of this relationship between silviculture and genetics is emphasised t h r o u g h o u t the book. Another recurring theme is the need to maintain a wide genetic base in a long term breeding programme, and there is a well balanced discussion of the implications of the reduction in genetic variation which would result from the use of clonal plantations on a commercial scale. As might be expected in a t e x t on an applied subject, it is made quite clear that all tree improvement must be economically justifiable, but due attention is paid to topics which, for various reasons, cannot y e t be subjected to economic analysis. These include the relatively new techniques o f tissue culture and the role of tree improvement in meeting possible future forestry needs (pollution resistance in industrialised nations, drought resistance in arid areas where fuelwood and fodder species need to be planted on a massive scale). Many of the examples which are given of the successes (and failures) of tree improvement are from North Americ, but work in other parts of the world, particularly the tropics, is also decribed. This adds to the general interest of the book, which was written with three different audiences in mind; students, those directly involved in tree improvement and forest managers. Despite the claim of the authors that no formal training in genetics or statistics is necessary for a proper appreciation of their book, readers w i t h o u t this background will probably find the concepts covered in the early chapters difficult to follow, and in this respect the deliberate omission of a glossary is unhelpful and puzzling. A number of typographical errors un-

154 fortunately escaped notice in the proof-reading process, which is merely irritating -- or amusing -- in the text but more serious when they occur in equations and a table in the chapter on genetic testing. These errors will doubtless be corrected in future editions for which I confidently predict that there will be a continuing demand. CHRISTINE CAHALAN Department of Forestry and Wood Science University College of North Wales Bangor, Gwynedd LL5 7 2UW, Great Britain

LOB TREES IN THE WILDERNESS L o b Trees in the Wilderness. Clifford Ahlgren and Isabel Ahlgren. University

of Minnesota Press, Minneapolis, MN, 1984. 218 pp., US $12.95 {paperback). ISBN 0-8166-1264-5. Trees have been used by man as boundary markers and guide posts for thousands of years. The lob trees of the title were the tall pine or spruce selected by the voyageurs as guideposts in the uncharted wilderness of lakes, streams, forests and muskegs of the Minnesota--Ontario border. Branches were lopped off parts of the crown, leaving the middle bare with a t u f t of branches above and below, to make the tree more obvious. This book is in fact an ecological history of human activity in the Q u e t i c o Superior wilderness areas, and especially the Boundary Waters Canoe Area (BWCA), which covers over one million acres. The book is arranged in nine chapters, each named after a native species as a symbolic lob tree. Well illustrated and compulsive reading, these chapters cover the flora, the effect of forest fire, the pre-settlement forests, the early inhabitants (Indians, furtrading voyageurs, early settlers), the pine logging period, the pulpwood logging period, recreation and preservation. The final chapter discusses at some length the concept of wilderness, the complex interrelationships of wilderness and people, and the management of both. Since the passing of the Wilderness Act (1964), the BWCA has been part of the wilderness preservation system, y e t one with over one million visitordays recorded in 1975 -- the authors argue that "an area is wilderness if it is perceived as such", and hope that we can "live, study, use, and be part of this wilderness in a way that restores both our h u m a n i t y and the forest". Strangely, in this excellent book, the authors fail to explain the origin of the curious term lob trees. Readers might assume that lob here is a corruption of lop, but this is n o t the case: Wright's English Dialect D i c t i o n a r y tells us that one old meaning of lob is " t h e part of a tree where is first divides into branches". WILLIAMLINNARD Welsh Folk Museum St. Fagans, Cardiff, CF5 6XB Great Britain