As forests decline in temperate and tropical climates, highly-developed countries and those striving for greater economic and social benefits are beginning to utilize marginal forests of high-latitude and mountainous regions for resources to satisfy human needs. The benefits of marginal forests range from purely aesthetic to providing resources for producing many goods and services demanded by a growing world population. Increased demands for forest resources and amenities and recent warming of high latitude climates have generated interest in reforestation and afforestation of marginal habitats in cold regions. Afforestation of treeless landscapes improves the environment for human habitation and provides for land use and economic prosperity. Trees are frequently planted in cold climates to rehabilitate denuded sites, for the amenity of homes and villages, and for wind shelter, recreation, agroforestry, and industrial uses. In addition, forests in cold climates reduce the albedo of the earth's surface in winter, and in summer they are small but significant long-lived sinks for atmospheric carbon dioxide. Finally, growth and reproductive success of forests at their geographic limits are sensitive indices of climatic change. As efforts to adapt forests to cold climates increase, however, new afforestation problems arise and old ones intensify. Austral, northern, and altitudinal tree limits are determined by many different factors. Current hypotheses for high-latitude tree limits are based on low growing-season temperatures that inhibit plant development and reproduction.

''Required reading for forest scientists.'' -Northeastern Naturalist

This book will provide a complete overview of an alpine ecosystem, based on the long-term research conducted at the Niwot Ridge LTER. There is, at present, no general book on alpine ecology. The alpine ecosystem features conditions near the limits of biological existence, and is a useful laboratory for asking more general ecological questions, because it offers large environmental change over relatively short distances. Factors such as macroclimate, microclimate, soil conditions, biota, and various biological factors change on differing scales, allowing insight into the relative contributions of the different factors on ecological outcomes.

Geographic Variation in Forest Trees is the first book to examine this subject from a world-wide perspective. The author discusses population genetic theory and genetic systems of native North American tree species as they interact with environments in the major climatic regions in the world. He then demonstrates how this knowledge is used to guide seed zoning and seed transfer in silviculture, basing much of his discussion on models developed in Scandinavia and North America. In the final chapter, the author addresses the issue of genetic conservation -- a subject of great concern in the face of accelerated forest destruction, industrial pollution, and climatic change. This comprehensive, well-researched book makes a significant contribution to the knowledge of one of our most important renewable natural resources.