THE ROLE OF PHYSIOLOGY IN FORESTRY

Although a great deal of information concerning the physiology of trees has been accumulated, physiology has made a smaller contribution to forestry than it should. This is partly because of a lack of communication between field and laboratory workers and partly because of a lack of a general understanding of the role of physiology in forestry. The physiological processes of trees are the machinery through which the genetic potential and the environment operate to determine the quantity and quality of growth. Actual wood production usually is far below the genetic and physiological potential because important physiological processes are often inhibited by environmental stresses such as drought, mineral deficiencies, unfavorable temperatures, and air pollution. The most useful contribution that physiologists can make to forestry is to determine which physiological processes are inhibited by particular stresses and suggest to tree breeders what characteristics will minimize the inhibitory effects of these stresses. Cooperative screening studies with geneticists to identify differences among families and provenances that result in differences in stress tolerance should be very productive. Perhaps as the cost of establishing forest stands increases, more attention will be paid to the selection of genotypes with physiological characteristics best suited to local environments. Because of the complex interactions among stresses there is need for long-term interdisciplinary research programs in which soil scientists, meteorologists, and physiologists cooperate with foresters and forest geneticists in identifying stresses and their inhibitory effects on forest productivity. Because of the increasing specialization in science there also is great need for broadly trained generalists who can understand research in several fields, identify important contributions, and show their significance to investigators in other fields.