Leaf Area of Mature Northwestern Coniferous Forests: Relation to Site Water Balance

Abstract
Leaf area of nature coniferous forest communities of western Oregon appears to be related primarily to site H2O balance rather than characteristics of tree species composing the community. Leaf areas were determined for stands in communities ranked along measured gradients of precipitation and evaporative potential. Nine coniferous and 1 deciduous tree species were found in the various stands along these gradients. Leaf areas of these stands were linearly correlated with a simple site H2O balance index computed from measurements of growing season precipitation, open pan evaporation, and estimates of soil H2O storage. Species composition had no apparent influence on the relation between community leaf area and site H2O balance.