© 1989 Heron Publishing—Victoria, Canada
Solar equivalent leaf area: an efficient biometrical parameter of individual leaves, trees and stands
J. Cermák
Institute of Forest Ecology, University of Agriculture, 64400 Brno, Sobesice, Czechoslovakia / Received May 17, 1988
Summary
The solar equivalent leaf area (As), a simply and easily determined biometrical parameter of leaves, trees and stands, was derived theoretically. The parameter
is defined as projected leaf area weighted for the time integral of irradiance at a given location in the canopy relative
to that of fully irradiated leaves at the top of the canopy. The efficiency of As as a basis for estimating stand-area transpiration of a mature oak (Quercus robur L.) forest from measurements of transpiration by individual trees was compared with that of other stand and tree characteristics.
Stand transpiration estimates based on As were more precise and less prone to systematic error than estimates based on basal area, timber volume, projected tree crown
area, projected leaf area, or leaf dry mass. Solar equivalent leaf area reflects both the amount and the physiological properties
of leaves and can be used as a measure of tree size and functional capacity. It can be calculated from ordinary forest inventory
data on trees and stands, adjusted according to simple phyllometric data. It appears to have wide application in ecological
and forestry studies for relating the physiological characteristics of individual leaves to those of entire trees or stands.
