LEAF WEIGHT PER AREA AND LEAF SIZE OF 85 ESTONIAN WOODY SPECIES IN RELATION TO SHADE TOLERANCE AND LIGHT AVAILABILITY

Leaf weight per area (LWA) and leaf size were examined in 85 species of woody plants representing 83% of Estonian native flora. Average values of 68.6 g m(-2) for LWA and 6.62 cm(2) for leaf size were estimated for the medium light availability. Mean LWA values can be used to correct for the bias in estimating foliage functional properties in forest stand models and for converting leaf biomass into foliage area. LWA increased with relative light availability (1 minus stand canopy cover) and species light demand, indicating that LWA was higher at the same light availability for more intolerant species. Leaf size is a canopy parameter that should be considered when canopy radiative balance and distribution of solar radiation is of interest. Mean leaf size was not so closely related to light availability as LWA, decreasing with species light demand and increasing with total plant height. Variation in leaf size is discussed in terms of species shade tolerance and height growth.