ABOVEGROUND MORPHOLOGY OF SHADE-TOLERANT CASTANOPSIS-FARGESII SAPLINGS IN RESPONSE TO LIGHT ENVIRONMENT

Branching pattern and intensity, aboveground biomass partitioning, and leaf display in response to light environment were studied in saplings of the shade-tolerant broad-leaved evergreen tree Castanopsis fargesii. Relative light exposures corresponded with those in forest gaps and clearings: 18%, 33%, 55%, and 100% full sunlight. At 18% full sunlight saplings had comparatively long main stems and long, sparsely bifurcating first-order lateral axes (as counted centrifugally). In more exposed environments saplings developed shorter first-order lateral axes that supported larger numbers of higher order axes of greater total length and weight. These saplings had relatively small leaves in high densities. The differences in aboveground morphology were partly due to variability in overall plant size and were partly a direct effect of light environment. The different crown shapes and foliage densities were considered adaptive in the different light environments. The favorable growth and morphological responses of the saplings to high light environments indicate that C. fargesii is a competitive species in large gaps and clearings.