Comparison of growth habits under various light conditions between two climax species, Castanopsis sieboldii and Castanopsis cuspidata, with special reference to their shade tolerance

Abstract

Two experiments were conducted to examine the difference in shade tolerance between two climax species, Castanopsis sieboldii and Castanopsis cuspidata, in Aichi Prefecture in the warm‐temperate climate of Japan. In the growth experiment, the seedlings of the two species were raised under five light conditions, 100%, 30%, 10%, 3% and 1% relative light intensity (RLI). The growth of C. sieboldii highly exceeded that of C. cuspidata, particularly under higher light conditions. In the heavy shading experiment, the seedlings of the two species were grown under three light conditions (0, 0.15 and 0.3% RLI). While all seedlings of C. sieboldii died within 2 years under 0.15 and 0.3% RLI, about half of the seedlings of C. cuspidata survived more than 2 years under 0.15% RLI, and about 70% survived more than 4 years under 0.3% RLI. It was concluded that C. cuspidata was more shade tolerant than C. sieboldii, and the possibility that C. sieboldii might be more tolerant of the drought stress than C. cuspidata was discussed.