Abstract
Cercidiphyllum japonicum has high sprouting ability leading to multi-stem growth form, which may enable successful coppicing after logging. To evaluate multi-stem patterns, we measured stem sizes of C. japonicum trees in a broadleaf forest in central Hokkaido, where selective logging has been conducted, and obtained stem diversity (the inverse Simpson’s index) in terms of their basal area proportions. In a zone (17.8 ha) where all C. japonicum (71 intact and 11 logged) trees were monitored, 33 (40%) trees had multiple stems. In total 123 trees monitored in the zone and sampled along a route (3.4 km), the stem diversity increased in logged trees and in trees reaching forest canopy as their size increased. In 40 logged trees of the 123 trees, we did not detect any factors, including logging conditions (stump size and age), that affected the stem diversity. These findings suggest that logging facilitates sprouting irrespective of environmental conditions, whereas bright-light conditions are responsible for sprouting of intact trees.
