落葉広葉樹林におけるケヤマハンノキの開葉・落葉および葉の寿命

抄録

Observations were made on bud break, shoot elongation, leaf development and defoliation of alder (Alnus hirsuta TURCZ.) in a deciduous hardwood forest stand in Hokkaido. Leaf emergence started in early May. The mean number of leaves attached to a shoot increased progressively until late June or early July when it reached a maximum, about 5 leaves a shoot, and then decreased to zero in early November. Leaf defoliation increased during late June and July, and again after September. Mean longevities of leaves were 90 and 97 days. The mean longevities of the first and the second leaves were shorter than the other leaves. The first, the second and the third leaves were classified as early leaves from the morphological features. These three leaves were assumed to be different functionally also from the other leaves.