A 23-year-old Sugi stand planted in clumps was surveyed. 1) Because of the wide clump spacing, plots A and C were not closed by tree crowns. However, plot B with narrow clump spacing was completely closed. 2) A large number of trees had died due to oppression by adjacent trees over the previous ten years and the difference in survival rates increased among the clumps. An especially large number of trees had died in the clumps of six trees. Almost the whole clump of six trees had disappeared from plot B with narrow clump spacing. 3) The greater the number of trees per clump, the smaller the individual mean became. The difference between the individual mean for the clumps of single trees and that for the clumps of six trees was increased. Even if the number of trees per clump increased the basal area per clump showed a tendency to reach a ceiling, but this trend was not observed in plot B with narrow clump spacing. 4) The greater the number of trees per clump, the smaller the largest tree in the clump became. It is considered that this phenomenon demonstrates intraspecific competition. 5) The greater the number of trees per clump, the more steady the individual ranking was fixed. The difference between the superior and inferior trees was obvious in the clumps of several trees.

The growth of new culms and the seasonal changes of photosynthetic ability were investigated. 1) The new culm of Suzutake begins to sprout when the daily mean soil temper­ ature at the depth of 10 cm go up to about 10'C and finishes its elongation within two months. 2) After the completion of culm-elongation, the new leaf begins to unfold and finish it completely by ten days or more. The unfolding of all leaves have been completed within 30~50 days following the first-leaf appearance. 3) The phtosynthetic ability of new leaves is higher than in any old leaf. 4) As the optimum condition in photosynthesis, temperature should be about 20'C and light intensity, 30 Idux and more. 5) Although the photosynthetic ability of a new leaf continued to increase until late in the first growing season, it decreases rapidly at a temperature below OT. The decreased photosynthetic ability hardly recovers. 6) It became evident that the photosynthetic ability of shade leaf is higher than that of a sun leaf in low light intensity and Suzutake was found to be a shade-enduring plant.