Abstract
We investigated the mean crown lengths of Japanese cedar trees in 12 overcrowded mature plantations. In pooling the data for unthinned young and overcrowded mature plantations, the mean crown length of Japanese cedar trees in each plantation was positively correlated with mean upper tree height in each plantation. However, the average mean crown length of trees in overcrowded mature plantations was 5.9 m, which was only slightly greater than that of trees in unthinned young plantations (5.4 m). Thus, if intensive thinning is not conducted, the crown lengths of mature trees will not steadily increase.
