Variation in periodic diameter increment of trees in an old sugi (Cryptomeria japonica D. Don) plantation at the base of Mt. Iwate

摘要

We investigated the variation in the diameter increment of lower stratum trees in adense plantation of old sugi with respect to the initial tree size and the competitive interaction among neighboring trees. The base diameter and two competitive interaction indices were used in stepwise multiple regression procedures to model the periodic diameter increment of individual trees. All independent variables were within a level of significance, and they were accepted in the regression model. It was concluded that the diameter increment of lower stratum trees in old sugi plantations was positively and negatively correlated to the initial diameter and the competitive interaction, respectively.