Relationship between Growths of Three Subcanopy Species, Camellia japonica , Ilex integra and Ilex latifolia and Two Effect Factors, Initial DBH and Competitive Environments of Object Trees in an Urban Forest

We measured all woody stems with equal to or larger than 10 cm DBH in the whole area of Tadasu-No-Mori forest, a large-scale mature urban forest in Kyoto city in 2002 and 2010. We examined relationship between basal area increments of three main evergreen broadleaved subcanopy species, Camellia japonica, Ilex integra and Ilex latifolia, and two effect factors, initial size and competitive environments of object trees. Although I. integra and I. latifolia belong to the same genus, these species showed different growth characteristics each other. There was a positive correlation between log-transformed basal area increments of I. integra and their initial DBH. The ratio between the height of object tree and those of the neighbors, and horizontal distances to the neighbors had strongly negative effects on the growths of I. latifolia and C. japonica. I. latifolia and C. japonica had been affected by competitive trees stood within 8 m and 13 m radius from object ones respectively. The proportion of the DBH of object tree to those of competitors, and distances to the competitors had influence on the growths of I. integra. Initial DBH and the best competition index could explain a large proportion of log-transformed basal increments of I. integra (54%).