Abstract:To describe the differentiation characteristics of a 50-year-established Metasequoia glyptostroboides plantation, we examined its size structure, spatial pattern and growth process. Small-size individuals accounted for the majority (>50.4%). To some extent, self-thinning had occurred, as a result of high differentiation of tree height and volume. Tree-status classification structure based on TSTRAT stratification algorithm demonstrated that co-dominant trees represented an overwhelming portion (45.7%) and formed the general canopy of the stand. Value of competition index was the lowest for dominant class, successively followed by co-dominant, intermediate and suppressed class. Gini coefficient value of each class was basically inferior to that of the whole stand. Both in absolute and relative rates, dominant trees grew faster than standard trees before stand maturation. Furthermore, fast-growth stage of DBH for the former lasted longer than that for the latter. At stand level, DBH growth was more seriously restricted than height growth. The general pattern of all stems remained uniform, the same as onset of the plantation. However, occurrence of divergent tree-classes was spatially heterogeneous, with dominant and suppressed class being aggregated, intermediate and dead class randomly scattered, and co-dominant class intervened between randomness and aggregation. Our results suggested that differentiation of tree population was reflected not only in size inequality but also in heterogeneity of spatial configuration. Current stand structure might attribute to intraspecific competition induced by high density.
