摘要
Based on investigation of 53 gaps and 25 quadrats (15m×15m each) of non-gap closed stand in an old-growth tropical montane rain forest of Hainan Island, China, canopy disturbance regimes and gap regeneration were studied. Gaps were elliptical in horizontal form, the ratio of long axis /short axis was about 1.4. Percentage of expanded gaps (EG) and canopy gaps (CG) area in the landscape were 53.5% and 25.2% respectively. EG ranged from 31.4 m2 to 488.2m2 and CG/rom 14.9m2 to 354.2m2, their average sizes ...
Based on investigation of 53 gaps and 25 quadrats (15m×15m each) of non-gap closed stand in an old-growth tropical montane rain forest of Hainan Island, China, canopy disturbance regimes and gap regeneration were studied, Gaps were elliptical in horizontal form, the ratio of long axis /short axis was about 1.4. Percentage of expanded gaps (EG) and canopy gaps (CG) area in the landscape were 53.5% and 25.2% respectively. EG ranged from 31.4 m2 to 488.2m2 and CG from 14.9m2 to 354.2m2, their average sizes were about 160 m2 and 80m2 respectively. Natural disturbance frequency for canopy gaps was estimated about 0.63%·y-1. Most gaps were formed within 30 years before 1997 by one to four gap-makers, the majority by two gap makers. The quantitative characteristics of tree species were different in gaps and in non-gap stands. 158 tree species in the forest were classified into eight groups according to their difference in orders of importance values in gaps and non-gap stands. Most of the tree species had their regeneration peaks at the gap sizes of 60-120 m2. The relationships between regeneration density and gap developmental stages had two forms, the unimodal and bimodal. Tree species diversity changed unimodally with gap developmental stages, but no obvious relations were found between the tree species diversity and gap size.
