XVI International Botanical Congess

Origin and fate of individual gaps in a lowland tropical rain forest was analyzed in Pasoh Forest Reserve in Peninsular Malaysia with aerial pictures. Areas whose canopy height was below 15 m were regarded as canopy gaps and all the individual gaps were followed from May 1995 to February 1997. Fate of the gaps was remarkably size dependent. Most of small gaps closed within two years, while some larger gaps were fragmented. Origin of the gaps was also size dependent. Nearly half of the gaps were found to have newly occurred during the two years, though they were mostly in the smallest size class. The contribution to the increase of total gap area by the enlarging existing gaps was compatible to that by the newly occurred gaps.