XVI International Botanical Congess

To understand how biotic and environmental factors interact to influence tree seedling recruitment during secondary succession, we conducted a factorial experiment in 20 yr. old forest stands. Ten experimental plots (40 x 40m) were established, in 5 plots trees were cut to create a large (330-470 m2) gap and in 5 plots the canopy remained intact. Within each plot, 5 blocks were established in which 3 levels of litter cover (bi-monthly addition, removal, control) were applied within each of 2 levels of understudy vegetation density (bi-monthly clipping, control). Seedling recruitment, growth and mortality were monitored bi-monthly for a years. Experimental gap treatments markedly increased the abundance of recruited tree seedlings. Clipping treatments reduced mortality of tree seedlings only in litter control and removal quadrats. Tree seedling recruitment was reduced by litter addition in experimental gaps, and by litter removal in non-gap plots. The overriding overall effect of experimental gaps suggests that selective logging could enhance regeneration of the dominant canopy tree species in these secondary forests.