Mortality and recruitment of trees in a secondary montane rain forest in southeastern Brazil.

Abstract

Mortality and recruitment rates were obtained for tree species over a 5.6 year period in a 1-ha fragment of secondary montane rain forest in Southeastern Brazil. All plants with a diameter at breast height (dbh) > or = 8 cm were sampled in 1989-1990 and 1995. There was an increase from 90 to 96 species, and 669 ind./ha to 749 ind./ha over the period. The mortality rate of 1.67%/yr was similar to findings for other forests, while recruitment of 3.46%/yr was the highest rate reported. Both mortality and recruitment were significantly higher in the smaller dbh classes. Recruitment was higher among rare species, and the relatively slow-growing species had significantly higher mortality rates. Differences between species dynamics were marked. Species with high values of lambda were mainly early successional and understorey trees but some understorey species also suffered a marked population decline. The classification system of species in response to light which divides understorey species into "partial shade-bearers" and "shade-bearers" groups showed to be the most suitable to the obtained results. The results suggest that this forest is undergoing a process of recovery from past disturbance.