TREE COMPONENT DEMOGRAPHY IN AN UPPER MONTANE MIXED OMBROPHILOUS FOREST UNDER CHRONIC ANTHROPOGENIC DISTURBANCES

ABSTRACT The objective of this study was to understand the dynamics of an Upper Montane Mixed Ombrophilous Forest in the municipality of Painel, Santa Catarina, Brazil, where low-level but chronic disturbances, such as extensive cattle grazing and exploitation of non-timber products, are common practices. In 2008, permanent plots were allocated and all tree species with circumference at breast height (CBH) equal to or greater than 15.7 cm were measured. A second survey was conducted in 2014 by the same methodology. Mortality, recruitment, and basal area gain and loss rates were then determined. The tree species were classified into regeneration guilds and proportion tests were conducted to verify the associations between dynamics patterns and guilds. The community has shown a 2.3%.year-1 average mortality rate, a 2.2%.year-1 average recruitment rate, a 3.0%.year-1 average basal area gain rate and a 1.8%.year-1 average basal area loss rate. Species number has decreased from 55 to 48. Regeneration guilds have shown different dynamics patterns, where the pioneers have shown the greatest mortality (19.9%) and recruitment (15.6%) proportion and reduced representativeness in shade-tolerant climax species. Therefore, floristic impoverishment and higher representativeness reduction of late species have been observed. We have concluded that despite disturbances do not result in structural deterioration, they have the potential to slow the succession process and cause a floristic homogenization in the area under study