Canopy dynamics in a tropical Atlantic forest mosaic in southeastern Brazil

Abstract

The influence of seasonality on leaf production and canopy dynamics was evaluated in four areas in the Rio Doce State Park—RDSP, which is part of the Atlantic Forest Biosphere Reserve in Marlieria city, Minas Gerais State, southeastern Brazil. Leaf production was determined during a period of two years (2007 I and 2008 II) and on a monthly basis (25 collectors of 0.25 m2) to determine dry mass and specific leaf area at four different areas (Preta, Central, Garapa, and Anibal). Leaf area index of canopy values (LAI-canopy) was determined using hemispheric canopy photographs in October 2008 and March 2009. Specific leaf area of the leaf litter samples (LAI-SLA) was calculated during November (2008) and March (2009). Leaf production followed a seasonal rhythm, with higher cumulative production between the middle of the dry season and beginning of the rainy season (August to November). The LAI-canopy values did not have significant variations between the four areas evaluated; however, significant difference between seasons was observed in the Anibal and Central areas. The LAI-SLA was higher in Anibal while Preta, Central, and Garapa presented similar values. Our results evidenced the possible influence of the leaf fraction on canopy dynamics and LAI and revealed the rapid leaf renewal characteristics of seasonal semideciduous forests. We observed spatial heterogeneity of semideciduous forests maintaining a partial canopy cover even in the season with the greatest leaf fall. This explains to the absence of any significant correlation between leaf production and LAI-canopy as observed in the present study.