Reestabelecimento da vegetação no sub-bosque de plantios de pinus: diversidade arbóreo-arbustiva e relações ambientais

Abstract

This study encompasses the natural regeneration of a tree-shrub community in three Pinus sp. stands, one natural area (cerrado sensu stricto) and the effects of environmental and biophysical variables of canopy coverage, litter thickness, basal area of surrounding vegetation and distance from remaining natural fragment (for Pinus sp. stands only) in the distribution of regenerating species. We set 20 plots of two distinct size classes (100m² and 4m²) in each of the four areas for this purpose, in which all treeshrub regenerating species were assessed. Afterwards, a Canonical Correspondence Analysis (CCA) was performed for the four areas. Significant values were found for two areas, in which the variables of distance from fragment, basal area and litter thickness had shown a strong effect in tree-shrub regeneration in the corresponding areas. The species Siparuna guianensis, Miconia albicans, Xylopia aromatica, Sclerolobium paniculatum, Casearia sylvestris and Pinus sp. were the most important ones in the four study areas. We also analyzed the dipersal syndromes in each of the four areas, that had shown a very similar pattern: The prevalence of zoochory in all of the four study areas. The three Pinus sp. stands studied had shown a quite heterogeneous regeneration, with the number of regenerating species ranging from 18 to 42 in their overstories. In the natural area (cerrado s.s) we found 90 regenerating species though, the corresponding data of species richness, density and species frequency for the three Pinus sp. stands analyzed were similar to those found in disturbed or degraded cerrado areas in Uberlândia municipality and nearby. The data assessed in this study provides useful information on the comprehension of natural regeneration process beneath commercial plantations in Triângulo Mineiro region. In the last part of this paper we present some guidelines for future studies and forestry implications based on our data.