Phytosociology of the shrub-arboreal stratum of the Ibura National Forest, Northeastern Brazil: are 35 years sufficient to promote the regeneration of a forest fragment?

portuguesEntre as varias aplicacoes da fitossociologia, a avaliacao da regeneracao natural possui grande importância, principalmente porque fornece subsidios para restauracao ecologica. Diante disso, este trabalho foi realizado com o objetivo de analisar a composicao e os parâmetros fitossociologicos da vegetacao arbustivo-arborea em areas de plantio de eucalipto (Corymbia citriodora) e de mata nativa na Floresta Nacional do Ibura, no estado de Sergipe. Para esta finalidade, foram demarcadas 20 parcelas e amostrados todos os individuos com diâmetro a altura do peito (DAP) ≥ 8 cm. A amostragem revelou 821 individuos na area de mata e 1.000 para a area de eucalipto. Esses individuos representam 84 especies e as areas apresentaram diferenca significativa na composicao de especies, sendo 61 na area de eucalipto e 65 na area de floresta, e apenas 40 comuns a ambas as areas. Observamos o predominio de individuos de especies pioneiras na area de eucalipto. Tambem encontramos diferenca significativa para a area basal, densidade relativa e dominância relativa, mas nao foram observadas diferencas significativas quanto a altura media. Conclui-se que o periodo de 35 anos nao foi suficiente para a recuperacao da area de eucalipto, a qual ainda se encontra em estagio sucessional mais inicial que a area de mata. EnglishAmong the various applications of phytosociology, the evaluation of natural regeneration is of great importance, mainly because it provides insights for ecological restoration. The objective of this study was to analyze the composition and phytosociological parameters of shrub and tree vegetation in areas of plantation of eucalyptus (Corymbia citriodora) and areas of native forest in the Ibura National Forest, located in the Sergipe state of northeastern Brazil. For this purpose, 20 plots were sampled and all individuals with a diameter at breast height (DBH) ≥ 8 cm were measured. Sampling revealed 821 individuals in the forest area and 1,000 in the eucalyptus area. These individuals represent 84 species and the areas presented a significant difference in species composition, with 61 in the eucalyptus area and 65 in the Forest area, and only 40 species were common to both areas. There was a predominance of pioneer individuals in the eucalyptus area. There also was a significant difference in basal area, relative density and relative dominance, but no significant differences were observed in average height. It was concluded that a period of 35 years is insufficient for the recovery of the eucalyptus area, which remains in a more initial successional stage than the forest area.