Bancos de sementes do sub-bosque de Pinus spp. e Eucalyptus spp. na flona de Brasília

Abstract

An analysis of the soil seedbank from the understory of Pinus and Eucalyptus in the Floresta Nacional de Brasília was performed, these plantations were established in the 1980s, and since 1987 have not had adequate management. Two stands of each genus were chosen, with and without gaps. In each one of these stands 15 plots of 2 x 2 m were implanted, where a sample of 0,30 m x 0,30 m of soil and two sub-sample of 0,125 x 0,15 m of litter were collected for a quantative and qualitative analyzis of the seedbank. The medium density of seedlings emergence in the Pinus stand was 3.098,19 seeds.m-2 while for the Eucalyptus it was of 2.077,19 seeds.m-2, which means that the seedbank from the Pinus understory area has a higher regeneration potential than the Eucalyptus plantations. The Pinus plantations contained in the understorey: 12 families, 25 genus and 39 species, while in the Eucalyptus: 14 families, 31 genus and 48 species, proving more richness in the Eucalyptus seedbank. In both genuses the most important families were Poaceae and Asteraceae. Both Pinus and Eucalyptus seedbanks populations, with or without openings, proved that the more interference in its population higher is the number of seeds from herbaceous species in comparison to tree species. The Sørensen similarity índex applied to analyze the seedbanks in the four areas, both for soil fractions and litter, was low, 0,5 and 0, 486, respectively.