Arranjo estrutural e dinâmica de crescimento de Eucalyptus spp., em sistema agrossilvipastoril no cerrado

Abstract

This work evaluated the silvicultural and productive behavior of Eucalyptus spp. under four different structural arrangements of agrosilvipastoral system in cerrado of Minas Gerais in five points in time till 67 months of age. The experiment was established in December of 1999 in a cerrado area of Votorantim Metais, in the Northwestern of Minas Gerais (Paracatu, MG, Brazil). Clonal seedlings of a natural hybrid of Eucalyptus camaldulensis Dehnh with Eucalyptus urophylla S.T. Blake were planted for lumber production. The mixing with rice in the first year, soybean in the second and Brachiaria brizantha for the following years was established. The utilized experimental design was randomized blocks, composed of 4 treatments (3.33 x 2m, 3.33 x 3m, 5 x 2m and 10 x 2m) with five replicates.The experiment was evalueted at 18, 27, 38, 51 and 67 months post-planting. It was found that till the 18 months of age, the volume per plant showed no differences among the distinct arrangements, but being bigher in the widest arrangement (10 x 2m) from the 38 months post-planting. From the second year on, the larger the useful area the larger was he DAP. As time past by the growth rate decreased in the most reduced spacings. It was found also that the individual production was larger in the widest spacing and, till the 67 months, the stand yield was more influenced by the number of individuals per area than by the structural arrangement.