Uniformidade entre árvores durante uma rotação e sua relação com a produtividade em Eucalyptus clonais

Abstract

Tree clonal plantations have identical growing capability. However, operational failures lead to heterogeneous resources supply, resulting in losses of uniformity. Scientific evidences have shown heterogeneity between plants interfere on wood productivity. Nevertheless, few studies relate uniformity since the beginning of rotation and determine relationship between productivity and uniformity. So, we aim to investigate the behavior of uniformity along a rotation and its relationship with productivity in Eucalyptus clonal plantation. For this, a randomized block experiment was replicated in three experimental sites. A uniform treatment, with all seedlings planted at the same time was contrasted with a heterogeneous treatment, where a third of seedlings were randomly planted on days 0, 40 and 80. Productivity and uniformity were determined quarterly from 12 to 72 months. In both treatments uniformity peaked at the time of canopy closure and was gradually reduced until the end of the rotation. However, since the beginning the heterogeneous treatment was less uniform than the uniform treatment for all sites, reaching an average difference of 119% for the PV50 at the end of rotation. Initial uniformity (12, 18 and 24 months) was highly correlated with final productivity (72 months) (R² >0,67; p<0,001) and also with final productivity (R² >0,43; p<0,001), being the more productive stands the ones with higher uniformity. Results point to the importance of a silviculture management that provides homogeneous resource supply.