Prognosis of growth and production of Eucalyptus urograndis planted at different spacings

Abstract

A topic of great interest in forestry research is recognizing the behavior of stands planted at different spacings to optimize the potential of producing multiple products. This study aimed to assess the future production of multiple products from Eucalyptus sp. planted at 12 different spacings. The study area was in central Brazil. A Nelder systematic design with three replications was used. This design yielded 432 planting spots per plot per replicate. Diameter at breast height (DBH) and total height were measured for all trees from 4 to 36 months of age. In addition, the volume of five trees for the spacings of 16, 24, and 36 months of age was measured. Subsequently, an equation system was fitted for each area to project the Weibull 3P probability density function parameters: minimum diameter, maximum diameter, and the number of trees. The current and mean annual increments were assessed based on the total volume. Trees of 36 and 48 months of age were compared between the population designed for multiple products (Scenario I) and the population designed for only one product (Scenario II). The results showed that spacing affects the technical harvest age and that 0.77 m² and 1.76 m² are optimal for a short-term regime