Efecto del espaciamiento en la productividad y valor económico de melina clonal (Gmelina arborea Roxb.), Pacífico Central de Costa Rica

Melina has been cultivated in the country since the 1960s and is the main source of wood. The species has been genetically improved, reducing its cycle from 10 to 6 years. The objective was to determine the effect of planting density on productivity and commercial value. The research was conducted in a clonal trial of melina in Orotina, Central Pacific Costa Rica, where planting at 4x3.5 m, 4x3 m, and 4x2.5 m spacings were evaluated. Diameter, commercial volume, economic value, tree quality, and quality indexes were investigated. Analysis of variance and nonparametric Kruskal-Wallis analysis were performed using R programming for variables that did not meet regression postulates. Volume and appraisal were obtained using the Avalúos Forestales Program. The 4x3.5m spacing was significantly superior in all variables. Volume increment, commercial value, and productivity exhibited an exponential pattern, inverse to planting density. Clonal melina can grow at a rate of 6 cm DBH yr-1, 40 m3 ha-1 yr-1, and US$1,438 ha-1 yr-1 during its first 3 years with 714 trees ha-1. A higher DBH growth rate exponentially increases the proportion of sawwood and economic value of plantations.