O ensaio foi instalado em novembro de 1977 na Estação Experimental de Recursos Naturais Renováveis de Anhembi. Avaliou-se o efeito de cinco diferentes espaçamentos 3,0 × 1,5m; 3,0 × 2,0m; 3,0 × 2,5m; 3,0 × 3,0m e 3,0 × 3,5m, sobre o crescimento em volume das espécies Pinus oocarpa e Pinus caribacea var. Hondurensis. Este estudo teve como objetivos determinar o espaçamento ideal de plantio, visando obter maior produção volumétrica total de madeira, em rotação longa para serraria e laminação e, avaliar os incrementos corrente e médio anual em volume, para diferentes espaçamentos até fase do primeiro desbaste. O diâmetro médio quadrático atingiu maiores dimensões no espaçamento mais amplo (3,0 × 3,5m). Desta forma, obteve-se maior produção volumétrica total de madeira, com o Pinus oocarpa e Pinus caribacea var. Hondurensis, nos espaçamentos 3,0 × 1,5m (685m₃/La) e 3,0 × 3,5m (659m₃/ha) respectivamente, e com Pinus oocarpa, 581,90m₃/ha, no espaçamento 3,0 × 1,5m. Assim sendo, o espaçamento 3,0 × 3,5m é o mais indicado silviculturalmente para se obter madeira destinada a serraria e laminação, pois foi o que apresentou maior volume total de madeira e, o que concentrou maior número de árvores com diâmetro de maiores dimensões

The field trial was stablished on november of 1977 at the Anhembi Experimental Field Station of Natural Renewable Resources. The effect of five different spacing was evaluated (3.0 x 1.5 m; 3.0 x 2.0 m; 3.0 x 2.5 m; 3.0 x 3.0 m e 3.0 x 3.5 m), according with volume increments of Pinus oocarpa and Pinus caribaea var. hondurensis. The aim of this study was to determinate the best planting spacing, in order to obtain the highest wood productivity in total volume, associated with long rotations for plywood veneer and sawmill use. This study also evaluated the mean and the net annual increments in volume, for each spacing tested until the first thinning operation. The mean quadratic diameter attained highest measures in the wide spacing (3.0 x 3.5 m). Therefore the highest wood productivity in volume was obtained for P. caribaea var. hondurensis, at 3.0 x 1.5m spacing (685 m₃/ha) and 3.0 x 3.5 m spacing (659 m₃/ha), and for P. oocarpa, at 3.0 x 3.5 m spacing (581.90 m₃/ha). Thus, 3.0 x 3.5 m spacing is most indicated to stablish plantations for timber production, whereas it demonstrated the higher total wood volume and, since it concentrated the number of trees with the largest diameters. At the age of nine years, P. caribaea var. hondurensisP. caribaea var. hondurensis and P. oocarpa, respectively. According to the adjustement of regression equations, the mean and the net annuaI increment curves, at the age of fourteen years, have not crossed yet, indicating that the optimum thinning age must occur on a later period for the two studied species. The thinning operation realized at the age of fourteen years, demonstrated that a more wide tree spacing with higest diameters, showed better responses for total volume, in comparison with a more closed tree spacing. This assumption can be associated with the fewer competiton between trees.