Analysis of 19-year-old planted Pinus caribaea var. hondurensis on clay and sandy soils in the mountains of Puerto Rico showed the suitability of both sites for tree growth to commercial size. Growth rates were compared with tree densities ranging from 278 to 2,500 trees per hectare and tree dbh’s (trunk diameters outside bark at breast height, 1.4 meters above ground on the upper side) from 10 to 40 cm. With angular spacing tree growth was found related to that of six equidistant adjacent trees. Frequent past remeasurements exposed tree growth trends with changes in the density of surrounding trees. Regressions of tree diameter growth based on relative basal area tree density had coefficients of determination (R2) of 0.76 and 0.77 for clay and sand, respectively. As a guide to tree planting spacing and thinning for any plantation productivity goal a table is presented showing predicted time requirements to grow each 10 cm in dbh, mean annual dbh growth rates, and approximate periodic productivity of usable wood in m3/ha/yr. On comparable sites this table permits managers of plantations with any spacing and mean tree dbh to predict current growth, number of years to any mature tree size, the approximate yield at that time, and tree growth stimulation after thinning of different intensities at different times.College of Arts and Sciences University of Puerto Rico, Mayagüez