SITE INDEX MODELS IN Swietenia macrophylla King PLANTATIONS IN QUINTANA ROO, MEXICO

Abstract

The success of commercial forest plantations (CFP) depends on essential knowledge of the productive capacity of the site. Site index (SI) curves help classify forest land based on the productive capacity for a given forest species. This study attempted 1) to fit dominant-height growth models as a function of age with a mixed-effects model approach and 2) to generate SI curves for CFPs of Swietenia macrophylla King in Quintana Roo, Mexico. Model adjustment contained 396 pairs of dominant height-age data from temporary plots collected in plantations aged seven to 43 years. The adjusted growth models were based on Schumacher, Korf, Chapman-Richards and Weibull. The Weibull and Chapman-Richards models with a random effect on the asymptotic parameter presented the best goodness of fit. The equation with the best graphic behavior when superimposing the generated curves against the observed data was Chapman-Richards in anamorphic form. The growth curve predicted a maximum height of 19.26 m. Temporal data allowed successful modeling of the dominant height growth pattern of Swietenia macrophylla and a nonlinear mixed effect model on the asymptotic parameter.