Site Quality for Mahogany (<i>Swietenia macrophylla</i> King) in Natural Forests in Quintana Roo

The concept of site quality was developed to project the expected production of timber species in even-aged stands in order to produce standardized site index curves. This concept can also be used in a more ecological sense to discern the spatial growth patterns of timber species in natural forests. We used the height-diameter relationship to evaluate a method to determine site quality for Swietenia macrophylla King in natural forests in Quintana Roo, Mexico. Using linear models and analysis of covariance, we detected significant and notable differences in mahogany development (p < .001), with some trees exceeding the predicted height by more than one meter. These differences were related to micro-topographic and edaphic factors and to the spectral response of the vegetation. Using a predictive model of site quality to develop a site quality map, we also determined that 86% of the production forest in the study area fit in the low productivity category, with mahogany growing below the predicted height for the area. These results suggest that site quality maps can contribute to effective forest management where forest aptitude is not homogeneous for timber growth. Concentrating management practices on high quality sites has the potential to conserve investment resources and increase production.