ESTIMATION OF SITE CLASS AND AVERAGE AGE IN UNEVEN-AGED PINE STANDS IN MEXICO

This paper deals with an investigation about the estimation of site cl ass and average age in uneven-aged pine stands in the Sierra Madre Ori ental, Nuevo Leon, Mexico. For this study, 20 sample plots of 0.05 ha were established in a 16 ha large uneven-aged natural stand of Pinus t eocate with different sites (site classes 1.5 to 11.5). The structure of the total stand and the stem populations of the sample plots are ch aracterized by a mixture of homogeneous tree groups with different age s (Tab. 1). Within the individual sample plots, the sample trees of th e different tree groups have almost the same site class, independent o f age and dimension. In the 0.5 ha sample plots, the age of the predom inant trees is considerably greater (up to 20 years) than the average age of the tree population. For this reason, to estimate the site clas s in these uneven-aged pine stands (both in the total stand and in the individual sample plots), you must use the mean age and the mean heig ht of the relevant tree population.