VARIABLES AMBIENTALES QUE DETERMINAN LA REGENERACIÓN NATURAL DE PINOS EN ECOSISTEMAS ALTERADOS POR INCENDIOS

Environmental factors influence positively or negatively for the establishment of natural pine s regeneration, which may be linked to forest fires. Therefore, the objective of this study was to determine the environmental variables that influence the establishment of natural pines regeneration in impacted areas under three fire severity conditions (no fire, moderate fire and extreme fire) in pine - oak forests (Pinus lumholtzii BL Rob. & Fernald, Pinus devoniana Lindl., Pinus oocarpa Scheide, Quercus castanea Née, Quercus magnoliifolia Née) in the state of Jalisco (Mexico). For this purpose, different parameters of natural regeneration were evaluated: trees, live and dead fuels in circular sites of ~400 m2. Correlation analyses were performed with the data obtained to identify the most significant variables, and to use them in the stepwise regression analyses to identify predictor variables useful for the definition of the model for the estimation of natural pine regeneration in areas affected by fire. The analyzes showed that the "stepwise" process presents the best model with an R2 of 0.6837 and an AIC of 568.58, selecting the following variables: dry weight of herbs, height of shrubs, crown diameter of shrubs and grasses, 10 hour fuels and exposure. Subsequently, considering the mean square of the error as the main criterion, a comparison was made of the models resulting from the combination of these variables, with the best model excluding the dry weight of herbs. It is concluded that the establishment of the natural regeneration of pine is associated with certain variables of ground cover, understory and relief.