Spatial distribution patterns of trees in a mixed pine-oak forest of Northeastern Mexico

The objective of this study was to characterize the tree spatial structure patterns of the mixed pine-oak forest in the northeast part of Mexico. A point pattern analysis was conducted in order to evaluate the following indices: aggregation index, mingling species index, dimensional (dbh and height) index and dominance index. The data were collected from 2 stands of 1 ha each. The variables obtained for all trees were: Azimuth and distance of each tree to the center of the stand, DBH, species, and height. The data were analyzed for each stand and also as a groups corresponding to the most abundant genera in the stands: (Pinus, Quercus, and Juniperus). The results show that according to the aggregation index (W-i) bothstands presents a random distribution, the mingling species (M-i) shows a higher mixture at both stands and the dimensional index shows moderate differences in DBH and height in both stands. The main differences were found using the dominance index (U-i) based on the groups; by this means a particular and local fire regime was identified for the area. The use of spatial analysis and the quantification of stand structure help to depict a detailed status of the forest and also the effects of disturbance on the forests. (C) 2017 Universidad Nacional Autonoma de Mexico, Instituto de Biologia.