Historical Changes in Abundance and Structure of Oak Populations under Management in Sierra Juárez, Oaxaca, Mexico

Harvesting tree species for local and commercial use can lead to habitat losses potentially affecting ecosystem dynamics and the biodiversity of temperate forests. For example, selective extraction of conifer species in Sierra Juárez (Mexico) has led to a loss of ecologically significant species such as oaks. This study examines the impact of three different management systems (viz., local use, silvicultural development, and clear-cutting) on oak populations in silvicultural areas of Sierra Juarez (Oaxaca, Mexico). Changes in oak abundance and structure over time were investigated from evidence for size-classified stumps and resprouts. The results revealed significant differences in abundance, size structure and spatial distribution among oak trees between periods and management systems. Thus, local use caused no substantial decrease in oak density, but reduced tree mean diameter, whereas silvicultural management considerably decreased oak density, and clear-cutting reduced both oak density and mean diameter. Based on the results, forest management practices to be adopted in the framework of conservation strategies should be designed with provision for oak life history and habitat heterogeneity. As also shown by the results, differences in harvesting practices result in dissimilar impacts on oak populations and emphasize the need for conservation efforts to preserve the ecological integrity of forests.