Forest management and genetic diversity of Pinus patula Schiede ex Schltdl, & Cham, in Sierra Juarez, Oaxaca

work focuses on the genetic study of Pinus patula Schiede ex Schltdl. & Cham., the most important species in the forest sector of the Sierra Juarez in Oaxaca, in order to evaluate the effect of forest management on genetic diversity of reforested sites and natural regeneration. It also seeks to determine whether the intensive logging of the mid-twentieth century genetically impoverished the species. Three microsatellites were used for six sites, covering three forest areas that had been managed for one, five and eighteen years, and three areas of natural regeneration. The resulting allelic richness (A o = 59 and A e = 16) and genetic diversity (H e = 0,802) was high, and there were no significant differences in genetic diversity between managed and natural regeneration sites. However, there was a lack of genetic structure (F st = 0,056) at sites with moderate gene flow ( N e m = 4,19). Furthermore, UPGMA cluster analysis suggested that the genesis of individual trees in the managed sites were taken from one site on Capulalpam de Mendez. In conclusion P. patula has not been genetically impoverished by present or past forest management and has characteristics in its life story that promote genetic diversity and high rates of inbreeding. Also, the great abundance of in-bred individuals in the sites are actually a dampening factor on allelic loss. However, an inadequate selection of parent trees and a low effective number of in-bred individuals can affect the stability of allelic frequency, and lead to considerable allelic loss in the future.