Impact of selective logging on genetic diversity and population structure of Oriental beech (Fagus orientalis) in the relict Hyrcanian forest

Selective logging may affect genetic diversity and genetic structure of tree populations. Oriental beech ( Fagus orientalis Lipsky) is the most economically significant species in the Hyrcanian forests. We investigated impacts of selective harvesting on genetic diversity and population genetic structure of Oriental beech 20 years after the harvest. Four locations were selected in the Hyrcanian forest and at each location an unmanaged control and a selectively logged population were studied. The genetic diversity and population genetic structure of the sampled populations were determined by using nine SSR markers of the nuclear genome. In total, 276 alleles at 9 nuclear microsatellite loci were detected. Allelic diversity, observed and expected heterozygosity, inbreeding coefficient, and effective population size estimates were statistically similar ( p > 0.05) between unmanaged control and selectively logged Oriental beech populations. On average, genotypic diversity was higher in the unmanaged populations as compared to the selectively logged populations but the differences were not statistically significant ( p > 0.05). The number of rare alleles was reduced in the post logged populations at the 5% criterion but not at the 1% criterion. At two of the four locations, selectively logged populations were highly genetically differentiated from the unmanaged populations. While selective logging did not appear to have negative effect on genetic diversity and effective population size, it may have contributed to change the genetic structure of the post logged populations and insignificantly reduced genotypic diversity. Our study has implications and applications for sustainable management and conservation of genetic resources of Oriental beech and other beech species.