The influence of forest management on beech (Fagus sylvatica L.) stand structure and genetic diversity

The influence of forest management on stand structure and genetic diversity was studied in a European beech (Fagus sylvatica L.) forest in the Gran Sasso – Laga National Park, Apennine Mountains, central Italy. Field work was carried out in two plots to compare both spatial structure and genetic variability between an old-growth beech stand and a post-harvest naturally regenerated stand. The study was based on a total census of living trees within the plots. Vertical and horizontal stand structures were analyzed by means of spatial functions. Individuals were genotyped with four highly polymorphic nuclear microsatellite loci (nSSRs) and with RAPD markers. Population spatial genetic structure was inferred using a Bayesian Monte Carlo Markov Chains method implemented in the Geneland software. The major structural differences distinguishing the old-growth stand from the managed stand were tree size differentiation, vertical crown distribution and horizontal stem distribution. Concerning genetic features, the managed stand presented no significant differences from the unmanaged stand. Nevertheless, the old growth forest had a higher spatial structuring of genetic diversity than did the managed stand. Molecular markers (nSSR alleles and RAPD fragments) detected in the unmanaged stand were rarely detected in the managed stand, and rare markers were lost.