Characterization, structure and genetic dating of an old-growth beech-fir forest in the Northern Apennines (Italy).

An old-growth beech forest stand with silver fir within the strict forest reserve of Sasso Fratino has been examined with the following aims: to characterize forest stand on the basis of classic forest parameters and to assess forest stand structure by means of spatial functions; to provide genetic dating of the beech population. Total census of size and position of living trees and deadwood was performed on a 9200 m 2 permanent plot. Vertical distribution of crowns in the stand was assessed using the TSTRAT function, horizontal stand structure using spatial point pattern analysis. Genetic dating was performed on a sample of beech trees. DNA was isolated and each individual was genotyped at four chloroplast microsatellite loci. Microsatellite profiles were compared with the profiles of control DNA of known haplotypes. Results show a multi-strata vertical structure, a horizontal structure characterized by small gaps (<160 m 2) where silver fir regeneration sets in. Deadwood is present with all the decay classes and with relatively high volumes. Genetic dating ascribes the Sasso Fratino beech stand to the ancestral haplotype 2: this population can therefore be considered a hot spot of haplotype diversity of the glacial refugia present in central Italy.