Deadwood occurrence and forest structure as indicators of old-growth forest conditions in Mediterranean mountainous ecosystems

"In order to identify the distinctive traits of old-growth forests in a Mediterranean context, deadwood occurrence and forest stand structures were investigated in some remote forest areas developedgrown in absence of anthropogenic disturbance over the past few decades. Five study sites in south-central Italy were selected and structural parameters were censed in 1-ha size plot. Living trees, deadwood amounts, types and their decay stages were inventoried in the selected sites. . Living tree volumes and amounts of deadwood indicate a large variability among the investigated forest stands, ranging from 363 to 702 m3 per ha for living trees and from 17 to 143 m3 per ha for deadwood. . Lying deadwood is the most abundant component, due to the natural mortality occurring in the stands in relation to the processes established in the last decades. Stumps are the less represented among the types of deadwood. All the decay classes are present in each study site. . The main structural features useful to characterize these forest stands characterized by old-growth forest conditions close to oldgrowthness include a multi-sized diameter distribution of living trees, the presence of small-scale gaps dynamics, tree height heterogeneity and high values of living volume and basal area. A ratio of dead to living wood not lower than 10%, lying deadwood much more abundant than the standing one, and large range of deadwood size and decay classes across all the deadwood components are useful traits for tracking these Mediterranean forests towards old-growth stages.. "