Site Index Curves for Abies borisii-regis Mattf. and Fagus sylvatica L. Mixed Stands in Central Greece

Abstract

Despite their productivity, fir and beech forests in Greece lack site index curves. In this work, site index curves for Fagus sylvatica and Abies borisii-regis in central Greece were developed. Thirty plots were randomly established in the mixed stands of F. sylvatica–A. borisii-regis in Aspropotamos, central Greece, and two dominant trees, one from each species, were randomly selected and cut. Height–age measurements were collected through stem analysis. These data were used to develop site index curves for each species. The site index curves illustrate a growth rate difference between the two species, specifically in the worst sites, with fir growing faster than beech. Additionally, as trees age, the growth difference between the two species in the best sites decreases. Based on these results, F. sylvatica is found to be more site-sensitive than A. borisii-regis. In the new adverse conditions of global warming, an increased knowledge of the site sensitivity of the two species will help to develop appropriate treatments for the conservation of the studied mixed stands, or at least to minimize negative impacts.