Snags, and their lichen flora in old Estonian peatland forests

Abstract

In this study, we (1) explored the lichen floras of snags and living trees of Picea abies, Pinus sylvestris, Betula pubescens and Alnus glutinosa in the Estonian peatland forests, distinguishing tree species, snags with bark (S1) and snags without bark (S2); (2) measured the availability and characteristics of snags. On average, 42–64 snags ha were detected, but snag types differed in availability. Although S2 of Betula, Alnus and Picea were the rarest studied substrata, the highest numbers of lichen species were estimated to occur there. The lichen floras of S1 and S2 were distinct, with that of S1 resembling living trees. Tree species influenced the flora of living trees and S1 but not of S2; a similar pattern emerged in substratum acidity. 25% of the lichen species were unique to snags. Forest management activities should retain especially the naturally rare S2 of deciduous trees.