Our study addresses the ability of already established thalli of L. pulmonaria to survive and stay vital on trees retained at harvest (“life-boating”), i.e. dispersal aspects were not in focus. Nevertheless, colonization of new trees will be decisive for the species’ long-term persistence and thus is an essential aspect to investigate. Experiments

with diaspores of L. pulmonaria ( Scheidegger et al., 1995 and Hilmo RGFP966 cost et al., 2011) indicate that establishment, contrary to survival and growth, is hampered by light-exposed conditions, and establishment constraints in young forests have also been suggested by Gjerde et al. (2012). Further studies are needed to examine if habitat requirements indeed differ for different life-history stages in L. pulmonaria and other lichens. It might be surprising that no difference could be detected in either survival or vitality between transplants on aspens in groups and on scattered trees since tree groups could be expected to provide more semi-open conditions, beneficial to the lichen.

But, a tree group according to our criteria did not have to consist of more than four trees which means that the groups could be very small, and thus the difference to scattered trees was not pronounced. Further, several trees in groups had fallen at the inventory after 14 years, and a young forest stand had developed, leveling out differences in the environment surrounding scattered aspens and aspens in groups. Lack of natural young forests following fires in today’s European boreal forest landscapes MLN8237 in vitro could mask important occurrence patterns of species that today are viewed as confined to high forest ages; the few remaining intact forests are all old-growth. Recent research indicates that stand-replacing fires were less common and fire frequencies and intensities lower than earlier thought in N. Europe,

implying that there were usually numerous remnant trees in forests regenerating after fire (Kuuluvainen, 2009). It might be that such trees were important habitats for L. pulmonaria and other lichens. Thus, it can be discussed whether L. pulmonaria Niclosamide is a true old-growth lichen or if it is an old-growth species in the current N. European forest landscapes since natural early-growth forests are lacking. Only in the so far unlogged forest landscapes of N. Russia in which natural fire dynamics still remain would it be possible to study the association of L. pulmonaria and other epiphytic lichens described as sensitive, to different successional stages after natural disturbance. The importance to biodiversity of old-growth structures in early successional stages is today increasingly highlighted in ecology and conservation ( Kouki et al., 2004 and Swanson et al., 2011).