Another important measure is to leave aspens during pre-commercial and commercial thinnings, to guarantee a continuous supply of aspens of different sizes and ages over time. The higher transplant survival on aspens on northern sides of trees in clearcuts than in forests indicate that the species is promoted by semi-open conditions with moderate light levels, which benefit growth

but are not strong enough to cause fatal damage (Gauslaa et al., 2006). Many old forests with aspens in Fennoscandia are today darker and denser than before, when there were more fires and cattle grazing. For several decades there has been vigorous check details in-growth of P. abies in these forests, creating a dark climate which is likely negative for L. pulmonaria.

Thinning and selective felling of spruce is an efficient method to create more favorable conditions for this species and other lichens of the Lobarion community. The preference for rather open canopies in boreal forests is also shared by other rare lichen species like the long-beard lichen Usnea longissima Ach. ( Josefsson et al., 2005). Our transplantation experiment shows that aspens retained at final harvest provide good habitat for L. pulmonaria and thus that leaving aspens unlogged is an efficient conservation measure. Transplantation of lichens is an informative method to address conservation biology questions related to epiphytes and can yield AZD2281 valuable insights already after short time spans. However, long time-series are needed to identify more specific response patterns. Optimally, real occurrences should be followed over time, but in the case of L. pulmonaria, which is uncommon in Sweden today, finding large sample sizes is impossible if

variation in forest ages and site conditions are to be controlled for. Still, extensive surveys of this lichen and the whole epiphytic lichen community connected to aspen in different forest ages would yield a deeper understanding necessary for development of isothipendyl more fine-tuned conservation recommendations. We are grateful to the Forestry Research Institute of Sweden (Skogforsk) for financial support during the setting up of the experiment and the first survey. The Swedish Research Council Formas gave economic support for the second survey within the research programme “Smart Tree Retention” (Grant 215-2009-569 to LG). We also thank Mikael Andersson for helpful advice on the GLMM approach. “
“In recent decades, many forest scientists have investigated resource use efficiency of trees and forests. Efficiency is defined as the ratio between some measure of biomass production and a measure of resource supply or use. The numerator could be gross primary production, net primary production or stemwood increment over a defined time period. Many different measures of resources have been used as a denominator, quantifying either light, water or nutrients.