Lichen habitat may be enhanced by thinning treatments in young Tsuga heterophylla-Pseudotsuga menziesii forests

Abstract

Abstract Forest structural characteristics manipulated by alternative thinning treatments were associated with increases in cyanolichen and alectorioid species richness and changes in lichen community compositions. At two sites in moist conifer forests of western Oregon, lichen community monitoring plots were established before thinning treatments; the most diverse plots in each treatment were retained as diversity islands whereas the less diverse plots were treated in the thinning prescription. We resampled these plots approximately 10 years after thinning. At one site we found that lichen communities in diversity plots were quite similar to those in the surrounding treated forest and that the proportion of Tsuga heterophylla in the stand was negatively associated with alectorioid and cyanolichen richness. At both sites, hardwood gaps and open-grown trees were positively associated with cyanolichen species richness. At the other site, surrounding plots were more like diversity “leave-islands” after thinn...