70(1):125–132. Paper abstract bibtex
The epiphytic lichen flora on basal trunks of old Salir caprea and Populus tremula trees was surveyed in eight old-growth stands in the southern and middle boreal forests of Finland. Both the total species number and average species number per tree were higher on S. copra than on P. tremula. The epiphyte flora on S. caprea was dominated by widespread generalist foliose lichens. but some rarer specialists were also found. The flora of P. tremula was quite unique, and was dominated by crustose lichens and bryophytes, foliose and fruticose lichens being only sparsely represented. Cyanobacterial lichens, such as Lobaria spp., Nephruma spp. and Pelfigera spp., were frequent on both tree species. Structure And acidity of the bark, as well as the availability of different micro-habitats, arc suggested to be the most important factors contributing to floristic differences and di-versity. The bark of S. caprea and P tremula is one of the key habitats for conservation of epiphyte diversity in the boreal forests of Finland.