The Effect of forest age on hair lichen biomass in two production forests

Hair lichens are important organisms that provide many ecosystem services but their abundance has been declining in the last century. Loss of old forest has been a major cause of the decline. Increased forest productivity following climate change might lead to even shorter rotation times in the future. This study has investigated how the biomass of the hair lichen genera Alectoria, Bryoria and Usnea are affected by forest age in two forests. This was done by comparing the longest thallus lengths, which has a strong correlation to biomass, in one 100-110 years old forest to a 60-70 year old forest. 20 study sites were inventoried, 10 sites in the younger forest and 10 in the older forest. The biomass of Alectoria and Usnea was greater in the 100-110 years old forest compared to the 60-70 years old forest, while no difference was confirmed for Bryoria. Forest age is important since older forests provides longer colonization time and old trees, which are better substrate for the lichens. Shorter rotation times would probably not allow for recovery, especially for species less adapted to rapid long-distance dispersal, such as Alectoria sarmentosa