EPIPHYTIC LICHEN DIVERSITY IN OLD-GROWTH AND MANAGED PICEA-ABIES STANDS IN SOUTHERN FINLAND

Epiphytic and epixylic lichens were surveyed on 15 1-ha plots in matur e Picea abies-dominated boreal forests in southern Finland. The sample plots were classified into three groups according to the age of the d ominant tree stand and recent signs of cutting: (1) early mature manag ed, 'EM' (95 - 109 yr), (2) late mature managed, 'LM' (126 - 145 yr) a nd (3) old-growth, 'OG' (129 - 198 yr). Two data sets on epiphytic and epixylic lichens were recorded from each plot: (1) species on basal t runks and branches of Picea abies and (2) species on all available woo dy substrates, including basal parts of all tree species, saplings, sn ags, logs and stumps. 142 epiphytic and epixylic lichen species were f ound, of which 83 (58 %) occurred on P. abies. Mean total numbers of s pecies per sample plot were 69 in EM, 78 in LM and 88 in OG plots, spe cies number on P. abies were 47, 56, and 54 respectively. The LM plots had lower species numbers than OG plots, mainly due to the lack of ol d Populus tremula trees, but they had higher species number than the E M plots mainly due to the higher age of Picea abies. Differences in sp ecies composition, both within and between the three groups, were smal l. The results suggest that the epiphytic and epixylic lichen diversit y in a managed stand can be increased by prolonging the rotation of th e stand to > 120 yr and by increasing the diversity of habitats in the stand.