Site factors determining epiphytic lichen distribution in a dieback-affected spruce-fir forest,on Whiteface Mountain, New York: microclimate

Relationships between microclimatic site factors and cover of epiphytic lichen species were studied in a dieback-affected forest of Picea rubens and Abies balsamea on Whiteface Mountain, New York, U.S.A. Canonical correspondence analysis revealed an effect of light and water relations on epiphytic lichen abundance, but these factors only accounted for less than 10% of total variance in species data. Neither light nor evaporation, relative humidity, water-holding capacity of bark, or air temperature differed at the trunks between trees of different species or vitality. These results suggest that microclimate is probably not the main cause of significant differences in the epiphytic lichen diversity of spruce and fir and of living trees and snags. However, as canopy structure at the study site changed recently due to dense young growth of A. balsamea, it is possible that past differences in microclimate still exert an influence on present-day within-stand variation of epiphytic lichen abundance.