Mapping of the epiphytic lichens on conifers in Finland in the years 1985–1986 and 1995

A systematic mapping of thirteen epiphytic lichen species on conifers was carried out in Finland at the first time in 1985–1986 and the second time in 1995. The aim of mapping work was to describe the regional distribution of the most common epiphytic lichens and to assess air quality based on the abundance of epiphytic lichens. All lichen species demonstrated increases in their abundance between the years 1985 and 1995. Scoliciosphorum chlorococcum, a species tolerant to air pollution, increased most in parts of the southern Finland where the nitrogen levels are relatively high. This indicate increased levels of nutrients in the forests. On the other hand, sensitive lichen species had become more common particularly in the central parts of the country, which is in agreement with decreasing sulphur deposition. The climate, tree species, stand age etc., however, mainly determining the distribution and the abundance of epiphytic lichens in Finland.