Investigations on heavy metal and SO2 polluted forests in Kola peninsu
la indicated strong soil acidification at a distance of 20-30 km from
the strongest SO2 emission source. Toxic concentrations of Ni and Cu i
n the soil organic layer was supposed to affect tree vitality. Stepwis
e regressions indicated strong negative effects on needle loss, needle
age classes and needle weight due to the accumulation of Ni. Direct e
ffects of SO2 could not be evaluated. From comparison with industrial
areas with more fertile and phosphorous rich soils it was concluded th
at the negative effects of heavy metals and SO2 could be counter-acted
. (C) 1998 Elsevier Science Ltd.