SHORT-TERM EFFECTS OF WOOD ASH FERTILISATION ON TWO DRAINED MIRES IN CENTRAL FINLAND

摘要

We studied the short-term (1-5 years) effects of wood ash on tree growth and ground vegetation on two drained mires in central Finland. The sites differed from each other especially with respect to the N content of peat. The treatments were loose wood ash 15 t ha~(-1) and an unfertilised control. Wood ash improved the nutrient status (P, K, and B) of trees and increased height growth within 2-3 years. The stand responses were more pronounced on N-rich than on N-poor sites. Wood ash reduced the abundance and species number of the bottom layer drastically. The field layer was less affected. The concentrations of heavy metals did not increase significantly in Scots pine, cloudberry and in-rolled paxil. Conversely, on some cases the concentrations of Cd and Ni were lowered in the vegetation at the ash-fertilised plots.