Amount and quality of coarse woody debris in natural and managed coniferous forests near the timberline in Finnish Lapland

Amount and structural characteristics of coarse woody debris (CWD) were studied in 44 stands of old-growth and managed coniferous forests in Finnish Lapland. The average volume of CWD in old-growth forests varied from 19 m3 ha-1 in pine forests to 60 m3 ha-1 in herb-rich spruce-dominated forests. The volumes of living and dead timber were highly correlated, the most productive sites having the highest volumes. In old-growth forests about 60-70% of the CWD was logs, 30-40% standing dead trees and snags, and 3.5-7% stumps and branches. The amount of CWD decreased considerably in clear-cutting, but increased or remained the same in seed-tree and selective cuttings in the short term. However, the accumulation rate of new dead material was greatly reduced after cutting. In 40-year-old seed-tree cutting areas the new supply of CWD, created by recent disturbance and mortality, was less than 1% of the respective amount in old-growth forest. All cutting methods reduced standing dead trees and snags considerably.