Snag dynamics in post-harvest landscapes of western Newfoundland balsam fir-dominated boreal forests

We examined changes in standing dead tree (snag) density and biomass with time following harvest across a chronosequence of balsam fir (Abies balsamea) dominated boreal forests in western Newfoundland, Canada. Current snag management practices in Newfoundland recommend a minimum of 10 snags/ha on the post-harvest landscape. Snags declined significantly in the first two decades of the chronosequence. The rapid rate of decline in snag density which occurred immediately post harvest was likely attributable to windfall and domestic harvest for firewood. A second rapid rate of snag density decline occurred 10–15 years post harvest which potentially reflected the average lifespan of snags in western Newfoundland. Average snag densities approximated the minimum management goal during the period from 15 to 60 years since harvest (YSH). However, 53–60% of sites sampled in the 15–60 YSH period contained <10 snags/ha. Snag densities then increased with forest age, again reaching high levels 81–100 YSH which were comparable to the density at the beginning of the chronosequence. Achieving the goal of 10 snags/ha on all post-harvest sites in western Newfoundland, especially between 15 and 60 YSH, will require changes to current forest management practices.