Effects of timber harvesting on coarse woody debris in red pine forests across the Great Lakes states, USA

Coarse woody debris (CWD) chronosequences were developed for managed and un managed red pine (Pinus resinosa Ait.) stands across the Great Lakes states . Throughout stand development, there is less CWD in managed than in unmana ged forests, and effects of management are strongest in young forests (0-30 years old). At stand initiation, CWD is 80% lower in managed than unmanage d forests, 20 200 versus 113 200 kg.ha(-1), while at 90 years, CWD is 35% l ower, 6600 versus 10 400 kg.ha(-1). Timber management especially affects sn ags. In young managed forests, snag biomass is less than 1% of that in unma naged forests, 150 versus 58 200 kg.ha(-1), while log biomass is 80% lower, 5000 versus 22 800 kg.ha(-1). This trend continues in mature forests (91-1 50 years old), where snag biomass is 75% lower in managed than in unmanaged forests, 1700 versus 6400 kg.ha(-1). Management has relatively little impa ct on total log biomass of mature forests but increases the biomass of fres h logs nearly 10-fold, to 1400 versus 150 kg.ha(-1). CWD in managed forests is highly variable, primarily related to thinning schedules in individual stands.