Carbon Losses from Decomposing Windrowed Sitka Spruce Woody Debris Over a 16-Year Chronosequence

Meeting the reporting requirements of Kyoto Protocol has focused attention on potential forests in sustainably sequestering carbon (C) to mitigate effects rising levels atmospheric CO2. Much uncertainty remains concerning ultimate effect management such sequestration effects. The woody debris (WD) and other deadwood stocks is an example a intervention with scope affecting source-sink dynamics forest C. Windrowing most commonly employed approach post-harvest WD. This study investigated quantities windrowed C across chronosequence reforested commercial Sitka spruce stands Ireland how its decomposition rate affected contribution sequestration. WD ranged from 25 8 t ha?1 at 4- 16-year-old stands, respectively. Losses due these 5.15 yr?1 youngest site (4 years old) 0.68 oldest (16 old). Using visual decay-class categorization components assessment wood density, decay constants were estimated for logs, branches, stumps (the main constituents windrows) as 0.037, 0.038, 0.044, These results, derived stand stock evaluations, placed into context data previously published same that characterized day-to-day fluxes or this pool. comparison indicated though only very small quantity was lost dissolved leachate form, significant pathway loss respiratory 16 9- sites. estimates many times greater extent than made using density-loss approach, difference indicating fragmentation weathering play large role intensively managed forests.