Carbon dynamics of aboveground live vegetation of boreal mixedwoods after wildfire and clear-cutting

Live vegetation carbon (C) pool dynamics are central to understanding C sequestration of forest ecosystems. Despite its importance, how aboveground live C pools change with stand development in boreal mixedwoods is poorly understood. We quantified aboveground live C pools (i.e., trees, >4 m in height; saplings and shrubs, 1.3–4 m in height; and understory plants, <1.3 m in height) in a postfire chronosequence ranging from 1 to 203 years and a postlogging chronosequence ranging from 1 to 27 years in the boreal mixedwoods of central Canada. The tree C pool of postfire stands increased from 0 to 109.2 Mg/ha from 1 to 92 years after fire and then declined to approximately 70 Mg/ha in 140- and 203-year-old stands. Carbon pools of saplings and shrubs and understory plants also changed with stand development and stand origin. Of the three age classes compared, postlogged stands had significantly higher vegetation C than postfire stands 1 and 27 years after disturbance, but there was no difference in 9-year-old stands. Higher values of live vegetation C in postlogged stands was attributed to live standing trees left after logging and silvicultural treatments that helped trees to establish during stand initiation.