Carbon and energy exchange in a recently burned Jack Pine forest, Quebec, Canada

Fire is the most pervasive disturbance in the boreal forest system, playing a key role in regulating carbon (C) movement between the biosphere and atmosphere. The magnitude of ecosystem C sequestration is governed by internal processes, i.e. photosynthetic influx and residence time in plant, litter and soil pools, while being driven by global climate change and disturbance regime shifts. A potential climate warming effect may be a modified fire regime, with important ramifications for long-term soil C sequestration through altered forest functioning. Increased disturbance frequency and severity could result in forest stands unable to fully recover, reducing C storage ability. Given that boreal forests account for as much as 25% of global terrestrial C, it is imperative that we quantify forest fire recovery with respect to ecosystem level C dynamics. In this study, the eddy covariance technique is being used to measure C and energy exchange continuously at a boreal forest site, near James Bay, Quebec. A severe wildfire in 2005 resulted in the fatal damage or complete combustion of all above-ground biomass, as well as the removal of organic soil layers; Jack Pine saplings are the dominant vegetation re-growth. The objective of this study is to determine the environmental controls on intra and inter-annual variations in net ecosystem exchange (NEE), with the intention of comparing to studies from the west Canadian boreal forest. We hypothesize that the 6-year old burn stand is a daily sink during the growing season and has recovered to being a net annual sink, due to rapid sapling growth. This study aims to further the understanding of forest recovery from fire in the east boreal, an area understudied. This poster will present results from the summer and fall of 2011.