Carbon balance and fire emissions in Andean cypress (Austrocedrus chilensis) forests of Patagonia, Argentina.

Wildfires are disturbances that affect forest structure and dynamics. Forests and the atmosphere interact in different ways; one is by emitting carbon (C) through wildfires and recapturing it by photosynthesis of regrowing vegetation. Estimation of C emissions and uptake allows monitoring and inventorying C at stand, landscape, or regional levels. We indirectly estimated C and other greenhouse gas emissions and uptake following Intergovernmental Panel on Climate Change (IPCC) guidelines, and also using growth curves derived from real data, in three burned pure Andean cypress (Austrocedrus chilensis) stands in Patagonia, Argentina. The sites, termed INTA (humid), LACO (mesic) and CECE (xeric), were burned on different dates (1987, INTA; 1999, CECE; 2008, LACO). Nearby unburned stands with similar structural and floristic characteristics were used as analogues to make our estimations. Carbon losses represented 245, 225, and 215 t CO₂ ha⁻¹ for CECE, INTA and LACO respectively. Amount of carbon sequestered by post-fire vegetation depended on the time-lag from fire occurrence to date of sampling, whereas C uptake rates varied in time according to differences in site environmental conditions. Andean cypress seedlings present in burned stands suggest that outside the time needed, each site may recover not only lost C but also former structure and functions. We estimated carbon (C) emission and uptake in three severely burned Andean cypress stands of Patagonia, Argentina, that had similar pre-fire biomass but grew under different environments. Carbon emissions were similar in the three sites, but differences in environmental site conditions caused significant variation in their C recovery rates. [ABSTRACT FROM AUTHOR]