Tuesday, November 6, 2007 - 1:45 PM
214-4
Soil Carbon Stocks and Chemistry of Fire and Harvested Jack Pine Stands in Saskatchewan Canada.
Charlotte Norris1, Sylvie Quideau1, Jagtar Bhatti2, and Roderick Wasylishen1. (1) University of Alberta, 442 Earth Sciences Building, Edmonton, AB T6G 2H1, Canada, (2) Northern Research Centre Natural Resources Canada, 5320 122nd Street, Edmonton, AB T6H 3S5, Canada
Pine forests cover 20% of the North American boreal forest and jack pine (Pinus banksiana Lamb.) is the dominant pine species in central Canada Saskatchewan in 2004 were jack pine stands. Hence, the overall objective of this study was to quantify and compare changes in soil carbon stocks and chemistry in two jack pine chronosequences of either fire or harvesting origin. Three paired jack pine sites with variable time since fire or harvest (4, 12, and 30 yrs) were selected and compared to a mature (90 yr-old) stand. Total carbon stocks were determined for the A and B horizons, and the distribution of carbon among the labile (light fraction), and the physically, chemically, and biochemically stabilized pools was quantified using a combination of density and particle-size separation techniques. Composition of the organic matter in these fractions was characterized by CPMAS 13C nuclear magnetic resonance. Preliminary results indicate a decrease in total soil carbon content 10 years following disturbance, with a recovery to pre-disturbance levels by 30 years in both chronosequences. This is accompanied by an increase in the labile carbon contained in the B horizons, while the A horizons exhibit different responses following the two disturbance types.