Kaye, Jason (Penn State Univ., Department of Crop and Soil
Sciences, 116, ASI Building, University Park, PA, 16802; Phone: 814-863-1614;
Fax: 814-863-7043;
Email: jpk12@psu.edu)
J. Kaye *, J. Romanya, R. Vallejo
Fire regimes constrain carbon (C) accumulation in forests and recent research suggests that forest fires play an important role in C budgets for countries with expansive dry temperate forests. In Spain, dry, fire prone Mediterranean woodlands cover much of the country, including the northeast portion of Cataluna, where we used a chronosequence to estimate changes in ecosystem C storage following stand-replacing fires. In 2001, we sampled eight sites that ranged from 1 to 30 years post-fire. Several of these sites had been sampled for C storage in 1985 and 1989, so we were able to compare the chronosequence approach with repeated sampling of individual sites. Post-fire C accumulation in plants was low (less than 400 g C/m2) when shrubs dominated early in succession, but became substantial (about 5000 g C/m2) later in succession when pines became dominant. Soil C sequestration varied by layer. The surface organic horizons (Oi plus Oe) accumulated C rapidly early in succession and reached a maximum storage of 600 g C/m2. In contrast, the lower organic horizon (the Oa horizon) lost 200 to 300 g C/m2 within 15 years of the fire. Surface mineral soils (0 to 5 cm) lost as much as 2000 g C/m2 within the first 15 years following fire, but sites were highly variable in mineral soil C loss. To fully understand post-fire C storage in these woodlands, future research should focus on controls on pine regeneration and C losses from surface mineral soils.