Soil CO₂ evolution in Florida slash pine plantations. I. Changes through time

Soil CO 2 evolution rates were measured in slash pine (Pinuselliottii) plantations of three ages in north Florida. At the mature (29-year-old) plantation, which had a closed canopy and a well-developed forest floor of litter and humus overlying the mineral soil, C storage in detritus in the mineral soil was relatively low and soil C release was relatively high (13.0 t•ha −1 •year −1 ). C release was highest (22.7 t•ha −1 •year −1 ) at the clear-cut site, presumably because of high temperatures and rapid decomposition of detritus added during the harvest, and lowest (8.2 t•ha −1 •year −1 ) at the 9-year-old plantation. For a range of forest sites, soil CO 2 evolution rates and the magnitude and direction of changes after harvesting show latitudinal variation that probably depends not only on the amount of C contained in dead organic matter in the soil and its decomposition rate but also on the treatment of slash left after harvesting.