TEMPORAL AND SPATIAL VARIABILITY OF SOIL CO2 FLUXES IN A RECENT CLEARCUT OF LOBLOLLY PINE IN CENTRAL VIRGINIA

Several studies have observed that human activity is a direct contributor to rising atmospheric CO₂, which is predicted to cause catastrophic damage to global ecosystems without intervention. A proposed method of reducing anthropogenic CO₂ emissions suggests increasing the use of renewable biofuels as an alternative to fossil fuels. This method utilizes natural terrestrial carbon sequestration that occurs during the growth period of biomass crops to directly remove carbon from the atmosphere, potentially storing some carbon in soil. However, there are very few observations of ecosystem carbon fluxes from bioenergy cropping systems. In the spring of 2018, we erected an eddy covariance flux tower to monitor atmospheric carbon fluxes in a section of clearcut loblolly pine forest in central Virginia. In June of 2018, we began gathering soil flux data to provide temporal and spatial sampling of the soil fluxes recorded over the site. We collected soil flux data with a long-term chamber, survey chamber, and LI-8100A gas analyzer. Preliminary results indicate average daytime CO₂ soil fluxes range between 3.70-6.00 μmol/m²/s², in agreement with previously published results. We examine relationships between the soil and tower measured fluxes. We also examine relationships with soil texture, temperature and moisture, which could generate useful data for scaling the results. Our results help quantify the carbon balance, and ultimately the sustainability, of bioenergy crops.