From Farms to Forests: Landscape Carbon Balance after 50 Years of Afforestation, Harvesting, and Prescribed Fire

Abstract

Establishing reliable carbon baselines for landowners desiring to sustain carbon sequestration and identify opportunities to mitigate land management impacts on carbon balance is important; however, national and regional assessments are not designed to support individual landowners. Such baselines become increasingly valuable when landowners convert land use, change management, or when disturbance occurs. We used forest inventories to quantify carbon stocks, estimate annual carbon fluxes, and determine net biome production (NBP) over a 50-year period coinciding with a massive afforestation effort across ~80,000 ha of land in the South Carolina Coastal Plain. Forested land increased from 48,714 ha to 73,824 ha between 1951 and 2001. Total forest biomass increased from 1.73–3.03 Gg to 17.8–18.3 Gg, corresponding to biomass density increases from 35.6–62.2 Mg ha−1 to 231.4–240.0 Mg ha−1. Harvesting removed 1340.3 Gg C between 1955 and 2001, but annual removals were variable. Fire consumed 527.1 Gg C between 1952 and 2001. Carbon exported by streams was <0.5% of total export. Carbon from roots and other harvested material that remained in-use or in landfills comprised 49.3% of total harvested carbon. Mineral soil carbon accounted for 41.6 to 50% of 2001 carbon stocks when considering depths of 1.0 or 1.5 m, respectively, and was disproportionately concentrated in wetlands. Moreover, we identified a soil carbon deficit of 19–20 Mg C ha−1, suggesting opportunities for future soil carbon sequestration in post-agricultural soils. Our results provide a robust baseline for this site that can be used to understand how land conversion, forest management, and disturbance impacts carbon balance of this landscape and highlight the value of these baseline data for other sites. Our work also identifies the need to manage forests for multiple purposes, especially promotion of soil carbon accumulation in low-density pine savannas that are managed for red-cockaded woodpeckers and therefore demand low aboveground carbon stocks.

Impact of agricultural abandonment on soil organic carbon: The case of semi‐steppe rangeland in Central Iran

“…The deletion of the disorder of cultivation practices and improving aggregate stability over the chronosequence of land abandonment could also contribute to the substantial increase in SOC sequestration from AR soils during decomposition. The results of our findings are also in line with the findings of studies by Aubrey et al (2019), Dar et al (2020), and Durán Zuazo et al (2020). Their findings show that increasing the amount of C through plant residues in the soil surface will lead to an increase in the amount of CR, N, and SOC in the soil.…”

Eucalyptus Are Unlikely to Escape Plantations and Invade Surrounding Forests Managed with Prescribed Fire in Southeastern US

“…Approximately 6000 to 8000 ha of pine forests are managed with prescribed fire annually, with targeted burn frequencies averaging between 2-4 years [40]. See Aubrey et al [41] for a detailed description of the site and its recent forest history.…”

Water use in a young Pinus taeda bioenergy plantation: Effect of intensive management on stand evapotranspiration

“…Measurements were taken from April 2016 to October 2018 in a 119.8‐ha watershed at the US Department of Energy Savannah River Site, a National Environmental Research Park located in the Piedmont of the Upper Coastal Plain physiographic region in South Carolina (33.2583 N, 81.6083 W), which is managed by the US Forest Service. The study site is representative of forests in this area in that it was primarily agricultural fields before it was reforested in 1951 (Aubrey et al, 2019; Griffiths et al, 2018). The climate is humid subtropical with long‐term average annual air temperature of 17.9°C; the lowest average temperatures occur in January (8.2°C) and highest in July (33.2°C).…”