Region-Wide Soil Carbon Assessment Across "the Land of Pines"

Thursday, 17 December 2015
Poster Hall (Moscone South)
C. Wade Ross1, Sabine Grunwald2, Eric J Jokela3, Stefan Gerber4, Steve Del Grosso5, Jason G Vogel6, Allan R Bacon7, Josh Cucinella3, Katherine Akers8, Adam Maggard9, Marshall A. Laviner10, Carlos A Gonzalez-Benecke11, Timothy Martin12, Rosvel G Bracho7, Daniel Markewitz8, Thomas D. Fox10, Harold Burkhart10, Michael Kane8, Gary F Peter3 and John M Davis7, (1)University of Florida, Soil and Water Science, Ft Walton Beach, FL, United States, (2)University of Florida, Soil and Water Science, Gainesville, FL, United States, (3)University of Florida, School of Forest Resources and Conservation, Gainesville, FL, United States, (4)University of Florida IFAS, Gainesville, FL, United States, (5)USDA-ARS Soil Plant Nutrient Research, Fort Collins, CO, United States, (6)Texas A & M University College Station, College Station, TX, United States, (7)University of Florida, School of Forest Resources and Conservation, Ft Walton Beach, FL, United States, (8)University of Georgia, Athens, GA, United States, (9)Oklahoma State University Main Campus, Stillwater, OK, United States, (10)Virginia Polytechnic Institute and State University, Department of Forest Resources and Environmental Conservation, Blacksburg, VA, United States, (11)Oregon State University, Forest Engineering, Resources and Management, Corvallis, OR, United States, (12)University of Florida, Gainesville, FL, United States
The US Southeast is dominated by forested ecosystems, of which nearly 85 million hectares are timberland. These forests account for more than 1/3 (~12 Pg C) of the conterminous US forest C stocks and sequester 76 Tg C annually, equivalent to 13% of the regions greenhouse gas emissions. Additionally, these forests store a substantial amount of soil organic carbon (SOC), commonly exceeding twice the carbon measured in above ground biomass. However, due to the spatial-variation of SOC, these estimates have a large degree of uncertainty.

Current projections for the region indicate a likely warmer and dryer future climate. As such, typical recurring questions are: “How vulnerable are these carbon stocks to altered climate conditions?” and “How will we measure this change without accurate baseline estimates?”

To answer these questions, PINEMAP (Pine Integrated Network: Education, Mitigation, and Adaptation Project) established a multi-tiered monitoring network to provide baseline measurements for carbon, water, and nutrient storage and fluxes in forested ecosystems across the Southeastern US. Here, we present preliminary findings from a region-wide modeling approach in an attempt to understand how various scenarios of climate change may affect carbon stocks in these ecosystems. To achieve this, the DayCent biogeochemical model was parameterized and calibrated with site-specific data from the PINEMAP Tier 3 network. Preliminary results indicate the model performed well, with an R2 = 0.86 for simulated vs observed SOC and R2 = 0.97 for simulated vs observed net primary productivity (NPP). The model is currently being scaled up to the Tier 2 network, which consists of 324 plots, to provide more representative estimates across the entire Southeastern US. The results of this transdisciplinary research project will be used to improve decisions regarding management and carbon sequestration strategies.