Potential reduction in carbon fixation capacity under climate change in a Pinus koraiensis forest

Abstract

There has been an increasing recognition of the crucial role of forests, responsible for sequestering atmospheric CO₂, as a moral imperative for mitigating the pace of climate change. The complexity of evaluating climate change impacts on forest carbon and water dynamics lies in the diverse acclimations of forests to changing environments. In this study, we assessed two of the most common acclimation traits, namely leaf area index and the maximum rate of carboxylation (V_cmax), to explore the potential acclimation pathways of Pinus koraiensis under climate change. We used a mechanistic and process-based ecohydrological model applied to a P. koraiensis forest in Mt. Taehwa, South Korea. We conducted numerical investigations into the impacts of (i) Shared Socioeconomic Pathways 2–4.5 (SSP2-4.5) and 5–8.5 (SSP5-8.5), (ii) elevated atmospheric CO₂ and temperature, and (iii) acclimations of leaf area index and V_cmax on the carbon and water dynamics of P. koraiensis. We found that there was a reduction in net primary productivity (NPP) under the SSP2-4.5 scenario, but not under SSP5-8.5, compared to the baseline, due to an imbalance between increases in atmospheric CO₂ and temperature. A decrease in leaf area index and an increase in V_cmax of P. koraiensis were expected if acclimations were made to reduce its leaf temperature. Under such acclimation pathways, it would be expected that the well-known CO₂ fertilizer effects on NPP would be attenuated.