Carbon Stock Differences Associated with Private Forest Land-Use Designation in South Korea

Private forest land-use designations can contribute to climate mitigation; however, their carbon benefits are difficult to estimate owing to differences in site and environmental conditions between protected and less strictly regulated forest lands. Evidence on whether designation-associated carbon differences vary with forest structure is also limited. We evaluated carbon stock differences between protected areas in private forests (PA) and matched semi-conservation mountainous districts (SCA) in South Korea using the InVEST Carbon Storage and Sequestration model. We used propensity score matching, ATT estimation, and matched-sample regression. Robustness checks examined alternative specifications. The model-estimated mean carbon stock was 4.97 Mg C ha−1 higher in PAs than in comparable SCAs (95% CI: 4.45–5.49, p < 0.001). The PA-SCA difference varied by forest structure; it was greater in broad-leaved forests than in coniferous forests, showing a nonlinear pattern across canopy density classes, and declining with increasing age class. Thus, we inferred that carbon stock differences associated with private forest land-use designation were structurally heterogeneous. Although our findings reflect cross-sectional associations, they provide evidence for differentiated land-management, compensation, and conservation prioritization strategies. An aboveground-only sensitivity check retained a positive PA-SCA association, although model-based contrasts varied by specification.