Protected areas enhance long-term carbon sequestrations in China’s forests

Abstract Protected areas (PAs) serve as critical refugia for forests, helping to maintain ecosystem integrity and carbon (C) sequestration. However, the extent to which the additional C sequestration benefits of protection persist as forests recover remains poorly understood. Here, we coupled a Forest Carbon Sequestration Model with propensity score matching to quantify the spatiotemporal dynamics of C sequestration gains in China’s strictly protected forests. Our analysis covered more than 10 million ha of protected forests over a 70-year period. The carbon sequestration rate (CSR) of protected forests is projected to increase initially, but age-related constraints are expected to intensify as stands mature. Accordingly, the proportion of PA forests with declining CSR is projected to increase from approximately 13% in 2010 to more than 90% by 2035. Counterfactual estimates further indicate that the additional C sequestration attributable to protection will decline by an average of 0.19 t C ha⁻¹ yr⁻¹ between 2010 and 2060 across three emission scenarios, accompanied by a 46.8% decline in the proportion of PAs that sustain positive C sequestration gains. Nevertheless, 63.2% of matched PAs are projected to retain positive C sequestration gains, contributing an additional 51.9 Tg C by the 2060s and increasing C storage by 134% relative to matched unprotected forests. These findings show both the enhancement of protection strategies and the growing risk of age-related C sequestration saturation, posing a challenge to long-term climate stabilization efforts.