Study on carbon source-sink patterns, carbon neutrality contribution, and management strategies in Lingnan National Park

Regarding global climate change, national parks serve as key pillars in the construction of ecological civilization and play a vital role in achieving carbon neutrality goals. Taking the Lingnan National Park as a case study, this study systematically evaluates its carbon source-sink dynamics, changes in carbon storage, and carbon neutrality status, aiming to clarify its carbon balance mechanisms and its contribution to regional carbon neutrality. By integrating field surveys with multi-source data analysis, carbon emissions from major sources were quantified, including energy activities, agricultural practices, waste treatment, and forest fires. Combined with forest resource surveys and field plot data, the study analyzes the carbon storage, carbon sink potential, and spatiotemporal variation characteristics of typical forest ecosystems. The main findings are as follows: (1) The total annual carbon emission amounts to 11.85×10⁴t CO₂-e, with an emission intensity per unit area of 0.61t CO₂-e/hm², which is lower than the average level of Guangdong Province. In the emission structure, agricultural activities dominate, accounting for 73.80% of total emissions, followed by energy activities (21.00%) and waste treatment (5.20%). No emissions from industrial activities or forest fires were recorded. (2) The total carbon stocks in 2017 and 2022 were 1570.05×10⁴t C and 1675.37×10⁴t C, showing an increasing trend across all carbon pools, with a net increase of 105.32×10⁴t C. Carbon density increased from 81.22t C/hm² to 86.67t C/hm². Natural forests exhibited significantly higher carbon density than planted vegetation. Areas with high carbon density were predominantly concentrated in coniferous-broadleaf mixed forests, coniferous mixed forests, and regions dominated by hardwoods, reaching as high as 97.82t C/hm². The spatial pattern displayed distinct vertical differentiation, gradually increasing from low-altitude plains to mid-altitude regions. (3) The average annual carbon sink was 77.23×10⁴t CO₂-e, with a carbon sequestration rate of 3.99t CO₂-e hm^-2 a^-1, surpassing both the Chinese and global forest averages and indicating a strong carbon sink system. Carbon sequestration capacities varied among dominant tree species, ranked as follows: hardwood forests > softwood forests > mixed forests ≫ economic forests. Notably, subtropical coniferous mixed forests, broadleaf forests, and evergreen broadleaf forests exhibited the highest carbon sequestration capacities. (4) The carbon sink significantly exceeded carbon emissions, demonstrating a synergistic feature of "low emissions and high carbon sink". The annual carbon sink surplus was 65.39×10⁴t CO₂-e, primarily contributed by the core protected area, highlighting its substantial role in supporting the carbon neutrality goals of northern Guangdong. In conclusion, this study proposes the establishment of a refined carbon budget monitoring system centered on national parks and natural reserves. By enhancing the protection of natural forests and implementing nature-based ecological restoration strategies for low-efficiency forests, biodiversity conservation can be synergistically strengthened alongside carbon sink services. The study recommends adopting a "conservation-restoration-regulation" triad strategy to enhance carbon sink capacity, thereby providing robust scientific support for achieving regional carbon neutrality goals.