The influence of disturbance and conservation management on the greenhouse gas budgets of China's forests

摘要

Diseases, pests, and rats (DPR), forest fires and harvesting have been identified as critical disturbance factors that influence the carbon (C) cycle of forest ecosystems. In addition, forest conservation management, i.e., fire and DPR control, and reductions in wood production could increase C sequestration and reduce emissions. However, the offsets or promotion effects of greenhouse gas (GHG) budgets resulting from these factors on forest biomass C sinks remain unknown in China. Using the carbon accounting and net mitigation of forest (CANM-Forest) methodology, we assessed the GHG budgets of disturbances and conservation management in China from 2000 to 2014. The objective of our study was to determine the main emissions factors, analyze the effective mitigation strategies, and clarify the offsets or promotion of these activities in relation to the Chinese forest biomass C sink. The results indicated that disturbances released 64.9 Tg Ce yr(-1) and offset 32.1% of the forest biomass C sink, which was estimated based on national forest resource inventories. Harvesting was a major contributor to national GHG emissions, while the main driving factor of regional GHG emissions varied. Furthermore, conservation management significantly mitigated 27.3 Tg Ce yr(-1) emissions and enhanced the net biomass C sink by 24.3%, indicated that 24.3% of the Chinese forest's biomass C sink was attributed to conservation management. Fire control dominated promotion effects in the national forests, and the main enhanced factor of the regional forest's biomass C sink varied. Proper forest conservation management should be implemented in accordance with the specific conditions of regional forests to increase contributions to GHG mitigation. Our study provided a forest C accounting for China and indicated that simulations of natural and human disturbances, together with forest management, could provide insights into mitigation options and sustainable forest management for policymakers. (C) 2020 Published by Elsevier Ltd.