Khanal Shiva, Nolan Rachael H, Medlyn Belinda E, Boer Matthias M
Forest Research and Training Center Kathmandu Nepal.
Hawkesbury Institute for the Environment Western Sydney University Richmond New South Wales Australia.
Ecol Evol. 2024 Jun 18;14(6):e11517. doi: 10.1002/ece3.11517. eCollection 2024 Jun.
Understanding the biophysical limitations on forest carbon across diverse ecological regions is crucial for accurately assessing and managing forest carbon stocks. This study investigates the role of climate and disturbance on the spatial variation of two key forest carbon pools: aboveground carbon (AGC) and soil organic carbon (SOC). Using plot-level carbon pool estimates from Nepal's national forest inventory and structural equation modelling, we explore the relationship of forest carbon stocks to broad-scale climatic water and energy availability and fine-scale terrain and disturbance. The forest AGC and SOC models explained 25% and 59% of the observed spatial variation in forest AGC and SOC, respectively. Among the evaluated variables, disturbance exhibited the strongest negative correlation with AGC, while the availability of climatic energy demonstrated the strongest negative correlation with SOC. Disturbances such as selective logging and firewood collection result in immediate forest carbon loss, while soil carbon changes take longer to respond. The lower decomposition rates in the high-elevation region, due to lower temperatures, preserve organic matter and contribute to the high SOC stocks observed there. These results highlight the critical role of climate and disturbance regimes in shaping landscape patterns of forest carbon stocks. Understanding the underlying drivers of these patterns is crucial for forest carbon management and conservation across diverse ecological zones including the Central Himalayas.
了解不同生态区域森林碳的生物物理限制对于准确评估和管理森林碳储量至关重要。本研究调查了气候和干扰对两个关键森林碳库空间变异的作用：地上碳（AGC）和土壤有机碳（SOC）。利用尼泊尔国家森林资源清查的样地水平碳库估计值和结构方程模型，我们探讨了森林碳储量与大尺度气候水热可利用性以及小尺度地形和干扰之间的关系。森林AGC和SOC模型分别解释了森林AGC和SOC观测到的空间变异的25%和59%。在评估的变量中，干扰与AGC呈现出最强的负相关，而气候能量可利用性与SOC呈现出最强的负相关。选择性采伐和薪柴采集等干扰会导致森林碳立即损失，而土壤碳变化的响应时间更长。由于温度较低，高海拔地区较低的分解速率保存了有机质，并导致该地区观测到较高的SOC储量。这些结果凸显了气候和干扰状况在塑造森林碳储量景观格局中的关键作用。了解这些格局的潜在驱动因素对于包括喜马拉雅中部在内的不同生态区域的森林碳管理和保护至关重要。
