Abstract:

[Objective] This study aimed to systematically elucidate the spatiotemporal evolution patterns of carbon sequestration capacity, its topographic differentiation, and the contributions of climatic drivers in the Northeast Forest Region of China. [Methods] Using meteorological and remote sensing data, with net ecosystem productivity (NEP) as the core indicator, we integrated spatial clustering, partial correlation analysis, and multiple correlation analysis and incorporated topographic factors, including terrain relief, elevation, and slope. [Results] 1) The annual mean NEP across the forest region was 301.2 g·m^-2. A total of 92.2% of the forest area showed an increasing trend in carbon sequestration capacity, although considerable interannual variability was observed. Specifically, 58.2% of the area exhibited low stability. Carbon sequestration capacity showed a decreasing latitudinal gradient, characterized by a “high in the southeast and low in the northwest” pattern. 2) Significant spatial autocorrelation was detected, with high-value clusters (40.3%) and low-value clusters (41.3%) forming a distinct “high in the east, low in the west” spatial pattern. 3) Topography exerted significant regulatory effects. Carbon sequestration capacity, stability, and the proportion of high-value cluster areas all increased with increasing terrain relief and slope, but decreased with elevation. Moreover, the rate of change in carbon sequestration exhibited a unimodal response to gradients of terrain relief and elevation, initially increasing and then decreasing. 4) Climatic factors influenced carbon sequestration across 42.6% of the forest area. Precipitation was the most widespread climate driver (18.0%), mainly affecting eastern Inner Mongolia and southeastern Heilongjiang. The influence of climatic drivers strengthened with increasing terrain complexity, including greater relief, higher elevation, and steeper slopes. [Conclusion] Carbon sequestration capacity in the Northeast Forest Region shows a distinct decreasing latitudinal gradient and strong spatial clustering. Topography plays a significant regulatory role, precipitation is the primary climatic driver, and climatic influences are amplified under more complex terrain conditions. These findings provide a scientific basis for accurately assessing forest carbon sinks and implementing differentiated ecological management in regions with complex topography.

Key words: carbon sequestration capacity, spatio-temporal heterogeneity, driving factors, climate change, net ecosystem productivity

摘要：

【目的】旨在系统揭示东北林区固碳能力的时空演变格局和地形分异特征，并定量识别气候因子的驱动作用。【方法】利用气象和遥感数据，基于净生态系统生产力（NEP）指标，结合空间聚类、偏相关分析与复相关分析，引入地形地貌因子，对东北林区进行研究。【结果】1）林区NEP年均值为301.2 g·m^-2，92.2%的林区呈增加趋势，但年际波动较大，58.2%的林区稳定性偏低；固碳能力呈“东南高、西北低”的纬向递减格局。2）固碳能力呈显著空间自相关性，高值聚类区（40.3%）与低值聚类区（41.3%）形成“东高西低”集聚格局。3）地形调控效应显著，固碳能力、稳定性及高值聚类面积占比随地势起伏和坡度增加而增大，随海拔升高而减小；固碳变化速率随地势起伏和海拔增加呈先升后降的单峰模式。4）气候因子驱动的面积占比为42.6%，其中降水驱动最广（18.0%），主要分布于内蒙古东部和黑龙江东南部。气象驱动作用随地形的复杂化（地势起伏、海拔与坡度增加）而增强。【结论】东北林区固碳能力呈纬向递减格局且空间集聚明显，地形对固碳分布具有显著调控效应，降水为主要气候驱动因子，且地形复杂化会增强气候影响。上述结果可为复杂地形区的森林碳汇精准评估与差异化生态管理提供了科学依据。

关键词: 固碳能力, 时空异质性, 驱动因素, 气候变化, 净生态系统生产力