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.

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.

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.

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.