• 1.We monitored carbon fluxes of four typical forest ecosystems across China (tropical rainforest, subtropical evergreen broadleaf forest, temperate deciduous broadleaf forest, artificial plantation) via eddy covariance towers during 2011-2021, quantifying their net ecosystem exchange (NEE), ecosystem respiration (Reco) and gross primary productivity (GPP) with clear spatial differentiation. • 2.Forest carbon sequestration capacity in China shows a distinct latitudinal gradient, decreasing with rising latitude; the Xishuangbanna tropical rainforest has the strongest capacity, while the Hebei Yanshan artificial plantation has the lowest • 3.Air temperature and solar radiation (net radiation, photosynthetically active radiation, total radiation) are the dominant drivers of forest carbon fluxes nationwide, with Ta and Rn explaining over 65% of GPP variation; Reco is only positively correlated with air temperature and total radiation (p<0.001). • 4.Site-specific environmental controls on carbon fluxes are identified: tropical forests are sensitive to precipitation, subtropical forests to temperature and humidity, and high-latitude temperate forests (artificial and deciduous broadleaf) are primarily limited by temperature, with soil water content inhibiting Reco. • 5.Tropical and subtropical forests maintain stable interannual carbon flux variability, while temperate deciduous forests show greater fluctuations; artificial plantations have lower carbon sink efficiency than natural forests due to simplified species composition and low biodiversity. • 6.The findings provide empirical data for global carbon cycle models and scientific support for China’s dual carbon goals, proposing targeted forest management strategies for different climatic zones (e.g., protecting tropical/subtropical forests,optimizing northern artificial plantations). As a core component of terrestrial ecosystems, forests play critical roles in regulating the carbon cycle. To examine the spatiotemporal variations and factors that drive carbon fluxes across Chinese forests, we observed carbon fluxes using eddy covariance towers in four representative sites: Xishuangbanna (tropical rainforest), Jinfeng Mountain (subtropical evergreen broadleaf forest), Hebei Yanshan (artificial plantation), and Mao'ershan (deciduous broadleaf forest). The data were collected between 2011 and 2021 during one- to five-year intervals. Results showed that (1) Net ecosystem exchange (NEE) was -580 g Cm -2 a -1 in Xishuangbanna, -320 g Cm -2 a -1 in Jinfeng Mountain, -205 g Cm -2 a -1 in Hebei Yanshan, and -410 g Cm -2 a -1 in Mao’ershan. The ecosystem respiration (R eco ) was 2450 g Cm -2 a -1 , 1780 g Cm -2 a -1 , 1215 g Cm -2 a -1 , and 1650 g Cm -2 a -1 , respectively. (2) Gross primary productivity (GPP) was 3030 g Cm -2 a -1 (primary forest), 2100 g Cm -2 a -1 (secondary forest), 1430 g Cm -2 a -1 (reforested forest), and 2030 g Cm -2 a -1 (artificial forest). Carbon sequestration capacity generally decreased as latitude increased, and artificial plantations exhibited the lowest capacity. (3) The primary environmental factors driving carbon fluxes were air temperature and solar radiation. Air temperature, net radiation, photosynthetically active radiation, and total radiation were all positively correlated (p<0.001) with ecosystem carbon productivity and GPP, while only air temperature and total radiation were positively correlated with R eco (p<0.001). These findings highlight the importance of long-term monitoring for tracking changes in forest carbon stocks. These data are crucial for predicting feedbacks to regional and global carbon cycles and informing climate policy.
LV et al. (Fri,) studied this question.