Maximum Gross Primary Productivity Dominates the Trend in Gross Primary Productivity in China’s Deciduous Forest Ecosystems

The terrestrial gross primary productivity (GPP) has increased over the past two decades. However, climatic attribution and physiological phenological processes that control trends in GPP are still unclear. Here, we used remote-sensing-based vegetation phenology datasets, analyzed spatial temporal variation GPP, investigated influence of growing season length (GSL) maximum value (GPPmax) on annual quantified effect climate variables GPP. Our results identified a significant increase (11.97 gC/m2/yr) during 2001–2020 China’s deciduous forest. GPPmax trend dominated when compared with GSL. Moreover, warming summer contributes to GPPmax, while extension GSL is primarily due temperature rise spring. planted forest showed higher increasing rate than natural forest, enhancement high sensitivity factors findings provide new perspective causes emphasize importance capturing variability modeling