Shuguang Liu is a Distinguished Professor at the School of Ecology, Hainan University, China. Formerly, Senior Research Ecologist at USGS Earth Resources Observation and Science (EROS) Center. He is globally recognized for pioneering biogeochemical cycle modeling and carbon cycle science: developing the General Ensemble Biogeochemical Modeling System (GEMS) applied worldwide for ecosystem dynamics research; leading the national assessment of carbon sequestration capacity and greenhouse gas mitigation potential across all U.S. ecosystems (2000-2050) under the Energy Independence and Security Act; discovering with the Chinese Academy of Sciences that mature forest soils can accumulate carbon. He has published 300+ professional papers including SCIENCE, PNAS, and Nature family journals (Google Scholar Citations > 20,000). Recognitions include Reuters' Top 1000 Most Influential Climate Scientists Globally and Stanford University's World Top 2% Scientists.
Vegetation growth is affected by past growth rates and climate variability. However, the impacts of vegetation growth carryover (VGC; biotic) and lagged climatic effects (LCE; abiotic) on tree stem radial growth may be decoupled from photosynthetic capacity, as higher photosynthesis does not always translate into greater growth. To assess the interaction of tree-species level VGC and LCE with ecosystem-scale photosynthetic processes, we utilized tree-ring width (TRW) data for three tree species: Castanopsis eyrei (CE), Castanea henryi (CH, Chinese chinquapin), and Liquidambar formosana (LF, Chinese sweet gum), along with satellite-based data on canopy greenness (EVI, enhanced vegetation index), leaf area index (LAI), and gross primary productivity (GPP). We used vector autoregressive models, impulse response functions, and forecast error variance decomposition to analyze the duration, intensity, and drivers of VGC and LCE in response to precipitation, temperature, and sunshine duration. The results showed that at the tree-species level, VGC in TRW was strongest in the first year, with an average 77% reduction in response intensity by the fourth year. VGC and LCE exhibited species-specific patterns; compared to CE and CH (diffuse-porous species), LF (ring-porous species) exhibited stronger VGC but weaker LCE. For photosynthetic capacity at the ecosystem scale (EVI, LAI, and GPP), VGC and LCE occurred within 96 days. Our study demonstrates that VGC effects play a dominant role in vegetation function and productivity, and that vegetation responses to previous growth states are decoupled from climatic variability. Additionally, we discovered the possibility for tree-ring growth to be decoupled from canopy condition. Investigating VGC and LCE of multiple indicators of vegetation growth at multiple scales has the potential to improve the accuracy of terrestrial global change models.