Warming-induced suppression of CO2 fertilization in high-elevation Qinghai spruce of the northeastern Tibetan Plateau - Yarong Qin; Liang Jiao; Zhengdong Guo; Qian Li; Ruhong Xue; Peng Zhang; Xuge Wang; Kuan Zhang; Le Zhang; Xueya Cai (Agricultural and Forest Meteorology, 2026)