Variations of deep water uptake and water use efficiency indicated divergence in tree growth stability

•Tree growth variability exhibits temporally increasing trend, with higher increasing rates in drier regions;•Aridity gradient drives the variations in the water use sources, wood density and leaf water use efficiency of Chinese pine;•Water uptake from deep soil layers and leaf water use efficiency were the two most important ecohydrological-related factors regulating tree growth stability beyond the climate factors.