Differences in ecological resilience of radial growth between and after drought.

To understand the responses of radial growth to climatic factors and the differences in ecological resilience to drought between a heliophilous species and a shade species in mixed forests, we developed the tree-ring width chronologies of and in three mixed forests based on the samples collected from Toudaogou of Saihanba in Hebei, Ningwu County and Kelan County in Shanxi Province. We analyzed the correlation between climatic factors and various chronologies and examined the differences in resistance (), recovery (), and resilience () of and in response to drought stress. The results showed that the radial growth of and was negatively correlated with the mean and maximum air temperature from May to July in three mixed forests, and was positively correlated with the Palmer drought index (PDSI) from May to September. Radial growth decline in trees due to drought stress was significantly different between the two species among the three sites, indicating different physiological and ecological regulation strategies. The resistance of was stronger than that of at the three study sites, with stronger resilience and resilient elasticity of than . As a result, exhibited greater drought resistance than . Under global warming condition, might be at greater risk of growth decline than in this region.