关键词: 树种, 径向生长, 干旱响应, 生理策略

Abstract: Cunninghamia lanceolata and Quercus acutissima are common plantation species in the hilly regions of southern China. To understand the responses of radial growth to drought under the background of climate warming, we analyzed the radial growth and intrinsic water use efficiency (iWUE) of both species from 1968 to 2024, ecolo-gical resilience indices during the 1994-1995 drought event, and physiological strategies under the 2024 drought in Mopanshan Forest Farm, Jurong City, Jiangsu Province. Several variables related with dendrochronology and leaf physiological processes were measured. The results showed that: 1) The radial growth level of C. lanceolata was higher than that of Q. acutissima in the young forest stage (1973-1981), with the standard chronology index reaching a maximum of 1.7, after which it stabilized between 0.9 and 1.1, and was surpassed by Q. acutissima multiple times in the mature forest stage (after 2010). 2) In all the years except 1978, the iWUE of C. lanceolata was consistently higher than that of Q. acutissima. The sensitivity of radial growth and iWUE to climatic factors was higher in C. lanceolata than in Q. acutissima. The iWUE of C. lanceolata showed significant positive correlations with the mean temperature from the previous September-October and the current February-June, the mean maximum temperature from the previous September and the current February-April, as well as the annual mean minimum temperature, indicating that its iWUE was driven by rising temperature. 3) In historical drought events, the resistance of both species was less than 1 and recovery was greater than 1. The resilience of C. lanceolata was greater than 1 while that of Q. acutissima was less than 1, indicating that the ecological resilience of C. lanceolata was superior to that of Q. acutissima. 4) Under drought conditions, C. lanceolata sustained low stomatal conductance and transpiration rates to maintain stable photosynthesis, whereas Q. acutissima adopted a more aggressive physiological strategy, with photosynthetic rate declining rapidly under high temperatures and strong light at noon. In summary, C. lanceolata maintained stronger hydraulic safety and ecological resilience through a conservative water use strategy, while the aggressive strategy of Q. acutissima, increased drought risks. Water use strategy was the primary factor leading to the differences in radial growth and drought response between the two species.

Key words: tree species, radial growth, drought response, physiological strategy