关键词: 坡向, 辽东栎, 径向生长, 气候变化

Abstract: Slope aspect determines the allocation of water and heat resources, thereby influencing tree growth. Investigation of the radial growth of Quercus wutaishanica across different slope aspects provides valuable insights for the sustainable management and conservation of natural Q. wutaishanica forests. Based on the dendrochronology method, we drilled tree core samples of Q. wutaishanica on three distinct slopes (shady, semi-shady, and semi-sunny) in the Qiuqianjia Forest Farm of the Liupanshan Mountains. We constructed tree-ring width chronologies and basal area increment (BAI) series on the three slopes and analyzed the radial growth trends of Q. wutaishanica across different slopes and their responses to climate change. The results showed that climate had become warmer and drier from 1974 to 2020. The mean annual temperature underwent a significant abrupt shift in 1998, while there were no significant abrupt shift points for mean annual rainfall and average annual standardized precipitation evapotranspiration index (SPEI). Following the abrupt shift of temperature (1998-2020), the radial growth of Q. wutaishanica declined in all slope aspects, with the semi-sunny slope exhibiting the most significant decline. Both the tree-ring width index and BAI exhibited a significant downward trend (P<0.05). Temperature in May, rainfall in current spring (March-May), and SPEI in current summer (June-August) had the most significant impact on tree growth (P<0.05). Among the three slopes, temperature in May showed the strongest negative correlation with the shady slope and the weakest negative correlation with the semi-sunny slope. Conversely, spring rainfall and summer SPEI exhibited the strongest positive correlations with the semi-sunny slope and the weakest positive correlations with the shady slope. Before and after the abrupt shift of temperature (1998), spring rainfall and summer drought stress were the primary limiting factors for radial growth. These findings suggest that warming-induced drought stress has significantly constrained the radial growth of Q. wutaishanica. Among the three slope aspects, the radial growth of Q. wutaishanica on the semi-sunny slope exhibited the most pronounced decline, and was the most sensitive to climatic factors, with the greatest risk of further decline. In conclusion, this study underscores the critical role of slope aspect in shaping the climate-growth relationships of Q. wutaishanica, especially in the context of warming-induced drought stress. Future forest management and conservation strategies in the Liupanshan Mountains should prioritize the protection of Q. wutaishanica forests on semi-sunny slopes.

Key words: slope aspect, Quercus wutaishanica, radial growth, climate change