关键词: 树轮宽度, 气温突变, 种间, 种内, 响应差异

Abstract: Aims This study investigated the differential climatic responses of Larix gmelinii (Xing'an larch) and Pinus sylvestris var. mongolica (Mongolian pine) in the Greater Khingan Range at two spatial scales—interspecific (same longitude and latitude) and intraspecific (same longitude, different latitudes)—with the aim of elucidating the shifts in dominant limiting factors of radial growth under climate warming and their implications for carbon sink management. Methods A total of 159 tree cores were collected from Larix gmelinii at the Alongshan Forest Farm (ALS), Larix gmelinii at the Chaihe National Nature Reserve (CHL), and Pinus sylvestris var. mongolica at the Honghua'erjibartu Forest Farm (BRT). Tree-ring width standard chronologies were developed using dendrochronological methods. Findings (1) At the interspecific level, CHL exhibited a highly significant negative correlation with March maximum temperature and a significant negative correlation with March minimum temperature, while BRT showed a significant positive correlation, indicating opposite response strategies between the two species. (2) At the intraspecific level, ALS displayed a significant positive correlation with spring (February–April) temperatures, whereas CHL showed a significant negative correlation, suggesting a divergence in dominant limiting factors associated with latitudinal position. (3) Following an abrupt warming event in 1988, the tree-ring index of ALS increased by 116.8%, shifting from a highly significant decline to a non-significant decline; the index of BRT increased by 19.1%, shifting from a highly significant decline to a highly significant increase; while both the index and growth trend of CHL remained relatively stable. Precipitation in the previous November promoted growth at BRT, whereas precipitation in April of the current year promoted growth at ALS. (4) Moving correlation analysis revealed that the sensitivity of radial growth to temperature gradually decreased for ALS and BRT, while the sensitivity of CHL to climatic factors gradually increased. Conclusion The interspecific differences stem from the fundamental contrast between the "risk-averse, conservative" strategy of larch and the "opportunistic" strategy of Mongolian pine. Based on a comparison of two larch sites—one northern (ALS) and one southern (CHL)—preliminary evidence suggests that intraspecific differences may reflect a potential shift in dominant limiting factors from temperature limitation to water limitation associated with latitudinal position; however, this trend requires further validation with additional sites at intermediate latitudes. Climate warming is reshaping the forest dynamics of the Greater Khingan Range: larch in permafrost zones exhibits a short-term "warming-induced growth enhancement," while Mongolian pine, with its greater adaptability, may gain a competitive advantage in the future, potentially contributing to the long-term stability of the regional carbon sink. This study provides a scientific basis for adaptive forest management and carbon sink strategies in cold-temperate forests under climate change.

Key words: Tree ring width, abrupt temperature change, interspecific, intraspecific, response variation