Responses of radial growth of different tree species to abrupt temperature change in the northern Greater Khingan Mountains, China.

We constructed standardized chronologies of tree-ring width of <i>Larix gmelinii</i> and <i>Pinus sylvestris</i> var. <i>mongolica</i>, the main tree species in the Mangui region of the northern Greater Khingan Mountains based on dendrochronology methods, we explored the responses of radial growth of the two species to climate change. The results showed that the radial growth of <i>L. gmelinii</i> was mainly limited by temperature, which was significantly negatively related to mean temperature in October of the last year and that in March and May-August of the present year. The radial growth of <i>P. sylvestris</i> var. <i>mongolica</i> was promoted by both temperature and precipitation, which was significantly positively related to precipitation in May of the present year and temperature in October of the last year and May-September of the present year. We analyzed temperature data from 1960 to 2021 in the Mangui region using the Mann-Kendall test, and found that mean annual temperature of the region had a warming abrupt change in 1988. <i>L. gmelinii</i> radial growth showed a decreasing trend both before and after the abrupt temperature change, and the downward trend of its radial growth increased slightly after the abrupt change. Radial growth of <i>P. sylvestris</i> var. <i>mongolica</i> changed significantly, with a decreasing trend before the abrupt change and a significant increasing trend after the abrupt change. The response to temperature was enhanced after the abrupt change, with a remarkable positive relationship with the monthly average minimum temperature in May of the present year. The analysis of sliding relationship showed that the sensitivity of <i>L. gmelinii</i> radial growth to climatic factors changed first to increase and then to weaken, and that of <i>P. sylvestris</i> var. <i>mongolica</i> radial growth gradually increased.