Guangxi Zhiwu (Sep 2023)
Radial growth of Pinus yunnanensis var. tenuifolia and its response to climatic factors in Jinzhongshan, Guangxi
Abstract
In order to explore the radial growth of Pinus yunnanensis var. tenuifolia in Jinzhongshan of Guangxi and its response to climate, a standard tree-ring chronology of P. yunnanensis var. tenuifolia was established, response analysis was used to explore the relationship between radial growth and climatic factors, and stepwise regression and variance decomposition were used to quantify the effects of climatic factors on radial growth of P. yunnanensis var. tenuifolia. The results were as follows: (1) Sunshine duration in January, August, September and November, and the mean minimum temperature and the mean temperature in October of the previous year were significantly positively correlated with tree-ring width of standard chronology. By contrast, there was a significant negative correlation between the number of days with the amount of precipitation >10 mm in June of the previous year and tree-ring width. Precipitation in February, relative air humidity and the mean minimum temperature in March, sunshine duration in June, and the mean maximum temperature and mean temperature in September of the current year were positively correlated with tree-ring width. (2) The variance decomposition results of the final stepwise regression model revealed that the mean minimum temperature in October of the previous year had the greatest effect on the radial growth of P. yunnanensis var. tenuifolia (explaining 23.35% of the variance), followed by the mean maximum temperature in September of the current year (explaining 10.39% of the variance). Sunshine duration in January and November of the previous year explained 3.94% and 6.58% of the variation in radial growth of P. yunnanensis var. tenuifolia, respectively. In conclusion, autumn temperature and winter light condition are the main climatic factors limiting the radial growth of P. yunnanensis var. tenuifolia in Jinzhongshan. In addition, both drought in early spring and heavy rainfall in rainy season can reduce the radial growth of P. yunnanensis var. tenuifolia.
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