Radial growth response of Pinus tabulaeformis to temperature during the growth season in southeastern Gansu, China

ABSTRACT Tree-ring chronologies of Pinus tabulaeformis from three sampling sites in southeastern Gansu Province in China and growth-related parameters calculated from daily average temperatures were utilized to explore the response features of tree radial growth to onset and cessation date, duration and accumulated temperature. The results indicated that the three chronologies exhibited a significantly positive correlation with the temperature (12°C) of the onset date (p<0.05), which is consistent with the initial threshold temperature that occurred in May based on radial growth monitoring nearby. The tree-ring chronology from the Taihe Mountains located in a relatively more arid area had a significantly negative correlation with cessation dates in late September with temperatures of 12.5-13.5°C (p<0.05). The threshold associated with the duration and accumulated temperature in the two chronologies from the Taihe and Xiaolong Mountains occurred at 12°C (p<0.01). Significantly negative correlations were found between the chronology from the Guiqing Mountains and accumulated temperature from 5°C to 15°C (p<0.05). Soil moisture stress caused by increasing temperatures and accumulated temperatures during the main growing season from May to September is the main limiting factor for the radial growth of trees. Our results are consistent with findings based on monthly climate data and tree-ring width indexes, indicating that the current research is reliable and effective.