Response of the relationship between Pinus tabuliformis Carr. radial growth and climatic factors to abrupt changes in temperature in Qinling Zhen'an

Using Pinus tabuliformis Carr. samples obtained in the Muwang National Forest Park in Zhen'an, Shaanxi, we studied the relationship between radial growth of P. tabuliformis and climatic factors using response functions, moving correlation analysis, and other dendrochronological methods. We further explored the response of this relationship to climate change. Results showed that: (1)Based on the Mann-Kendall test, average temperature in the study area exhibited a significant abrupt change in 1989, with temperatures 1.4℃ higher than before the change. (2) Based on statistical analysis of standard chronology, the average tree-ring index (1.04) after the abrupt temperature change was significantly greater than the index (0.87) before the change, indicating that the increase in temperature was beneficial for P. tabuliformis growth. (3) Correlation analysis showed that the temperature demands of P. tabuliformis run throughout the entire growing season. The temperature, especially in March and April, had a positive effect on P. tabuliformis growth. The temperature from the previous November also had an effect on matter accumulation in P. tabuliformis. Precipitation was not the major limiting factor for growth, but moderate precipitation in February had a positive effect on radial growth. (4) Precipitation in February and average temperatures in March and April maintained a stable positive correlation with P. tabuliformis in the study area; the relationship between radial growth of the trees and climatic factors fluctuated in the other months. Based on the above results, fluctuations in the tree growth-climate relationship over time should be considered when carrying out regional climate reconstruction research.