Climate change has had a significant impact on forest ecosystem. Pinus koraiensis is one of precious tree species in Northeast China. The coniferous and broadleaved mixed forest dominated by pine is the representative vegetation type in XiaoXing'AnLing of China. Under the climate change background, studying the response of the growth of Pinus koraiensis to climate change is important to understand the climate change impact on forest ecosystem. Simulation models as effective tools for assessing the climate change impact have been applied widely in different regions over the world. A process-based ecological mechanism model (TREE-RING) had been verified for simulating the radial growth of Pinus koraiensis in XiaoXing'AnLing of China. The results showed that simulated phenology was well coincident with observed phenology. There was a high correlation between simulated and observed cell series of Pinus koraiensis. Based on the validated TREE-RING model, the study simulated the growth trend of Pinus koraiensis in XiaoXing'AnLing under future climate scenarios and explored the response mechanism of tree growth to climate change, which is helpful to understand climate change impact, alleviate the negative effects of climate changes on tree growth and provide references for policy-making related to addressing the climate change.
For this study, we intend to use TREE-RING model to simulate the growth of Pinus koraiensis in the XiaoXing'AnLing based on a middle medium emissions climate change scenario (SRES A1B) generated by global climate model (MPI_ECHAM5) from 1961 to 2060. The meteorological data including daily maximum temperature, daily minimum temperature and daily precipitation with the resolution of 1°×1° was interpolated to Yichun meteorological station (47°73'N,128°92'E,240.9 m.a.s.l) with the method of Bilinear interpolation. The analysis on the variation characteristics of climate factors from 1961 to 2060 showed that atmospheric CO₂ concentration will continue to increase and reach 563 mg/L in 2060. Maximum and minimum temperature will have a fluctuating rising tendency while precipitation will change slightly.
TREE-RING droved by climate data model was run for 100 years from 1961 to 2060. The simulated results showed that under the SRES A1B emission scenarios, with the increase in atmospheric CO₂ concentration and air temperature, the beginning and end dates of Pinus koraiensis growth will advance significantly in the XiaoXing'AnLing from 2011 to 2060 with a mean advance of 5 days in the beginning date and 3 days in the end date compared with 1961-2010. Annual radial growth period will prolong by about 2 days in the future fifty years. The radial growth rate will be increased by 35% in 2011-2060 compared with 1961-2010, which is mainly due to the effect of CO₂ fertilization. The individual change in precipitation will increase tree radial growth by about 2% while the individual change in air temperature will decrease tree radial growth by 23%. Sensitivity analyses were performed to see the response of the model under variable climatic environmental conditions. The results show that rising air temperature in spring (March and April) increases tree growth rate significantly, however, rising air temperature in summer (June-August) decreases tree growth rate when air temperature was increased by 1℃ and CO₂ concentration and precipitation were not changed.