Growth of Pinus koraiensis and Its Response to Temperature Change at Changbai Mountain, Northeast China
长白山红松生长量及其对温度变化的响应

For tree species distributed across wide elevation gradients and playing vital roles in local ecosystems, the altitudinal variation of growth conditions may be of great importance for sustainable forest management. Dendrochronological analysis has been used widely to study the responses of tree-ring growth to climate in forests. Pinus koraiensis is a common coniferous species on Changbai Mountain and is economically important in northeastern China; however, little information is available on quantitative stem volumes and its climatic response. Here, we studied tree growth responses to temperature changes through the relationship between volumes of P. koraiensis and climate factors at Changbai Mountain. Based on tree ring data along an elevation gradient on the northern slope of Changbai Mountain, Jilin province, the volumes of P. koraiensis from 1958-2007 were obtained using allometric methods. Pinus koraiensis volumes were compared to historical climate data to document how growth has responded to temperature variation from 1958-2007. The results show that tree growth increased significantly from 1958-2007 at three study sites and the annual mean volume at CBS2 site is much higher than that of the other two sites. Soil moisture condition was good through most years for Changbai Mountain so we mainly focused on the impact of the temperature. Tree growth was positively correlated with spring temperature, the growing season temperature, prior winter temperature and pre-growing season temperature. Partial correlation analysis suggest the relationship between growth and the growing season temperature was rather strong when the effects of temperature in other seasons were controlled. Overall, tree growth was greatly limited by the growing season temperature along the entire slope. A growing season temperature around 15~16.5°C is favorable for tree growth. We believe that this threshold is mainly due to the enhanced leaf area and the photosynthetic rate of trees. There was substantial variability in response to temperature variation across different study sites. The variance in P. koraiensis growth explained by growing season temperatures were 32%, 41%, and 37% for CBS1, CBS2, and CBS3. Volumes increased by 3.06 dm3/tree, 9.18 dm3/tree, and 6.44 dm3/tree with each 1° C increase in temperature at CBS1, CBS2, and CBS3 respectively. These different responses should be taken into account when considering the effects of global change on trees.