Abstract:In order to quantify and separate the effects of key climatic factors on the radial growth at different altitudes in Altay Mountains of Xinjiang, China, the correlation analysis and multivariate linear regression analysis between the standard chronologies of Siberian larch (Larix sibirica), at high-, mid-and low-altitude stands, and climate factors were studied. The absolute and relative importance of different climate factors in the linear model were further calculated. The results showed that the radial growth of trees were significantly correlated with the current-June temperature (positive) and last-July precipitation (negative) at high altitude, which explain 33.1% of the total variance in tree radial growth and the relative contribution rate was 66.2% and 33.8%, respectively. The radial growth of trees were significantly correlated with the current-June temperature (positive) and last-June precipitation (negative) at mid-altitude, which explain 26.8% of the total variance in tree radial growth and the relative contribution rate was 40.1% and 59.9%, respectively. The radial growth of trees were significantly correlated with the last-June temperature (negative) and last-July precipitation (positive) at low altitude, which explain 29.4% of the total variance in tree radial growth and the relative contribution rate was 31.9% and 68.1%, respectively. So, it was suggested that the main climatic factors affecting the radial growth in Altay Mountains varies with altitude. The temperature and precipitation were the main limiting factors at high and low altitude, respectively.