Investigation of Climate Variables (Temperature and Precipitation) Effects on Populus alba Annual Growth

Fast-growing tree species such as poplar have important role in supplying raw wood materials. The main purpose of present study was to evaluate the impact of climate variables (namely temperature and rainfall) on poplar growth. Samples were collected using increment borer from poplar trees around city of Sari, Iran. Ten samples were extracted and then prepared for measuring and analyses. Tree ring widths were measured by Corel Draw 10 graphical program and using dendrochronological methods analysis. Time series span were recorded 27 years (1982-2008). Quality and measuring control were performed using COFFECHA and computed tree ring index by ARSTAN program. Analysis showed that sensitivity is 25% and correlation coefficient between trees was 50%. Comparing the tree ring index with annually recorded climate variables showed that increasing of temperature in July had negative effects on annual growth. In addition, rainfall in April had positive effects on annual growth of poplar trees. Finally, it is to be noted that poplar is a sensitive tree to high temperature and its growth is decreased in dry condition.