1Associate Prof, Department of Geography Yazd University, Yazd, Iran
2M.Sc, Yazd University and Chaharmahal & Bakhtyari Metrological Office’s Expert, Shahrekord, Iran
Objective: An increasing number of studies have reported on shifts in timing and length of the growing season, based on phonological, satellite and climatologically studies. Changes in the timing and length of the growing season (GSL) may not only have far reaching consequences for plant and animal ecosystems, but persistent increases in GSL may lead to long-term increases in carbon storage and changes in vegetation cover which may affect the climate system. With the aim of these study is an investigation the trend of time changes of starts and end season growing length in west of Iran. Methods: This investigation has presented 49 years inputs of temperature from 8 synoptic stations in west of Iran. Homogenize the series using run-test experiment were determined and accomplished in the way of auto regression from rebuilding of missed data by way of man-Kendal test the randomness of data was examined and the series that had change or trend with %5 confidence interval were recognized then with graphically man-Kendal test and moving mean of 5 year, circumstances and the start time of trend or changes were determined and the values of changes were calculated. Results: The results show more changes in series associating with start and end of temperatures.