The study of Freezing Fluctuations and its Application in the Function of Nuts Production in Ahar Township

The purpose of this research was studying the variation of frost phenomenon and applications of their results in grape, walnut, mulberry and almond production in Ahar in North West Iran. We gathered daily minimum air temperature records of Ahar areafrom 1986 to 2005 along with fruit production dates. Initially we distinguished 4 detrimental temperature ranges of A, B, C, D and adapted frost days with Julian day-numbers. We calculated parameters and variables such as normal distribution, t distribution and Pearson correlation coefficient, standing average departure index, variations of frost occurrence dates, durations of growth season and the minimumdaily temperature all of which influence fruit production. Some of the important results of this research are as follows: If B occurred earlierit will be harmful for grape production. On the other hand, if the last spring frost occurs lately, grape production rates might increase. The effect of last spring frost on walnut is higher than the first summerfrost damages. The variation in mulberry production living during 1-15 May could get it away from frost damage.