Differences in Rainfall Interception during the Growing and Non-growing Seasons in a Fraxinus rotundifolia Mill. Plantation Located in a Semiarid Climate

We estimated the rainfall interception loss (I), canopy storage capacity (S), the ratio of mean evaporation rate from the wet canopy () over the mean rainfall intensity () (mm h-۱) (), and free throughfall coefficient (p) in a Fraxinus rotundifolia Mill. stand located in an afforested Park land in a semiarid region of Iran. For each storm event, I was calculated as the gross rainfall (GR) minus throughfall (TF). S was estimated by indirect methods: the minimum, the mean, and the Gash and Morton. Fifty-five rainfall events were recorded (cumulative GR ۱۹۷.۲ mm), with ۳۱ events occurring during the growing season(total GR ۸۸.۰ mm) and ۲۴ events measured during the non-growing season (total GR ۱۰۹.۲ mm). The mean ratio of I to GR equalled ۳۹.۲% during the growing season vs. ۲۳.۹% during the non-growing season. For the growing season, S was estimated to be ۰.۲۷, ۰.۲۱, and ۰.۲۳ mm using the minimum, mean, and Gash and Morton methods, respectively. For the non-growing season, these values were estimated to be ۰.۱۷, ۰.۱۳, and ۰.۱۵ mm, respectively. During the growing and non-growing seasons,  were estimated to be ۰.۱۳ and ۰.۱۱, respectively, with the corresponding p values of ۰.۳۹ and ۰.۵۲. The loss of the leaves resulted in decline in I, S, and, and increase in p. For semiarid regions, these values are useful for solving some water management problems.

Keywords:

Canopy storage capacity , Free throughfall coefficient , Seasonal variability