Differences in rainfall interception during the growing and non-growing seasons in a Fraxinus rotundifolia plantation located in a semiarid climate

We estimated the rainfall interception (I), canopy storage capacity (S), the ratio of mean evaporation rate from the wet canopy ( ) over the mean rainfall intensity ( ) (mm h-1) ( ), and free throughfall coefficient (p) in a Fraxinus rotundifolia 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 197.2 mm), with 31 events occurring during the growing season (total GR 88.0 mm) and 24 events measured during the non-growing season (total GR 109.2 mm). The mean ratio of I to GR (I:GR)% equalled to be 39.2% during the growing season vs. 23.9% during the non-growing season. For the growing season, S was estimated to be 0.27 mm, 0.21 mm, and 0.23 mm using the minimum, mean, and Gash and Morton methods, respectively. For the non-growing season, these values were estimated to be 0.17 mm, 0.13 mm, and 0.15 mm, respectively. During the growing and non-growing seasons, were estimated to be 0.13 and 0.11, respectively. p was estimated to be 0.39 during the growing season and 0.52 during the non-growing season. The loss of the leaves resulted in decline in I, S, and , and an increase in p. For semiarid regions, these values are useful for solving some water management problems.

canopy storage capacity, Fraxinus rotundifolia, free thorughfall coefficient, Seasonal variability.