Seasonal Variability of Rainfall Interception and Canopy Storage Capacity Measured under Individual Oak (Quercus brantii) Trees in Western Iran

While the hydrological balance of forest ecosystems has often been studied, quantitative studies on the seasonal variability of rainfall Interception (I) and Canopy Storage Capacity (S) by individual trees are less frequently reported. Hence, the effects of the seasonal variation in I and S by individual Persian oak trees (Quercus brantii var. Persica) in the Zagros forests of Iran were studied over a 1-year period. Annually, I accounted for 84.9 mm (20%) of Gross Rainfall (GR) that significantly differed between the in leaf (47.4 mm or 30% of GR) vs. leafless (37.7 mm or 14% of GR) periods. Negative logarithmic correlations existed between I:GR and GR both for in leaf (r2= 0.808) and leafless (r2= 0.709) periods. An indirect method, outlined by Pereira et al. (2009), estimated S to be 1.56 mm in the in Leaf Period (LP) and decreased considerably to 0.56 mm in the Leafless Period (LLP). The results indicate that while I decreased during the LLP, it still exerts considerable influence on the hydrology of forests. Hence, measurement of I in both the LP and LLP is essential when assessing the water balance on the catchment scale.