Estimating linkages between forest structural variables and rainfall interception parameters in semi-arid deciduous oak forest stands.

An understanding of the relationship between canopy structure and the water balance is needed for predicting how forest structure changes affect rainfall partitioning and, consequently, water resources. The objective of this study was to predict rainfall interception (I) and canopy storage capacity (S) using canopy structure variables and to investigate how seasonal changes influence their relationship. The study was conducted in twelve 50m×50m plots in the Zagros forest in the western Iranian state of Ilam, protected forests of Dalab region. Average cumulative I was 84.2mm, accounting for 10.2% of cumulative gross precipitation (G) over a 1-year period. Using a regression based method, S averaged ~1mm and 0.1mm in the leafed and leafless periods, respectively. There were no relationships between tree density and I:G or S, but I:G and S increased with leaf area index, canopy cover fraction, basal area, tree height, and diameter at breast height in the leafed period. In addition, wood area index and canopy cover fraction were related to I:G or S in the leafless period.