Application of regression-based methods for determining canopy ecohydrological characteristics of Picea abies stand in Kelardasht

The aim of the present study was to estimate the canopy water storage capacity (S) and ratio of mean evaporation rate from the wet canopy to the mean rainfall intensity ( E / R ) and the direct throughfall coefficient (p) of a Picea abies plantation in a semi-humid climate using the regression methods in Kelardasht, North of Iran. To measure gross rainfall (Pg), four rain-gauges were installed in an open space adjacent to the stand and throughfall (Tf) measured using the twenty rain-gauges which randomly located beneath the canopy cover. Rainfall interception (I) was calculated as the difference between Pg and Tf. Twenty-one rainfall events were recorded with a cumulative depth of 380.1 mm. The Tfand Tf% were recorded 48.8% and 39.6% of the incident rainfall on the cumulative-based and event-based (each Pg), respectively. Positive linear correlation was observed between I and Pg (r = 0.92) and logarithmic correlation was established between Tf% and Pg (R2 = 0.43). The mean value of p, S, and E / R were estimated to be 0.34, 2.15 mm, and 0.43, respectively. Awareness of p and S values can be applied for appropriate silvicultural treatments in forest stands with respect to climate and rainfall.