Estimation of canopy and trunk ecohydrological parameters of Fagus orientalis and Picea abies stands (Siahkal, Gilan province)

The aims of the study were to estimate the canopy and trunk ecohydrological parameters of a Fagus orientalis natural stand and a Picea abies plantation in Siahkal (Gilan province) during one-year measurements. The results showed that the estimated canopy saturation point, canopy saturation point, canopy storage capacity, free throughfall coefficient, the ratio of mean evaporation rate from canopy to the mean rainfall intensity, trunk storage capacity, stemflow partitioning coefficient, and trunk saturation point were 1.81 mm, 1.63 mm, 0.44 mm, 0.57, 0.16, 0.21 mm, 0.13, and 1.61 mm in a F. orientalis stand, respectively. For the P. abies stand, the corresponding values were 3.19 mm, 1.87 mm. 0.94 mm, 0.34, 0.17, 0.19 mm, 0.07, and 2.74 mm. Based on the amounts of canopy and trunk ecohydrological parameters, it can be stated that rain water entering the forest in a F. orientalis stand is more than that in P. abies stand. Due to the time consuming and costly measurements of throughfall, stemflow, and rainfall interception, especially in Iran where there is no possibility of using automated systems, and also because the measurements have to be performed manually in the field after each rain storm, determination of the canopy and trunk ecohydrological parameters is an effective step for predicting throughfall, stemflow, and rainfall interception for each rain storm.