Rainfall interception in a natural stand of a Fagus orientalis and a Picea abies plantation within the growing season in Kelardasht region, North of Iran

he aim was to compare rainfall interception (I) in a natural forest of Fagus orientalis L. with a neighboring Picea abies plantation in Kelardasht area, the Caspian forests, North of Iran. To measure gross rainfall (GR), four manual collectors were installed in an open area adjacent to the forest sites and throughfall (TF) was measured using 20 collectors randomly located underneath of stands. I was calculated as the difference between GR and TF. Measurements were made from July to November, 2012. During the measurement, 13 rainfall events were recorded with a cumulative depth of 319.8 mm. Cumulative depth of I for F. orientais and P. abies were 84.4 mm and 155.5 mm, respectively. On the event-based measurements, average (I:GR)% in F. orientais and P. abies stands were found to be 26.5% and 48.6%, respectively. Positive power correlations were observed between I and GR in both stands (r2F. orientalis: 0.9; r2P. abies: 0.8). Results showed logarithmic correlations between I and (I:GR)% in F. orientais and P. abies forests (r2F. orientalis = 0.66, (I:GR)% = -9.15ln(GR) + 58.8.; r2P. abies = 0.51, (I:GR)%= -12.28ln(GR) + 91.49). The greater amount of water reaches the forest floor in F. orientalis suggests that the planting of P. abies relative to F. orientalis will have a significant impact on the hydrological cycle of the watershed. Estimating I, along with the transpiration of species, is necessary to consider while selecting the adapted species for reforestation in the derelict areas of the Caspian forests.