The Comparison of Throughfall between Evergreen Coniferous and Deciduous Broad-leaved Forests during the Snow Cover Period

Abstract

We observed throughfall under evergreen coniferous (Cryptomeria japonica stands: large DBH, small DBH) and deciduous broad-leaved forests (Alnus inokumai stands) five times during snow cover periods (from December 24, 2008 to March 25, 2009) in the Yamagata experimental forest in FFPRI, Japan. The order of canopy openness values was Alnus inokumai>Cryptomeria japonica with small DBH>Crptomeria japonica with large DBH. The order of throughfall was the same as the canopy openness order. Throughfall in Almus inokumai stands was 119% greater than in Cryptomeria japonica with small DBH stands and 143% greater than in Cryptomeria japonica with large DBH stands, with integration over five measurement times. A highly positive linear relationship (R²=0.839, p=0.01) was found between canopy openness and throughfall in the Cryptomeria japonica with large DBH stand. A logarithmic relationship (R²=0.781, p<0.001) was found between canopy openness and throughfall for all data. These results suggested that clarification of the relative mixture of evergreen conifer and deciduous broad-leaved trees was important to the quantitative evaluation of the water balance in the Kamabuchi experimental watersheds.