Experimental analysis of moisture dynamics of litter layers - the effects of rainfall conditions and leaf shapes

The effects of rainfall conditions and the morphological characteristics of leaves on the moisture dynamics of litter layers were investigated. Maximum water storage capacity and interception storage capacity under various rainfall conditions were evaluated for two contrasting litter :types: a needle-leaf type, represented by Cryptomeria japonica leaves: and a broad-leaf type, represented by Lithocarpus edulis leaves. An artificial rainfall simulator was applied to measure each litter type's interception storage capacity under various rainfall intensities. Our results indicated that (1) the maximum water storage capacity of each litter layer was proportional to the litter mass (kg/m(2)) regardless of layer thickness, (2) the litter interception storage capacity increased with rainfall intensity in the range of realistic rainfall conditions (under 50 mm/h); (3) the broad-leaf litter of L. edulis intercepted more rainwater than the needle-leaf litter of C. japonica; and (4) the rainwater moved laterally in the litter layer of L. edulis whereas it moved directly down in the litter layer of C. japonica. These results show that not only the litter mass but also the rainfall conditions and leaf shapes are important in evaluating the moisture dynamics of litter layers. Copyright (C) 2004 John Wiley Sons, Ltd.