Water Erosion Correlation between Tree Architecture Models, Soil and Water Conservation at Gunung Halimun-Salak National Park

Mexico. Nevertheless, the value for the Control plot was lower than those reported by the same authors 0.33. It was observed that an increase in rainfall did not produce an increment in runoff for the patches of Castanopsis argentea and Michelia montana likely the Control Fig 10. Given the leaf area index and woody surface area index that characterize Castanopsis argentea and Michelia montana, the probability of a raindrop passing through the canopy without contacting a vegetative surface is relatively low even under strong wind conditions. The aerial structures of the two species intercept a significant amount of rainfall, which is subsequently translocated as stemflow to the soil,increasing infiltration and diminishing the potential for runoff. Cumulative soil loss values were quantified in 1.98, 0.82 and 0.76 ton ha -1 year -1 for the Control, Castanopsis argentea and Michelia montana, respectively. Increases in the amount of surface runoff lead to an increase in soil erosion. However, these relationships are inconsistent in Castanopsis argentea and Michelia montana plot. This result suggests that vegetation patches of Castanopsis argentea and Michelia montana create soil fertility where soil organic matter contents are greater, bulk densities are lower, and consequently, the stability of aggregates and water intake increases, reducing the amount of runoff and soil erosion.

4.3. Correlation BetweenSoil Conservation Parameters

Linear multiple regressions onto rainfall, throughfall, stemflow, runoff and erosion are computed: Fig 10 Runoff relationship A and rainfall-erosion relationship B for different plots. 0,0 0,5 1,0 1,5 2,0 2,5 3,0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 S oil e rosion ra te g m 2 Rainfall mm Castanopsis Michelia Control A 1 2 3 4 5 10 15 20 25 30 35 40 45 50 55 60 65 70 R unof f mm Rainfall mm Castanopsis Michelia Control B Erosion Castanopsis = 0.02 + 0.004 rainfall + 0.06 throughfall + 14.8 runoff -0.4 stemflow Erosion Michelia = 0.65 +0.03 rainfall + 0.16throughfall + 8.76 runoff + 0.34 stemflow The coefficients of multiple determination R 2 = 0.961 and 0.97 are high which, given r = 0.98, is significant P0.01. This indicates that soil erosion is significantly correlated to rainfall, throughfall, stemflow and runoff. These correlations are summarized in Tables 3 and 4 and the results of the Principal components analysis PCA are showed in the biplot Fig 11. Table 3 Matrix correlation for Castanopsis argentea Variable Rainfall Throughfall Runoff Stemflow Erosion Rainfall 1.000 Throughfall 0.919 1.000 Runoff 0.872 0.966 1.000 Stemflow 0.659 0.761 0.758 1.000 Erosion 0.868 0.956 0.979 0.741 1.000 Table 4 Matrix correlation for Michelia montana Variable Rainfall Throughfall Runoff Stemflow Erosion Rainfall 1.000 Throughfall 0.891 1.000 Runoff 0.852 0.976 1.000 Stemflow 0.747 0.791 0.811 1.000 Erosion 0.881 0.979 0.977 0.803 1.000 0,5 0,4 0,3 0,2 0,1 0,0 -0,1 -0,2 1,0 0,8 0,6 0,4 0,2 0,0 -0,2 -0,4 -0,6 -0,8 -1,0 First Component S e c o n d C om p o ne n t Erosion Stemflow Runoff Throughfall Rainfall 0,5 0,4 0,3 0,2 0,1 0,0 -0,1 -0,2 1,0 0,8 0,6 0,4 0,2 0,0 -0,2 -0,4 -0,6 -0,8 -1,0 First Component S e c o nd C o m po n e n t Erosion Stemflow Runoff Throughfall Rainfall Fig 11 Biplot of soil conservation parameters using data from A Castanopsis argentea and B Michelia montana. A B