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Floor Cover Percentage Determines Splash Erosion in Chamaecyparis obtusa Forests
Author(s) -
Miura Satoru,
Ugawa Shin,
Yoshinaga Shuichiro,
Keizo Hirai Tsuyoshi Yamada
Publication year - 2015
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2015.05.0171
Subject(s) - splash , chamaecyparis , erosion , environmental science , litter , hydrology (agriculture) , sediment , forest floor , forestry , rill , canopy , throughfall , ecology , soil water , geology , soil science , geography , geomorphology , biology , geotechnical engineering , paleontology , meteorology
Plantations of Chamaecyparis obtusa (Siebold & Zucc.) Endl. are susceptible to soil erosion following significant decreases in forest floor cover. We quantified the relationship between forest floor cover and erosion under C. obtusa stands to provide information on soil conservation for sustainable forest management. We measured the forest floor cover percentage (FCP) as the percentage of ground covered by litter or understory 0 to 50 cm above the ground surface. We measured the erosion rate (g m −1 yr −1 ) using 25‐cm‐wide sediment traps on steep slopes in Japanese C. obtusa stands where splash soil erosion was dominant. We confirmed that the amount of transported sediment ≤22.4 mm in diameter significantly decreased with increasing FCP and defined these small size categories of sediments as “transportable size sediments” (TSS). The amount of transported TSS increased by 66% in association with a 10% decrease in FCP in the stands with a FCP of 30 to 90%. However, the increase in transported TSS reached a ceiling close to 0% FCP but matched field observations for values up to 100% FCP. Using this quantitative relationship between FCP and sediment transport, we proposed 80% FCP as a target guideline for soil conservation under C. obtusa canopies. Incorporating our results into the Revised Universal Soil Loss Equation indicates that erosion from C. obtusa stands on steep slopes with a low FCP is as significant as in rill‐dominated arable land and abandoned mine sites. These results suggest that soil erosion in these forests can be controlled through management of the forest floor coverage.