Surface Erosion Control by Contour–Felled Log Erosion Barriers in Post Fire Areas in Eastern Coastal Regions of the Republic of Korea

Recently, large forest fires have occurred along the Baekdu mountain range in the eastern coastal regions of the Republic of Korea. The turbidity of water in streams increased substantially after the forest fires, leading to substantial deterioration in the water quality. Residents living near the burned areas have requested remediation measures to reduce the turbidity in streams during rainfall events. Our research was conducted at the locations affected by the Donghaean fire in 2000 to investigate: 1) the influence of forest fires on the physical properties of the soil and 2) the effectiveness of contour-felled log erosion barriers (CFLEBs) in reducing surface soil erosion. The CFLEBs is a remediation technique in which felled burnt trees are laid along the ground contour to promote water infiltration into the soil and to reduce the movement of sediment by decreasing the amount of surface runoff. The results showed that the hulk density of the surface soils in the burned areas was greater than that in the unburned areas, and that the mesopore ratio of the surface soils in the burned areas was less than that in the unburned areas. These results implied that forest fires damaged the physical structure of the surface soil and made the surface soil more vulnerable to post-fire runoff and hillslope erosion. The slope lysimeter experiments conducted over two years from May 2010 to June 2012 showed that the annual average sediment yields were 17.8 g m super(-2) yr super(-1) in areas treated with CFLEBs and 133.6 g m super(-2) yr super(-1) in areas not treated with CFLEBs. These results demonstrate that CFLEBs are an effective measure for controlling surface soil erosion and thus reducing turbidity in streams. Since burnt trees are often cut down in the Republic of Korea after forest fires to prevent the spread of damage caused by insects epidemics, the construction of CFLEBs from already felled trees would be an economically and ecologically useful method to reduce surface soil erosion and turbidity in streams over large scales.