Influence of Canopy Interception and Rainfall Kinetic Energy on Soil Erosion under Forests

Abstract

Afforestation is a widely accepted measure to control soil erosion around the world. A large area of forest has been built to prevent slope soil erosion in the red soil region of southern China since the 1980s. The vegetation coverage has significantly increased; however, there is still moderate or severe soil erosion under the forest. In order to improve the situation, it is necessary to study the effects of canopy on soil erosion under the forest. Standard runoff plots were established on two typical sites, which represented pure Pinus massoniana Lamb. forest and bare land, respectively. Precipitation redistribution and throughfall indices including raindrop size, raindrop velocity, and the kinetic energy (KE) of raindrops were quantified. The results showed that 29.3% of the precipitation was directly prevented from reaching the forest land surface. The canopy interception effect was better under low rainfall intensity than high rainfall intensity. Compared with open rainfall, throughfall raindrops were 16.3% fewer in number, larger in size, and the range of throughfall drop size distribution (DSD) was enlarged. The volume ratio of large drops was larger with higher rainfall intensity. When the rainfall intensity was less than 14 mm h−1, throughfall kinetic energy (TKE) was higher than open rainfall kinetic energy (OKE) owing to the higher volume ratio of large raindrops. When the rainfall intensity was more than 14 mm h−1, TKE was smaller owing to the large raindrops failing to reach their final velocities: their mean velocity was 80% of their final velocity. The sediment yield was the largest under high rainfall intensity and the effect of sediment reduction was the largest under moderate rainfall intensity. Therefore, the largest KE did not lead to the maximum sediment yield; canopy interception was also an important factor affecting sediment yield.

An Indicator-Based Approach to Assess the Readiness of Urban Forests for Future Challenges: Case Study of a Mediterranean Compact City

“…Finally, the results obtained for indicator 16, which establishes the percentage of continuous surface covered by tree canopy, were analyzed. This indicator can have different interpretations, since it is a value that is used for the assessment of ecosystem services, such as the mitigation of air pollution [105] or the reduction of the kinetic impact of raindrops [106]. In our case, since the purpose was to carry out a check on the current state of UFs and its immediate effect on the comfort of users, we associated the canopy percentage to the provision of shade, since one of the characteristics that can most prevent visits to UFs is the lack of thermal comfort.…”

Pioneer biocrust communities prevent soil erosion in temperate forests after disturbances

“…Comparatively, Safari et al (2016) reported an increase in erosion rates of a factor of 14 for bare wheel tracks of skid trails up to 301.65 g m -2 h -1 relative to the undisturbed forest floor. These findings suggest, that it is not primarily the forest canopy which protects the soil against erosion, but an intact forest floor (Elliot et al, 1999;Li et al, 2019;Seitz et al, 2016;Shinohara et al, 2019). Several studies have also confirmed that soil erosion on skid trails was highest in the first year after logging and decreased significantly thereafter, primarily due to revegetation (Baharuddin et al, 1995;Jourgholami et al, 2017).…”

Influence of land use and occupation on water quality and on the diatom community of reservoirs in northeast Brazil

“…In well-preserved watershed, with functional riparian forests, changes in factors such as the watercolour and concentrations of suspended solids and phosphorus, occur in a less magnitude (Li et al, 2019). The preservation degree of the riparian zone indicates the relevance of vegetation cover as a mechanical impediment for surface runoff, reducing soil loss and sediment transport to the reservoirs (Flores et al, 2019).…”