A hot-spot analysis of forest roads based on soil erosion and sediment in Zagros forest lands, Iran

Abstract

Forest roads have been recognized as one of the significant contributors to soil erosion processes in forested areas. The construction and maintenance of forest roads can cause severe environmental impacts, including soil erosion, sedimentation, and degradation of aquatic ecosystems. In summary, this study contributes to our understanding of the impacts of forest road networks on soil erosion and sedimentation in the context of Zagros forest land, Iran. This study aims to assess soil erosion and sedimentation on forest roads in four case studies in Zagros forest lands, Iran. The study collected data using field surveys and SEDMODL equations to determine input factors and sedimentation and erosion rates. The study found that road erosion is strongly correlated with geological factor, road width, and precipitation factors. The height changes of 144 benchmarks were recorded during one study year (2021–2022) in four study roads, and the measurement results of erosion benchmarks indicated an average soil erosion of 3, 2.6, 4.7, and 3.5 mm per year around Bidleh, Kohian, Nazi, and Tabrak roads, respectively. The study measured soil erosion and sedimentation at three distances (5, 15, and 25 meters) from the road and found a significant difference in the height changes of the benchmarks at varying distances from the study roads. Hot-spot analysis was conducted using GIS 10.8, and the results indicated that a significant portion of the studied forest roads had very high erosion production and hot-spots. The results of Hot-spot analysis indicated that 30.8%, 22.6%, 39.8%, and 14.5% of the study forest roads in Nazi, Tabrak, Bidleh, and Kohian roads, respectively, are identified as areas with very high erosion production and hot-spots. These results highlight the need for effective management strategies to minimize the impact of erosion on road infrastructure and the surrounding environment. Overall, this study provides important insights into soil erosion and sedimentation on forest roads, and the findings presented here can be used to inform future road construction and maintenance.