Sheet and gully soil erosion based on exposed tree roots and USLE in central Mexico

In recent decades, human activities have intensified soil erosion, making it a global environmental problem. Yet, its quantification remains challenging. Here, we analyze and compare sheet and gully erosion rates using dendrogeomorphological methods (exposed roots) and the Universal Soil Loss Equation (USLE) in a severely eroded area of central Mexico. Sheet erosion rates were calculated from disturbances in the exposed root tree rings of Juniperus deppeana, with rates ranging from 5.1 to 14.4 mm/year. In addition, the origin and evolution of a gully were reconstructed, with the first erosional pulse dated to 2006, followed by other major pulses in 2015, 2016 and 2018. Sheet erosion rates obtained with the USLE were between 4.5 and 11.7 mm/year for “sparse vegetation cover” and between 2.0 and 5.1 mm/year for “reforestation of eroded areas”. These values were similar to those calculated with the dendrogeomorphological method; therefore, they can be used in a complementary way. The results obtained with the dendrogeomorphological method are precise and cover a longer time span (tens of years), but they require validation with other methods. The USLE is a model of easy application, but it requires calculating and adapting the factors to the study site. This research represents a significant contribution to the understanding of erosional dynamics in tropical highlands, providing valuable knowledge for the development of effective environmental management and conservation strategies.