Dynamics of gully side erosion: a case study using tree roots exposure data

Abstract

Erosion is a frequently studied natural process. Unfortunately, detailed analysis mostly requires longterm field monitoring or detailed digital elevation models (DEM) which are still absent for many areas. For these reasons we used the dendrogeomorphic method, a valuable tool for erosion analysis. The slopes of a ~220 m long gully close to the Kozárovce village (Slovakia) were the object of our study. We analyzed 53 tree root samples coming from 16 broad-leaved trees of different species. 23 erosion event years were explored during the reconstruction period AD 1972–2013. The mean erosion rate ER was 1.00 cm/year. We were able to create four erosion patterns of slope erosion based on subsequent exposure of different parts of root. These erosion patterns serve as a base for a model of gully cross profile development. The highest values of erosion rate were reconstructed in the lowest parts of gully slopes. The gully sides formed by volcanic rocks are affected by lateral retreat here. Upward erosion dominates in the middle parts of slopes in loess, and downward erosion in the highest parts of the slopes.

Keywords

• dendrogeomorphology
• slope erosion
• gully
• loess