Modelling Post-Tree-Harvesting soil erosion and sediment deposition potential in the turano river basin (Italian central apennine)

The overall aim of the paper is the assessment of human-induced accelerated soil erosion processes due to forest harvesting in the Upper Turano River Basin. The spatio-temporal pattern of soil erosion processes was investigated by means of a spatially distributed modelling approach. We used the Unit Stream Power Erosion and Deposition model. During the soil erosion-modelling phase, the forest cover changes were mapped via remote sensing. According to this operation, the forest sectors exploited for timber production amounted to about 2781ha or 9·9% of the wooded surface from March 2001 to August 2011. In this period, the average annual net soil erosion rate estimated by means of modelling operations totalled 0·83Mgha-1y-1 for all the forest lands. The net soil erosion rate predicted for the disturbed forest lands is significantly higher than the average value for the entire forest (5·34Mgha-1y-1). Estimates indicate a soil loss equal to 8521Mgy-1 (net soil erosion 0·34Mgha-1y-1) in the undisturbed forest area (254km2), whereas the 27·8km2 of disturbed forest area could potentially lose 14846Mgy-1. The paper shows that a disturbed forest sector could produce about 74·2% more net erosion than a nine times larger, undisturbed forest sector.