TY  - JOUR
A1  - Mohr, Christian Heinrich
A1  - Coppus, Ruben
A1  - Iroume, Andres
A1  - Huber, Anton
A1  - Bronstert, Axel
T1  - Runoff generation and soil erosion processes after clear cutting
JF  - Journal of geophysical research : Earth surface
N2  - Timber harvesting by clear cutting is known to impose environmental impacts, including severe disturbance of the soil hydraulic properties which intensify the frequency and magnitude of surface runoff and soil erosion. However, it remains unanswered if harvest areas act as sources or sinks for runoff and soil erosion and whether such behavior operates in a steady state or evolves through time. For this purpose, 92 small-scale rainfall simulations of different intensities were carried out under pine plantation conditions and on two clear-cut harvest areas of different age. Nonparametrical Random Forest statistical models were set up to quantify the impact of environmental variables on the hydrological and erosion response. Regardless of the applied rainfall intensity, runoff always initiated first and yielded most under plantation cover. Counter to expectations, infiltration rates increased after logging activities. Once a threshold rainfall intensity of 20mm/h was exceeded, the younger harvest area started to act as a source for both runoff and erosion after connectivity was established, whereas it remained a sink under lower applied rainfall intensities. The results suggest that the impact of microtopography on surface runoff connectivity and water-repellent properties of the topsoil act as first-order controls for the hydrological and erosion processes in such environments. Fast rainfall-runoff response, sediment-discharge-hystereses, and enhanced postlogging groundwater recharge at catchment scale support our interpretation. At the end, we show the need to account for nonstationary hydrological and erosional behavior of harvest areas, a fact previously unappreciated in predictive models.
KW  - infiltration
KW  - runoff
KW  - erosion
KW  - connectivity
KW  - rainfall simulation
KW  - catchment
Y1  - 2013
U6  - https://doi.org/10.1002/jgrf.20047
SN  - 2169-9003
VL  - 118
IS  - 2
SP  - 814
EP  - 831
PB  - American Geophysical Union
CY  - Washington
ER  -