Ryhming Prize Lecture 2012

Wind Tunnel Studies of Shear-Stress Partitioning in Live Plant Canopies

Le lauréat du Prix Ryhming : Dr Benjamin Walter
Friday 26th of April 2013 – 11 :15 – Room ME B10

The main objective of this study was to improve the understanding and the prediction of the sheltering capability of live  plant canopies against sediment erosion. Such investigations are particularly important in times of global warming, where increasing desertification and land degradation, mainly driven by sediment erosion, became major problems in more and more countries worldwide. Previous wind tunnel investigations on shear stress partitioning (a method to quantify the sheltering effect) exclusively used rigid plant imitations like cylinders or blocks for the experiments, which poorly reflect the aerodynamical behaviour of live plants. The influences of the live plants flexibility and porosity on the sheltering effect were investigated by means of surface shear stress measurements. The surface shear stress on the ground beneath the plant canopies determines the onset and the degree of sand, soil or snow erosion, and was measured with relatively high spatial and temporal resolution. The data was further used to improve a theoretical model which allows the prediction of the sheltering capability of vegetation canopies. The results are also relevant for practical applications, e.g. to identify suitable and sustainable counteractive measures against wind erosion for example.