Tree resistance to wind: the effects of soil conditions on tree stability

Wind damage represents more than 50% by volume of forest damage in Europe. Recent evidence suggests that wind damage could double or even quadruple by the end of the century with dramatic consequences for the forest economy and the ecological functioning and survival of European forests. Most trees during storms are uprooted. While a large amount of work has been done over the last decade on understanding the aerial tree response to turbulent wind flow, much less is known about the root-soil interface, and the impact of soil moisture on tree uprooting. This paper investigates at tree scale the effects of soil conditions, such as water saturation during storms, on tree stability. Our analysis is based on (i) the critical bending moment that induces tree uprooting measured from static pulling experiments (ii) the soil mechanical properties as function of climatic conditions measured and modeled from laboratory measurements (iii) new techniques developed for studying the mechanics of tree structure incorporating 3D roots architecture and numerical biomechanics modeling