Mountain forests offer effective, natural and cost-efficient protection against avalanches. Trees reduce the
probability of an avalanche formation and can significantly decelerate small to medium size avalanches. Remote
sensing methods enable an efficient assessment of forest structural parameters on large scale and therefore
determine the protective capacity of a specific forest. The aims of this study are: (i) to evaluate the quality of
forest structural parameters obtained from remote sensing data using two different methods; and (ii) to determine
how forest parameters and forest cover changes influence avalanche runout. We compared the control
assessment of maximum tree height and crown coverage in 107 plots (50 in evergreen and 57 in deciduous
forests). The same parameters were analysed using (i) a photogrammetry-based vegetation height model (VHMP)
and (ii) a LiDAR-based vegetation height model (VHML). The control assessment of surface roughness was
compared to the analysis of a digital terrain model (DTM). We then simulated two avalanche case studies near
Davos (Switzerland) with forest parameters estimated by the remote sensing and control methods. Tree height
and crown coverage assessed with both remote sensing methods (VHMP and VHML) did not differ significantly
from the control measurements. However, surface roughness was underestimated. This had a significant influence
on simulation results. For the first case study, a wet-snow avalanche, the simulated runout distances did not
differ significantly, when using forest parameters from either of the two tested remote sensing methods. The
simulated runout distance increased for an avalanche scenario with less forest cover in the release area and/or
less forest cover after forest destruction by a preceding avalanche event. For the second case study, a dry-snow
avalanche, the forest cover was underestimated by the VHMP, which led to longer simulated runout distances.
Our study indicates that available remote sensing methods are increasingly suitable for the determination of
forest parameters which are relevant for avalanche simulation models. However, more research is needed on the
precise estimation of forest cover in release areas and understanding how forest cover changes affect avalanche
runout. Forest avalanche, Remote sensing, Avalanche simulation
