Development and validation of the modelling of storm damage in forests

Background and Objective

Damage caused by windthrow or log breakage has far-reaching economic, ecological and social consequences. Besides the direct damage (primary damage) to the stand caused by storms (windthrow and wind breakage), consequential damage (secondary damage) is mostly caused by subsequent calamities such as bark beetles or other factors such as fire, sun, snow/ice or additional wind damage. Losses (tertiary damage) also occur due to loss of production caused by shortened rotation periods and other long-term restrictions in forest use (Gardiner et. al 2014). In addition, there are higher costs for the much more difficult processing and increased costs of recovery. In addition to the reduced revenue due to the storminduced quality losses, the sales prices for storm damaged timber usually fall sharply again, since the markets are oversaturated by the usually massive volume of storm damaged timber.
Crisis management after storm calamities poses great challenges for forest owners. This is because there is a lack of instruments for minimising the risk in the forest in the event of a storm.
Photographs taken from the forest stand do not show the extent of the damage sufficiently. Pictures from UAVs allow a better overview and a first assessment of the damage area, the direction of throwing or the lying direction of the individual trees. These images are invaluable, especially for the creation of skid trails.

Approach

The planned project therefore aims to develop methods and models to quickly identify and map acute and potential storm casts in the terrain in order to avoid subsequent calamities as far as possible. This can help foresters to detect storm areas even in remote areas, including the rapid detection of infrastructure damage and the targeted prioritisation of upcoming work. Furthermore, the fast and exact determination of the location of the storm area and the better planning possibilities can optimize the felling of transport routes and thus less timber can be felled additionally. In addition, the quick removal of timber helps to minimize calamities caused by bark beetles, for example, and thus to protect the remaining stock.