At the end of June, a storm caused massive damage to forest trees in the Berlin region. Thousands of trees were uprooted or snapped. There were numerous broken crowns and branches. Roads and paths along and within the forest are blocked by fallen trees. The worst affected areas are the Tegelsee, Hermsdorf and Spandau forest districts.

IT4Forest enthusiast Stefan Reder supported foresters in Hermsdorf to detect windthrows with remote sensing using a UAV. He flew approx. 40 ha on 3 flights, generated orthomosaics from the 4000 individual images and automatically recorded the storm damage using the WINMOL analyser. The results showed a total of 650 thrown trees were digitally recorded in 3 larger clusters and individual throws.

A cautious estimate of 530 m³ of damaged timber was calculated. However, this might be underestimated, as often only a few metres of the trunk are visible on the orthomosaics, especially in the case of individual windthrows, and parts of the trunk that are covered by crown material were not recognised in the case of extensive windthrows.

Aerial remote sensing can determine the spatial distribution of tree trunks with a detection rate of up to 92%, but it cannot quantify the volume of individual trunks.

Discover the tool: https://stefanreder.github.io/WINMOL_Analyzer/index.html
Explore the background: https://doi.org/10.1016/j.foreco.2024.122411