A Framework for Assessing Tree Value and Forest Vulnerability Using UAV Remote Sensing

Forests play a vital role in providing diverse ecosystem services, including recreational opportunities for the local population, climate regulation, and timber production, as well as by supporting biodiversity. In parts of Central Europe, the primary function of these forests is to provide a stable and sustainable income for foresters and forest owners. Regardless of the focus, the forests’ ability to provide these services are increasingly threatened by the effects of climate change through extreme events like droughts or floods and biological calamities caused by pests like the European spruce bark beetle. To ensure continuing forest health forest personal is required to maintain dense monitoring in the field in order to act against these dangers. However, such close monitoring using conventional methods can be very time consuming and difficult from the ground. To combat this, this work attempts to get a detailed overview of the economic value of a forest based on individual trees based on UAV remote sensing. Our previous work has proven the effectiveness of UAV LiDAR remote sensing for the delineation of tree stems and their diameter under ideal UAV flight parameters. Building on this, we present a framework combining UAV LiDAR and multispectral data to estimate individual tree value based on diameter, straightness of stem, tree height, and species. Further, the difficulty of harvesting can also be accounted for using information about terrain, density of understory vegetation, and distance to forest and logging roads. This method can further be used to analyse possible areas of increased economic risk for biological pests or extreme events. Overall, this would substantially reduce the amount of fieldwork necessary by foresters and allow for a much more accurate and less tedious method of ensuring continued economic and ecological prosperity.