Laser scanning and eDNA as innovative methods for assessing site productivity in climate-resilient forests

The assessment of site productivity (also referred to as site quality, site potential, site index, or yield class) is a fundamental pre‐ requisite for sustainable forest management. In climate-resilient forests, characterized by increasingly complex structures — dri‐ ven by mixed species stands and the necessity to respond to or mitigate disturbances such as drought, pests, or storm damage — traditional methods of forest inventory and site assessment are reaching their limits, being feasible only at high cost and with substantial effort. The aim of this project is therefore to develop innovative approaches that allow site productivity to be recorded digitally in an efficient, flexible, and large-scale manner. The project focuses on three methodological pillars: Remote sensing as an efficient digital tool for growth monitoring Laser scanning will be used to accurately determine growth parameters such as whorl spacing and height increments, both through terrestrial and personal laser scanning (TLS/PLS) as well as by comparing temporally repeated airborne laser scanning surveys (ALS). Complementary, digitally recorded dendrometric parameters at the tree and stand level will be integrated in order to derive site productivity independently of stand age through forest growth models and to represent it spatially at high resolution using modern statistical methods. eDNA as a site indicator The project will evaluate the potential of environmental DNA (eDNA) from soil samples as an integrative measure of traditional site characteristics (e.g., nutrient or water availability). The reliability of this approach will be tested and validated through com‐ parison with established site data and maps. Integration of site and yield data The systematic integration of eDNA, classical site parameters, and laser-derived growth data will serve as the basis for large-scale modeling of forest productivity. This will be achieved by combining terrestrial measurements with spatially extensive airborne laser scanning data, supported by modern statistical techniques