Earth Observation for SustainableDevelopment in Urban Areas: Resultsand Achievements from ESA’s EO4SD-Urban project

The background of the contribution is the proposed 3-stage forest inventory (Bronner et al., 2018), which involves a third data level between the well-known wall-to-wall airborne laserscanning (ALS) data and the similarly well-known terrestrial laser scanning (TLS) data. We call this intermediate data layer “low altitude laser scanning” (LALS), as it is acquired from an ultralight airplane at low flying altitude and with a tilted sensor to allow a slightly oblique viewing angle. This constellation resulted in a point density of 400 points/m². Previous work on similarly high resolution data has reported high accuracies (Dersch et al., 2021) in managed forests, while we apply this system in a forest, which is currently in transition to a continuous cover forestry (CCF) management system. CCF is a nature-based solution (NBS) system, which relies on single tree harvesting and near-natural species and age mixtures to pertain a resilient and still productive forest (Burschel und Huss 1997, Schütz 2001, O’Hara and Gersonde 2004, Pretzsch 2006). The research questions tackled in this study are 1) How well do existing approaches perform in areas of CCF? 2) How well can different approaches be combined to achieve better accuracies? 3) How can the different information sources be merged to generate added value?