remote sensing Article UAS Imagery-Based Mapping of Coarse Wood Debris in a Natural Deciduous Forest in Central Germany (Hainich National Park) Christian Thiel 1,* , Marlin M. Mueller 1 , Lea Epple 2, Christian Thau 3, Sören Hese 3, Michael Voltersen 4 and Andreas Henkel 5 1 German Aerospace Center, Institute of Data Science, Maelzerstraße 3, 07743 Jena, Germany;
[email protected] 2 Department for Earth Observation, Friedrich-Schiller-University, Loebdergraben 32, 07743 Jena, Germany;
[email protected] 3 Department for Physical Geography, Friedrich-Schiller-University, Loebdergraben 32, 07743 Jena, Germany;
[email protected] (C.T.);
[email protected] (S.H.) 4 TAMA Group GmbH, Lochhamer Str. 1, 82166 Gräfelfing, Germany;
[email protected] 5 Administration of Hainich National Park, Nature Protection and Research, Bei der Marktkirche 9, 99947 Bad Langensalza, Germany;
[email protected] * Correspondence:
[email protected] Received: 11 September 2020; Accepted: 6 October 2020; Published: 10 October 2020 Abstract: Dead wood such as coarse dead wood debris (CWD) is an important component in natural forests since it increases the diversity of plants, fungi, and animals. It serves as habitat, provides nutrients and is conducive to forest regeneration, ecosystem stabilization and soil protection. In commercially operated forests, dead wood is often unwanted as it can act as an originator of calamities. Accordingly, efficient CWD monitoring approaches are needed. However, due to the small size of CWD objects satellite data-based approaches cannot be used to gather the needed information and conventional ground-based methods are expensive. Unmanned aerial systems (UAS) are becoming increasingly important in the forestry sector since structural and spectral features of forest stands can be extracted from the high geometric resolution data they produce.