van Geffen, Femke; Schulte, Luise; Geng, Rongwei; Heim, Birgit; Pestryakova, Luidmila A; Herzschuh, Ulrike; Kruse, Stefan: Tree height and crown diameter during fieldwork expeditions that took place in 2018 in Central Yakutia and Chukotka, Siberia [dataset]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.932817 (dataset in review),

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In: van Geffen, F et al. (2021): SiDroForest: Individual-labelled trees acquired during the fieldwork expeditions that took place in 2018 in Central Yakutia and Chukotka, Siberia [dataset bundled publication]. PANGAEA, https://doi.org/10.1594/PANGAEA.932821

This Individual-labelled trees dataset is a part of the SiDroForest data collection (https://www.pangaea.de/?q=keyword%3A%22SiDroForest%22) and contains spatial data in the form of points and polygons of 872 trees and shrubs that were recorded in Siberia during a 2-month fieldwork expedition in 2018 by the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research in Germany (Kruse et al., 2019). During the fieldwork, 15 m radius vegetation surveys were performed during which information such as height, species, crown diameter were recorded for individual trees. In addition, the vegetation plots were covered by 50*50-meter Unmanned Aerial Vehicle (UAV) flights and Red Green Blue (RGB) photographs were taken with a consumer grade DJI Phantom 4 quadcopter (Brieger et al. 2019). From these UAV images, orthoimages were constructed with Agisoft PhotoScan Professional (Agisoft, 2018) using using Structure-from- Motion/Multi-view Stereo (SfM-MVS) techniques. (Agisoft manual 2019). Orthophotos are geometrically corrected images that are georeferenced. When the individual is located in the orthoimage we also know the location of said individual in real life. The construction techniques are explained in detail in Brieger et al (2019). In these orthoimages, individual trees and shrubs recorded during the expeditions were mapped (Fig 1 in README). The trees recorded during fieldwork that could be located in the orthoimages were marked in a point shapefile and polygon shapefile that outlines the tree crown of the individual tree, each element contains the individual number of the tree, the species and the type (Tree or Shrub). In addition, to clarify between Tree and Shrub, the type attribute was added because in the Chukotka sites there are Pinus species that are shrubs which can be misleading. The Point shapefiles also include the x and y coordinates of the point. The individual number can be used to link the tree or shrub to the rest of the information collected during the expedition such as tree height, crown diameter and vitality.