Urban trees dataset for Hamburg-Altona, Germany 2022

Trees have a great impact on the thermal comfort in cities. They provide cooling through evapotranspiration and shade. It is therefore crucial to climate adaptation measure for urban planners. To investigate the impact on the urban climate and on thermal stress in particular, high-resolution urban climate models such as PALM-4U are employed, which resolve the 3-dimensional structure of trees. Such models require detailed information about location, height, grown geometry, and tree species. For the city of Hamburg, these information is provided for street trees. However, many trees are located in parks, private gardens, or backyards, which are not covered by this dataset. Hence, a method is introduced to detect urban trees from available remote sensing data using QGIS tools. The resulting Urban trees dataset for Hamburg-Altona provides the location, height, and grown width. A comparison with the existing street tree dataset shows that there is a negative bias with respect to the tree height but with a high correlation. In contrast, the crown width data has only a small bias but a moderate correlation. The documentation file provides a more detailed description of the methodology used to construct the dataset, as well as the evaluation of the dataset. The dataset is available as a GIS shapefile. In addition to tree height and crown width, detected crown radius and crown area are also provided. The dataset uses the 'EPSG:25832 - ETRS89/UTM Zone 32N' coordinate system. In addition to the full dataset, which includes all detected trees, a file from which the street trees have been removed (ending "_cropped") has been prepared. This file only includes private and park trees, making it easier to use as a separate input dataset for a high-resolution urban climate model. Attributes included in the urban tree dataset files: TREE_HEIGHT – height of the tree in m CROWN_WIDTH – crown diameter in m CROWN_RAD – crown radius in m CROWN_AREA – crown area in m^2 Files per dataset: .shp – The main file containing the geometry (i.e. polygons)..shx – The index file that links geometry to attributes for faster access..dbf – The attribute table storing feature data (like names, values, etc.)..prj – Stores the coordinate reference system (projection information)..cpg – Defines the character encoding for the attribute table..qpj – QGIS-specific projection file with more precise CRS information.