157 Effects of trees towards climate adaptation in Copenhagen A. S. Konring1 and S. B. Petersen1 1DTU Environment, Technical University of Denmark ABSTRACT Urban trees provide multiple ecosystem services that increase amenity value of the urban environment. This has led the municipality of Copenhagen to initiate a strategy to plant 100.000 trees in the city in the period 2015-2025. In addition, the city of Copenhagen is investing billions of DKK in holistic solutions where climate adaptation measures support current urban improvements of a greener city. A central ecosystem service of trees is the retention of water by canopy interception of rainfall and evapotranspiration of soil water. Quantifying the effects of urban trees on these hydrologic processes can help improve the synergy between the strategies. The semi-distributed hydrological model I-tree Hydro was used to simulate the effects of trees in the city of Copenhagen based on historical hourly weather data from 11 years (2005-2015). High-resolution mapping of tree characteristics using remote sensing was conducted to provide an exact estimate of current state. This included using the national aerial Light Detection And Ranging (LiDAR) dataset and Near Infrared ortophotos to derive tree cover and estimate evergreen tree fraction. Moreover, Leaf Area Index (LAI) of the tree cover was estimated using LiDAR with a Beer-Lambert law based model to provide a spatial distribution of leaf storage. The current tree cover in the municipality of Copenhagen was estimated to be 13.5 % while mean LAI of the tree cover was 3.4. Model results show that the evaporation of intercepted precipitation varied from 1.5 % in winter to 2.7 % in summer of total precipitation. Evapotranspiration was highest in the summer season with 9.7 % of total precipitation while only corresponding to 1 % in the winter season. Thus, urban trees in Copenhagen were representing 7.4 % in the urban water balance. Planting of 100.000 trees was estimated to increase interception and evapotranspiration in 2025 with 0.7 % and 0.3 % respectively. Determining the hydrological effects of urban trees in Copenhagen can contribute to the holistic assessment of nature in future climate adaptation projects. In addition, the highresolution tree cover and LAI mapping enable the quantification of other ecosystem services such as air quality, water quality, temperate regulation and CO2 reduction for a complete valuation of urban trees. 810 BUILDINGS AND INFRASTRUCTURE POSTER IDEA MASTER THESIS
Grøn Dyst 2016
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