Yao, C., Fabritius, H., Fricker, P., & Dembski, F. (2024). Research Note: Multi-Algorithm-Based urban tree information extraction and Its applications in urban planning. Landscape and Urban Planning, 253, 105226. https://doi.org/10.1016/j.landurbplan.2024.105226
For more detailed information please contact: chaowen.yao@aalto.fi
Research work supervised by Dr. Prof. Pia Fricker at Aalto university
2021 – 2022
Multi-Algorithm-Based Large Scale Urban Tree Information Extraction and Its Applications in Urban Planning
Abstract
Urban trees provide several vital social and environmental services. Within the field of urban planning, tree information is currently usually obtained through expensive and time-consuming fieldwork. This research presents a multi-algorithm methodology that extracts urban tree information, including tree location, absolute height, crown perimeter, and species (group) from airborne laser scanning (ALS) datasets and high-resolution aerial images. We first determine the location of trees from the ALS dataset. After a filtration step removing the erroneous tree locations, we simulate each location’s canopy based on aerial imagery. Finally, we utilize the extracted canopy images to perform tree species classification with deep learning. The validation assessment showed overall good credibility (>70%) in urban areas and better performance (90%) in street areas. Compared to other methods that require additional information collection, our methodology uses common data in city databases, enabling cities to collect and update large-scale tree information in a fast manner and supporting decision-makers with important information on understanding the value of urban green under the context of ecosystem services, urban heat islands, and CO2 mitigations.

The overarching goal of this study is to discuss the combination of individual computational tools into one multi-algorithm methodology, enabling the extraction of individual urban tree information through a novel integration of existing databases and tools within 4 distinguished steps. By achieving rapid and systematic access to such valuable urban tree information, this approach holds significant potential for a wide range of applications.
Figure 1. Extract tree information including height, crown diameter and species in Helsinki.


Figure 2. Comparasion between orthophoto and information model.
Figure 3. From tree information to 3D model.