Protecting and enhancing the urban tree canopy is an important factor in addressing climate change, heat stress, surface water management, green infrastructure, and environmental justice.
This project for CAGIS established a detailed data set for tree canopy coverage for the City of Cincinnati and Hamilton County that supported change detection and planning. Using LiDAR data collection in combination with aerial imagery enabled higher resolution and more useful measurement of current conditions.
An important part of the effort was obtaining sufficient funding and bringing in stakeholders. Half the funding came from the Metropolitan Sewer District, which was interested in the benefits a detailed impervious service map would provide, as they are looking to create a taxing system for impervious services on private property. CAGIS was also able to get a grant from the U.S. Forest Service and the Ohio Department of Natural Resources to cover the rest of the cost of the Urban Tree Canopy (UTC) assessment. For more information on US funding sources for urban tree canopy assessments, contact AppGeo.
The AppGeo Team for this project included: AppGeo data scientists and geospatial analysts, data scientists from University of Vermont’s Spatial Analysis Lab (UVM SAL), Arborists from SavATree, and imagery data specialists from Quantum Spatial.
Jarlath O’Neil-Dunne’s team from the University of Vermont’s Spatial Analysis Lab collected the lidar data and conducted the UTC assessment, which was quantified using the percentage of coverage for each geographical unit (municipal neighborhood boundaries or census blocks or tracts). Change detection modeling used previous UTC studies performed in 2010 as a baseline. Using Lidar and in contrast to the 2010 data, one of the unique things that was added this time was tree counts, as well as detailed information on each tree, such as crown, crown radius, and diameter of tree can be measured.
“At a very, very precise scale, we’re mapping the gain, loss, and no change. It’s this precise accounting of the gain, loss, and no change that gives you the greatest insights into what is happening to your city. In the case of Cincinnati and Hamilton County, we’re seeing the benefits of tree planting that have happened over a decade ago.”
– Jarlath O’Neil-Dunne, Director, University of Vermont Spatial Analysis Lab
“We didn’t just take a picture of the top of the canopy, [with LiDAR] we actually got to take a picture of an entire canopy and going underneath into the understory; which really provided us really good, relevant information — not just the treetops but the actual trees themselves”
– Matt Dibona, GIS Analyst City of Cincinnati