The trees that populate roadsides and homes endure a surprising onslaught of natural and moral evil. Ice storms topple them, beetles infect them with disease, and troubled youth vandalize them. Heck, even some homeowners go Paul Bunyan on them without getting the proper permissions. The perpetual assault on trees requires taking a detailed inventory of urban forests to ensure they thrive.
Between 2006 and 2013, the Washington, D.C., Department of Transportation’s Urban Forestry Administration (UFA) used a typical PDA-based field collection method. A team of 18 arborists at the administration inventoried D.C.’s street trees using clunky handhelds. Back at the office, information from their units had to be uploaded and manually merged in the street tree database, inviting error creep that defied the very purpose of the collection. In 2014, the administration decided to use ArcGIS Online and the Collector for ArcGIS mobile app to monitor the condition of D.C.’s urban forest in real time and automatically merge individual worker’s collected data. Esri also enabled UFA to share information internally and externally and discover the true extent of illegal tree removal in the city.
Like many public works and transportation departments, UFA uses Cityworks. Cityworks accesses maps and layers from the ArcGIS Online universe and allows UFA staff to select the data capture method most suitable to their specific jobs. Consuming the same geospatial services in all the administration’s mapping applications, arborists can immediately make modifications to the city’s tree assets. As those changes automatically merge in a common map, users can view fresh street tree inventory data on any device and perform tasks accordingly. Working in a real-time environment improved UFA’s response times, particularly during severe storms when fallen branches and toppled trees must be promptly removed.
Street trees are far more vulnerable to human beings and the environment than right-of-way assets, such as street signs and fire hydrants. If not responded to quickly, trees can succumb to pests and disease. Knowing the location of an American elm tree infected with Dutch elm disease is fundamental to containing the hazard.
D.C.’s tree protection laws require obtaining a permit to remove mature trees, but that doesn’t stop some property owners from revving up their chainsaws without filling out the proper paperwork. Not knowing the size of the trees removed, the UFA couldn’t properly assess fines on impatient lumberjacks (penalties are based on the felled tree’s actual size).
Lidar visualization in ArcGIS introduced a new fiscal benefit to the city, ultimately uncovering $100,000 worth of unissued fines for illegal felling. The city ultimately settled for $50,000 and used the funds to plant new trees. From inventorying to investigating to harnessing the outreach power of ArcGIS, the UFA modernized its civic tree monitoring and maintenance workflow, saving time and money.
By Matthew DeMeritt, Esri Writer, Esri