Chattanooga Tree Maintenance

The city of Chattanooga spent more than 7,000 hours in 2002 pruning and maintaining nearly 4,500 trees. The city was on a mission to add technology to Chattanooga’s tree maintenance process as part of an effort to document maintenance costs for the city’s urban forest. They are now using GPS and GIS to map tree locations and track the size and type of every tree along Chattanooga’s city streets and downtown parks.

It took four months to inventory the trees in Chattanooga’s expanded central business district, an area that covers about 200 square blocks. Members of the city forester’s team hiked through downtown carrying backpack GPS units, entering data on each tree’s location, species and size of the planting pit. They also noted whether or not the tree was irrigated. Since the data was collected, the Chattanooga Urban Forestry Division created five categories based on the tree diameter and assigned each tree to its appropriate category. Classifying the trees in this way helped determine the number of pruning hours required to maintain them.

In addition to maintenance projections, the GIS tree inventory map helps the city in other ways. Because the map has the power of a database behind it, Urban Forestry personnel can query by tree height, condition, pests, maintenance needs — whatever information is in the database. For example, overloading on one tree species could be disastrous should a pathogen, insect or disease attack that species, so experts suggest that cities have no more than 5 percent of one species in their overall mix. (Source: J. Brown, Saving the Urban Forest, Government Technology, 9/23/2003.)