Using technology also helps keep information current. "The day after an inventory is taken, it's out of date," said Hyde. "Trees die; they get hit by drunken drivers; storms come through and blow them down. It's ever changing, so the technology makes it easy to update. Already we are updating the system almost daily."
The GIS maps can also be shared with other departments throughout the city that need to know tree locations for other city projects.
To this point, the GIS tree inventory cost the Urban Forestry Division approximately $7,000 in staff time. The GPS unit is owned by the county and therefore was available to the division at no charge.
According to the Society of Municipal Arborists, more and more cities are looking to GIS tree inventory programs.
Kansas City, Mo., has inventoried about 40,000 trees so far using GIS from ESRI and Tree Manager software from ACRT. Kansas City officials said they will use their system primarily to manage maintenance and improve the efficiency of tree care.
"We are also looking at mapping other landscape features down the road," said Charles Knight, city forester for Kansas City's Parks and Recreation Department. "We'll look at mapping flower beds, picnic tables, etc., as part of a wider effort at inventory management as well as urban forestry management."
A tree inventory project is also under way in Norwalk, Conn., through the Norwalk Tree Alliance (NTA), a volunteer nonprofit organization whose mission is to initiate and support programs that promote a healthy urban forest in Norwalk. Working with the city, the NTA enlists and trains volunteers to do the legwork as part of a greater plan to preserve and maintain the city's trees.
In 1993, Missoula, Mont., may have been the first city to conduct a comprehensive GIS tree inventory. The number of inventoried trees in Missoula is now over 11,000, and thousands have yet to be tallied.
Hyde said he is not surprised other cities are interested in tree inventories because it's difficult to manage a resource until you know what you have.
"This gets us in the door in terms of knowing and understanding what's out there," he said. "It can help ensure our urban forest survives and thrives in the future."