The intrinsic value of trees is well established: They improve air quality while providing shade and food for humans and animals alike. But a new study looks to establish a long-term monetary value.
“For every $1 spent on planting, from the time a tree is planted until it’s 50 years old, a tree generally give you $1.85 in benefits,” Gerry Bates said. “And that’s the minimum. The maximum side is $2.40.”
Bates is the south Idaho community forestry assistant for the Department of Lands. The agency is using a $300,000 federal grant to calculate the total urban tree canopy in eastern Idaho. The Snake River Canopy Analysis Project, which starts Monday, will measure shade coverage provided by trees in Idaho Falls, Ammon, Blackfoot, Shelley, Chubbuck and Pocatello.
Idaho Falls city forester Delbert Lloyd said the contribution made by trees shouldn’t be underestimated.
“They cool the air, they slow traffic, they are beautiful, most importantly they help with pollution,” Lloyd said. “(Air quality) is becoming a problem and trees help to mitigate that. They save the city money.”
The project will study 300, one-tenth acre plots of ground, spread out across 125 square miles.
Four project interns will work during the summer, using data gathered from aerial photographs and field expeditions to help them calculate the shade coverage in each of the cities. A geographic information systems-based program — or mapping software — that will take data from the 300 plots and extrapolate it over the entire 125 square-mile region.
The interns are being using office space at the city of Ammon’s Parks Department. Parks Director Ken Knoch said the city wanted to help in any way possible.
“They needed a place that the interns could call home, so to speak,” he said.
Knoch said he is excited to see the long-term effects of the project.
“Over time we want to go back and check these plots and see if there are any housing developments or whatever,” he said. “It’s a real benefit to this side of the state.”
The final data should be about 90 percent accurate, Bates said. Similar studies were done three years ago in the Coeur d’Alene and Boise areas.
Bates estimated the shade coverage provided by trees in the 125 square miles is about 7 percent. An ideal amount is 25 percent, he said.
Shade can provide far-reaching benefits — helping to decrease utility costs and extend the life of asphalt, for example, while at the same time limiting the amount of the volatile organic compounds, such as carbon and petroleum, released from asphalt when exposed to high heat. They also help capture storm water, Bates said.
“There’s a lot of benefits that people don’t think about when planting trees,” Bates said. “That’s what we are trying to promote.”
Greg Weitzel, Idaho Falls parks and recreation director, said the city helped write the grant proposal and fully supports the project.
The city promotes tree planting, Weitzel said, and on its website provides a list of trees approved for planting.
“We want to increase and promote (tree) species diversity so they are less susceptible to disease,” Weitzel said. “I think that native trees grow better and are going to last longer. We want the kind of trees that are going to flourish here.”
Once the final data is collected in September, it will be given to the cities. While the cities are under no obligation to make any changes to urban canopy coverage, the project’s goal is to bring more trees into the area.
Bates said he and his coworkers will be available to help the cities that decide to increase their urban canopy coverage.
“Lots of times in a downtown area, if it’s not properly planted, trees will last about 15 to 20 years,” he said. “Because of the restricted root area, they kind of decline and die or they just quit growing and never reach their potential. We are trying to minimize those types of planting policies.”
Interns Megan Reilly, 40, and David Penny, 21, will work primarily in the Idaho Falls area. Since the bulk of the plots to be measured are located on private property, Reilly and Penny have been getting permission from landowners so they can conduct the necessary research.
“The methods are pretty straightforward,” Reilly said. “But I think the execution will vary plot to plot. Some of them are on a river bank, some are smack-dab in the middle of a freeway lane.”
Others, such as plots in aggricultural fields, are quick and easy to assess, Penny said.
Bates said the plan is to revisit the project in 10 years to see whether the data was used to increase the urban canopy coverage. His hope is the data will coerce the cities to invest more heavily on trees.
“What will be the benefits in five years, 10 years or 50 years?” Bates said. “It lets (the cities) strategically develop planting projects that will maximize the benefits that the canopy gives to the cities. It justifies having a successful tree program.”