Green as Money

Urban trees are good investments—if people take care of them.

By Mary Hoff

Imagine being able to conserve energy in your household, improve air and water quality in your neighborhood, and fight global warming. Imagine boosting the value of your home while making the world more beautiful. Imagine doing all of this and saving money too.

Now stop imagining, and do it: Plant a tree. And help care for the trees in your community.

According to a new analysis by the U.S. Forest Service, the benefits of planting trees in Midwestern communities, measured in dollars and cents, far outweigh costs. In fact, depending on species and location, a single city tree in southern or central Minnesota can be expected to generate a net benefit— after the expense of planting, maintenance, and removal are subtracted—of $160 to $3,040 during a 40-year period. The benefit calculations include energy savings, increased property value, reduced storm-water runoff, improved air quality, and carbon dioxide reduction. In the USFS analysis, average annual net benefits ranged from $3 to $15 for a small tree such as a crab apple, depending on where the tree was planted. For a larger tree, such as a hackberry, the benefits ranged from $58 to $76, depending on location.

"What it tells us is that there is a definite return on our investment," says Jill Johnson, coordinator of the USFS Midwest Center for Urban and Community Forestry.

Buns at a Buffet

Trees have always been a part of Minnesotans' urban landscape. But Minnesotans have not always understood or appreciated the many benefits they offer. To some, they were like dinner buns at a buffet: You expected them to be there, but you didn't really pay them a whole lot of attention.

Then came Dutch elm disease. In the 1970s the exotic, insect-borne fungus swept through the state, destroying hundreds of thousands of trees in cities and towns. Shocked out of complacency by the loss, city dwellers and their public officials formed public-private partnerships such as the Minnesota Shade Tree Advisory Committee and St. Paul-based Tree Trust and began working to restore the devastated landscape.

As city workers cut down dead elms, federal and state governments chipped in millions of dollars to help fill the empty spaces with green ash and other more durable trees. Communities formed tree advisory boards, held Arbor Day festivals, planted saplings. Many developed formal urban forestry programs to perform routine tree maintenance and boost the benefits trees provide.

Some cities earned the title "Tree City USA" from the National Arbor Day Foundation by proving their city had met four requirements: established a tree board or department; passed an ordinance guiding tree care; established an annual budget of at least $2 per resident for urban forestry; and planned an annual Arbor Day celebration. Urban foresters were hired to advise private landowners and to bring professional expertise to activities such as deciding which trees to plant where, preventing and managing disease, and guiding pruning and removal of trees on public land.

"Twenty-six years ago, when I walked in the door, Dutch elm disease was the mainstay," says Hutchinson city forester Mark Schnobrich. "That's why I was hired. . . . Before that it was the street guys taking care of the trees to the best of their ability."

In recent years, unfortunately, there has been a trend back to taking urban trees for granted, says Ken Holman, community forestry coordinator with the Department of Natural Resources. With government downsizing, state funding for urban forestry has plummeted to about one-tenth of what it was in 1978. More than three dozen Minnesota towns have lost their Tree City USA designation. In the 1990s, the nonprofit conservation organization American Forests estimated that only one tree was being planted for every four lost to urban sprawl. Some communities have even outlawed curbside trees in new developments because of the bother and expense of dealing with fallen leaves, storm-damaged limbs, and other maintenance.

"With municipal budgets as tight as they've become in recent years, the care and maintenance of the urban forest, especially outside of the Twin Cities, has suffered," says Katie Himanga, a consulting urban and community forester and also mayor of Lake City.

According to Holman, the recent resurgence of Dutch elm disease among city trees can be attributed to the reduction of urban forestry work. He says neglecting urban trees is about as sensible as neglecting to fill potholes on city streets.

"Trees are part of a community's green infrastructure," Holman says. "They provide or improve the same services as power plants, curbs and gutters, water treatment plants, and more. Trees are a good investment."

Returns on Investment

Some communities are starting to pay more attention to their trees. At a public meeting in New Ulm in 2004, Schnobrich extolled the benefits of trees. His talk helped convince city officials to establish a tree advisory board to inventory trees, review tree-related ordinances, and educate citizens on tree care.

"It's a step in the right direction," says New Ulm tree board volunteer and certified tree care advisor Dianne Rodenberg, who helped organize the event. "Now we've got to go out and do what we say we can do."

Rochester, Moorhead, Thief River Falls, Hibbing, and other cities around the state have also ramped up urban forestry efforts by taking tree inventories and developing long-term management plans. As part of its strategy for improving water quality in Lake Superior, Two Harbors is tapping into trees' ability to retain rainwater and reduce polluted runoff.

Burnsville, Eagan, and Maplewood have made trees and other plants part of their storm-water management programs by planting them where they can soak up rain before it runs into storm sewers. Hutchinson has gotten help for its urban forestry efforts from Hutchinson Utilities, which—like all public utilities in Minnesota—is required by state statute to invest part of its revenues in energy conservation measures such as tree planting.

Johnson, the USFS urban forestry coordinator, hopes the USFS cost-benefit study will offer even more motivation by providing both individuals and communities with a bottom-line justification for investing in trees. Homeowners may be happy to hear, for instance, that a large tree, such as a hackberry, strategically placed on the west side of a house can annually save up to $34 in heating costs and $20 in cooling costs while providing air-quality improvements worth up to $8 and storm-water management benefits valued at $10.

On a broader scale, the USFS study is serving as a framework for cost-benefit analyses of forestry efforts in Minneapolis and Le Center. Le Center has calculated its 900 or so public trees to save some $28,000 in energy expenditures and provide some $8,000 worth of storm-water management services each year. USFS researchers found that nearly 200,000 public trees in Minneapolis provide a total gross annual benefit of $24.9 million in energy savings, carbon dioxide emission reductions, air pollution reduction, storm-water management, aesthetics, and enhanced property values. After the costs associated with trees are subtracted, the net benefit averages out citywide to $15.7 million, or $79 per tree per year.

Minneapolis forestry program manager Jim Hermann thinks the study will indeed make a difference for the program in Minneapolis. "It really helps to justify the fact that trees are more than just a nicety—they have taken their place as a necessity, an important part of the urban infrastructure," he says. "Engineers can always tell you how many miles of road and the cost. Well, up until urban forestry started to gather these figures, it was hard to do. Now we have a little better understanding of that value and how it fits into the picture."

Mary Hoff, Stillwater, is a freelance science writer and frequent contributor.