Professor calls for sustainable choices in city’s changing urban forest
There is an old Iroquois philosophy, often cited by modern politicians, public officials and environmentalists, that today’s decision makers need to consider the impacts of their actions seven generations into the future.
For Chico’s urban-forest manager, Denice Britton, this “Great Law of the Iroquois” is not just a catch phrase or high-minded ideal, but also a daily challenge. As the woman most responsible for the health and safety of trees growing within the city—Chico’s urban forest—since 2006, her day-to-day business is directly affected by the actions taken by town founder John Bidwell and other early settlers more than seven generations ago.
And, as the city considers a new Urban Forest Management Plan, a draft of which is currently up for public consideration on the city’s website, the distant future is very much on the mind of Britton and others interested in Chico’s trees.
“These are policy decisions the city needs to consciously make,” Britton said of the plan, noting a long-running controversy involving how the city cares for large, aging trees and its current and future planting policies. “Do we go for the gusto and plant great big trees that we ultimately can’t afford to maintain, or do we plant moderate-sized trees that get 50 to 60 feet tall and are easier to take care of?”
Britton explained that maintaining Chico’s flora is a delicate balancing act involving environmental, fiscal and public-safety issues, and that the decisions are not hers alone to make.
Chico has a three-person Tree Committee—a subset of the Bidwell Park and Playground Commission—that has been working on the draft urban-forest plan for the last year. The committee has public meetings on the second Wednesday of each month; Britton expects the April meeting to be the committee’s final look at the draft before it’s passed to the BPPC and then City Council for approval.
In addition to the BPPC and city staff, about a dozen community members who care about Chico’s trees regularly attend tree-committee meetings. One of them is Kristina Schierenbeck, a Chico State biology professor, botanist and conservationist who has praise for Britton’s efforts.
“She’s doing a great job of balancing input from a lot of folks,” she said.
But Schierenbeck is also critical of the city’s tree-planting policies. Particularly, she is unhappy the city’s list of more than 50 approved trees includes fewer than 10 native species. She is also concerned that many of the species used to replace Chico’s aging and failed trees won’t grow as tall. Schierenbeck said she hopes the new urban-forestry plan will address these concerns.
“The importance of planting native vegetation can’t be understated,” Schierenbeck said, “and I think it’s very important they be reminded that the General Plan speaks specifically to the importance of planting natives.
“The other thing is to not plant invasive species. I just want to encourage the city to stay the course of continuing to be a little more progressive about its planting practices.”
Schierenbeck said some trees the city plants—particularly Chinese pistache and London planetree—are dangerously invasive. The latter species, she said, can potentially hybridize native trees to extinction. She also stressed the positive aspects of planting native trees, such as assisting in pollination and bolstering the declining local bee population.
She pointed out that Chico’s natural habitat was riparian forest, like what is seen alongside Chico’s creeks—valley oaks, California sycamores and other large trees accompanied by a thick ground vegetation—and she would like to see Chico’s urban forest be an extension of that. This type of vegetation once dominated much of California’s landscape, and now less than 2 percent remains, she said.
As for size of the trees, Schierenbeck said many of the species on the city’s tree list are smaller ornamentals that are often seen decorating parking lots and other developments, or “mall trees,” as she called them.
“All you have to do is look at Main or Broadway streets to see what I mean,” she said. “Most of the big old trees are gone, and if there are any left their days are numbered.”
Schierenbeck said she understands some of the rational that leads to planting smaller, non-native trees. For one, the nursery industry is more focused on ornamentals, limiting the availability of natives. City planners would also need to provide larger planting strips in urban areas to accommodate the large trees’ root systems, and big trees also present public-safety issues, as upper limbs can fall unexpectedly.
“Sure, I don’t want my kid to be crushed by falling limbs,” she said. “Nobody does. But we have to ask what the real risk of that happening is and what we’re willing to sacrifice because of that risk.
“If we’re serious about sustainability, the question is, what are we sustaining? What we need to sustain is biological diversity, and that can’t be done by planting more crepe myrtles and Chinese pistaches.”
Britton noted the same concerns about safety and availability of native plants, but said another challenge to Chico’s urban forest is even more difficult.
“The biggest issues we face are fiscal,” she said. “It’s a matter of funding and staffing just to maintain the existing trees. We have four people on our tree crew to maintain the 28,000 trees that we already have.”
She explained the staff does most of its work maintaining and pruning healthy trees from a lift truck with a 65-foot reach. Many of Chico’s older trees are in the 100- to 120-foot range, and the tree crew has to climb them to maintain them, which is more time-consuming and thus more costly.
Britton has instituted some programs to help offset costs. Since 2009, the city no longer plants new trees unless they are replacing old ones, and has moved to a citizen planting system. They are also exploring the possibility of selling wood from valuable trees they have to remove, such as black walnut. As it stands, tree-removal contactors get to keep the wood and sell it themselves.
Britton noted that, though somewhat smaller, many of the species are still fairly large.
“I think that in 50 years people will still be happy and proud if we have a 60-foot canopy instead of an 80- to 100-foot canopy,” she said.
Schierenbeck isn’t so sure.
“It could end up looking like any other boring valley town,” she said. “I hate to imagine it, but it will look like Fresno.”