Then the gold miners came, and the bartenders, the merchants and the ranchers, the doctors and the builders. They all had favorite trees that they missed from back East -- maples, elms, oaks, lindens -- trees they desperately needed to plant in the arid land. And now, over a century later, no one's complaining: Denver is renowned for its beautiful trees.
Over the last four decades, though, Denver's trees have been dying faster than new ones are planted. Disease, development, pollution and snowstorms are partly to blame, but so is simple age, especially in older neighborhoods north of downtown. "It's something new, and the explanation is that those are some of the earliest areas to be planted," says Jude O'Connor, city forester.
Denver records show that about 1,800 street-side trees have been planted every year since 1998, outpacing the 1,200 that have been removed each year. Still, O'Connor says, "I think there were a lot of years, years in the mid-1960s to the mid-1980s, when we weren't doing a good job of keeping up."
So this spring, for the first time in nearly a decade, the city is giving money to the Park People, a nonprofit group that runs a program called Denver Digs Trees. The money, nearly $30,000, will be taken from the 1998 Neighborhood Bond initiative funds -- some of the biggest projects included in that initiative, such as construction of a new police station and two recreation centers, have yet to begin -- and go toward trees that will be given away or sold cheaply to people who want to plant them in the grassy strips between their sidewalks and the streets. The city has asked the Park People to focus their efforts on Jefferson Park, Swansea/Elyria, La Alma/Lincoln Park and several other north neighborhoods.
The city's assessment of its trees is backed by American Forests, a nonprofit conservation group that conducts high-tech analyses of what it calls "urban forests." Using field data, aerial and satellite photos and a software program called CityGreen, the group maps and measures tree cover and calculates the environmental and economic benefits of trees. For instance, trees shade houses in the summer, lowering air-conditioning bills, and block the wind in the winter, reducing heating bills. They also remove pollutants from the air and reduce stormwater runoff that clogs sewers.
Using American Forests' software and an independent consultant, Boulder recently spent more than $10,000 studying its trees. The results, which will be officially released this spring, indicate that Boulder's trees save city residents $3.13 million every year: $1.4 million in energy costs, $1 million in carbon storage and $730,000 in air-pollution removal. Additionally, the trees reduce stormwater runoff by 12.2 million cubic feet.
According to Paul Lander, a Boulder water-conservation specialist, a primary reason for the study "is to quantify the environmental benefits of trees. Urban-forest budgets go up and down, and if trees are seen as just an aesthetic resource, budgets sometimes get cut." But if Boulder can prove that its trees save the city money, it might qualify for grants and other kinds of funding in the future.
Boulder's study was a preview of an analysis of trees along the entire Front Range whose results will be released by American Forests in mid-February. As part of the latter survey, the group studied eight Denver neighborhoods last September. "When we got this satellite image, it confirmed what we thought, that the central northern neighborhoods seem to be lighter in canopy," O'Connor says. She'll use the results of the larger study to quantify the benefits of Denver's trees in the same way that Boulder did. "I'm hoping we will be able to do it without spending $10,000," she adds.
Although American Forests spokesman Stevin Westcott says he's "not prepared to talk about the report" until next month, the group's magazine of the same name included some of the preliminary findings in its January issue. Canopy cover, as the group calls it, averages about 20 percent in the older parts of cities such as Denver and Boulder, with some neighborhoods coming close to 40 percent. But in newer developments like Rock Creek, which is just off Highway 36 near Boulder, canopy cover is less than 6 percent.
For maximum ecological and economic benefit, American Forests recommends a 40 percent tree cover for most American cities, and 30 percent in the desert Southwest, a region that includes Denver, according to the group. "The interesting thing about Denver," Westcott says, "is it didn't have many trees to begin with, so saying an area like that should have 40 percent is relative to that."
In fact, Westcott says, development along the Front Range actually increases the number of trees, unlike in regions such as the Pacific Northwest and the Chesapeake Bay, where development decreases trees. But unless today's developers see the benefits of trees as clearly as Denver's forefathers did, Colorado's urban forests could still decline, he adds.
Despite the loss of some of its trees (and the occasional misleading newspaper article, including a November New York Times piece that said Denver lacked "the shielding embrace of trees"), there are still nearly 200,000 trees in public areas of the city alone. O'Connor's goal now is to plant a tree for every one that dies and eventually achieve an average of 30 percent tree coverage across the city. But, she says, "we have quite a bit of work left to do to achieve that."
