Denver will mark Arbor Day early this year with a celebration today, April 26, at 1001 17th Street Plaza, just steps from the 16th Street Mall — where the city is actively chopping down forty-year-old trees to make room for transplants.
"They are literally transplants," jokes Joshua Schneider, spokesman for the Downtown Denver Business Improvement District.
But Amanda Miller, the BID's manager of sustainability initiatives and resident "tree queen," as Schneider calls her, says that removal of the trees was inevitable, and is now part of the $149 million 16th Street Mall project being overseen by the BID for the city and RTD.
The downtown specimens have greatly exceeded performance expectations for trees in similar environments, she says, adding that most inner-city trees only live a quarter of the time that their mall counterparts have. But the saws are still coming out — and in many cases, already have — as the city works to spruce up the downtown area over the next few months.
"These trees are at the end of their useful life span," Miller says. While some may look healthy to the inexperienced eye, many are "growing at a really slow rate," she notes, and many more have "structural issues."
Nearly all of the mall's remaining trees are honey locusts. This makes them more susceptible to disease, she adds, since they are all the same species.
The mall's initial tree collection included 83 red oaks, but the majority of those have died since the mall opened in 1982. To replace the ones that remain, the BID will bring in saplings from out of state — from Texas, Illinois, and some from as far away as New Jersey.
According to Miller, the growing conditions in the tree's respective hometowns are much more forgiving than the extremes of Colorado's climate, and young trees grow up healthier and faster.
The replacement trees are now acclimating to the Colorado weather in two nurseries along the Front Range, according to Andrew Iltis, vice president of planning and development for the BID. Standing at an average height of thirty feet, with a width of twenty feet at their canopies and seven inches at the base of their trunks, these new shade providers are already the same size as the trees they will replace, he notes.
Work crews are leaving the old trees in the ground as long as possible, taking them out just before beginning construction in the area of the mall in which they're located, according to officials.
The collaborative project between the downtown BID and the city began last April and will conclude sometime next year with a complete makeover of the struggling 16th Street Mall. Part of the renovation includes the wholesale replacement of the street's tree canopy at an extra cost of $1.9 million, according to Nancy Kuhn, spokesperson for the Department of Transportation and Infrastructure.The replacement trees are now acclimating to the Colorado weather in two nurseries along the Front Range, according to Andrew Iltis, vice president of planning and development for the BID. Standing at an average height of thirty feet, with a width of twenty feet at their canopies and seven inches at the base of their trunks, these new shade providers are already the same size as the trees they will replace, he notes.
Work crews are leaving the old trees in the ground as long as possible, taking them out just before beginning construction in the area of the mall in which they're located, according to officials.
"Unfortunately, we can’t keep [the trees] due to the extent of the renovation work that needs to be done, and transplanting the current trees is not a feasible option," Kuhn says, describing the extent of the renovation as "building face to building face across the mall."
"We are looking to repurpose any trees we can," Kuhn adds, noting that some of the wood will be used for seating at the upcoming Populus hotel, which is being built at 14th Street and Colfax.
Of the 199 originally planted on the mall, only 143 remained when the renovation of the 1.2-mile-long mall began, according to the project's finding of no significant impact (FONSI) planning document. Other studies note that only 20 percent of the mall's remaining trees were in good structural condition.
A planning document for the 16th Street tree canopy
The Downtown Denver Partnership
New tree species will include Overcup Oak, Swamp White Oak, Honey Locust, Kentucky Coffee, Accolade Elm and State Street Maple. And they will also be planted in better conditions. "A new system and growing environment for trees will also be installed as part of the renovations," Kuhn says.
According to the FONSI, "Although the Mall’s underground tree infrastructure was modern for its time, it is now outdated and provides only one-third of the soil space typically provided for healthy street trees today." The FONSI also notes that the old trees were planted in individual underground tree boxes, which now have overgrown roots.
The new trees will have access to over 1,000 cubic feet of uncompacted soil, which is crucial, says Miller.
This technology/arboricultural infrastructure will help allow these trees to deal with the many challenges faced in an urban environment. These challenges can include urban heat, drought and snow melting products used in the winter such salt, which Miller says will dry out tree roots. "Our dog-friendly city is also a pretty big risk to our trees," she adds.
"As we were thinking about the design for the mall, we were really thinking about how to make it less of a hall and more of a living room," Ilitis explains, noting that the new trees will be scattered throughout the walking area, whereas the old trees were arranged in a mostly straight line. "The trees really play a key role in making this downtown area distinctive."
The new trees will be planted upon completion of phase one of the 16th Street Mall Project. Currently, five blocks out of the thirteen along the mall are undergoing active construction, and three more are under pre-construction utility work, according to the City's project update page.
