Phoenix, Arizona is best known for its cacti and asphalt, not its tree canopy, but one city employee is trying to change that. Richard Adkins, a forestry supervisor for the city, is on a mission to bring tree coverage to one-quarter of the city by 2030. Right now, the tree coverage is less than half of Adkins target number. Why bring lush tree cover to a city mostly known for its desert plants? With a new emphasis on walkable neighborhoods over sprawling subdivisions, and the looming threat of climate change that will raise the mercury further, Phoenix needs to create refuges from the burning heat. Some (mostly older) districts have a reasonable tree cover of 17 percent shade, while others have a paltry seven or eight percent. Natives species like palo brea and mesquite will be planted in conjunction with varieties like the Chinese pistache, a deciduous tree with a dense crown and deep root system that won't buckle sidewalks. As an aesthetic bonus, the pistache turns blood-red in the fall before dropping its leaves. Palms, a ubiquitous site along medians, will be avoided as they do not provide much shade. One model for Adkins's initiative is three-acre Civic Space Park. Completed in 2009, the downtown park boasts a variety of native and non-native trees, pervious pavers, a solar canopy, and a coffee shop. When the trees mature in five to six years, the park should have 70 percent shade cover. And yet, Adkins told the Los Angeles Times, “there’s a lot of pushback – ‘You plant more trees, well, we’re going to have to use more water. That’s where it gets into species choice and water management. Even today, most people over-water everything. But is water a consideration? Of course? Do I feel we have ways of watering and harvesting rainfall with green infrastructure to help provide for our street trees? Absolutely. Do I think we need to give up trees for water? No.” The trees don't need to be natural to be functional, though. Steel trees and canopies can provide cover from the sun on densely developed downtown corridors. In addition creating an online inventory of Phoenix's 92,000 trees, Adkins has tagged trees across town with labels to explain their environmental value using a metric developed by the U.S. Forest Service to determine a tree's carbon storage capacity, how much electricity it could save surrounding buildings, and how much runoff it reduces. Beyond the cost savings they afford, trees have an extra economic value: People tend to gather in shady spots, so if a commercial corridor has many trees, it's likely to get more business, Adkins reasons.
Posts tagged with "Urban Forests":
A proposal for a dense forest along the Rockaways shoreline in New York City could boost storm resiliency in the area. Local Office Landscape and Urban Design, led by Walter Meyer and Jennifer Bolstad, has proposed the forest along the Robert Moses roadway in Rockaway, Queens. The so-called “Rockaway East Resiliency Preserve” would turn the storm-weary Rockaways into a blooming, natural location. The Rockaway East Resiliency Preserve is among the projects adding to the more general plan to install structures and natural objects to better protect the city's coastal areas against future storms. Prior to the arrival of Hurricane Sandy in 2012, the Shore Front parkway stood between the boardwalk and the rest of the residential areas. The parkway, albeit large and four-lanes wide, was rarely used and is on Meyer’s agenda of places to renovate and re-purpose. Meyer intends to take half of this parkway and create an area filled with dunes and trees as a solution to any future problems involving natural disasters. This dune system will house trees of pitch pine, that, when fully grown, will grow thick roots into the ground which will interlock with each other. Once planted, however, these trees will need to or three years in order to be strong and durable. The nature preserve will be well sunken, and will act as an efficient water basin in case of a flood. Meyer has stated his intentions to lower areas of this nature preserve to different heights so as to create an effective dune system. The preserve will also house wetlands and freshwater habitats for animals as well as to quickly absorb water from a flooding. The proposal is currently under review by the Department of Housing Preservation and Development (HPD), and has garnered the support of some local politicians. City Councilman Donovan Richards has taken to supporting the proposal, and stated he would be speaking with HPD department to get this project passed.
[Editor's Note: Following the publishing of this story, the Speed Art Museum and tree researchers studied the tree, determining that it was, in fact, not three centuries old, nor a Valley Oak. The tree in question is now believed to be a 60-year-old English Oak. Read the update here.] The Speed Art Museum in Louisville, Kentucky, is currently closed to visitors until 2015 while a dramatic stacked-box addition is built to the north of the institution's original 1927 neo-Classical building on the University of Louisville's Olmsted-designed Belknap Campus. The $50 million expansion, designed by Culver City, CA-based wHY Architecture with Reed Hilderbrand Landscape Architects, who were later dropped from the project, will triple the museum's gallery space and add to the already robust arts scene in Louisville. This week, one alert writer at the student newspaper, The Louisville Cardinal, noticed something missing at the construction site: the University's oldest tree. The approximately 309-year-old Valley Oak had been cut down when the site was cleared late last year. Only a stump now remains behind the construction fence. The author, Wesley Kerrick, noted the tree pre-dates not just the University, but the city, state, and country in which it resides, as it sprouted sometime in the late 17th or early 18th century. Kerrick expressed frustration over the fact that the tree couldn't have been saved. Dr. Tommy Parker, Director of the Urban Wildlife Research Lab (UWRL) at the University of Louisville, has been observing the University's urban forest for the past several years. The University's 309-acre Belknap Campus contains over 2500 trees, which Parker and his students have been studying and mapping to build a Tree App that geo-locates every tree on campus with information on each tree's species, age, height, environmental contribution, and even monetary value. The mapping project has documented 1,140 trees on campus so far. "This project is useful for understanding wildlife habitats," Parker said. "It allows for real-time analysis in the field." Dr. Parker and his students first collect measurements of each tree, feeding the information through a computer program that estimates its age, value, and environmental benefit. Next, teams geo-locate each tree, finding the exact coordinates using a GPS device. The mapping process helped Parker and Kerrick recognize the Valley Oak's history and that it had been removed. "She was a beautiful tree. I just happened to come in one day and it was gone," Parker said of the three-century-old tree. He lamented the loss of such a historic tree, but noted, "I didn't have a problem with removing the tree. Just that there was no conversation about it. That was the only problem I had." Parker explained that, like other living things, different tree species have different lifespans, and at the end of their prime they can become susceptible to root rot and disease, sometimes requiring removal. "Many people think all trees are like Sequoias," Parker said, "but most trees have a distinct lifespan." For instance, Oaks and Maples, Parker said, can readily live to be 200 to 250 years old, depending on the region in which they're growing. In a southeastern city like Louisville, trees can grow even older. Parker estimated that if the Valley Oak had not been cut down, it could have lived for decades to come. "It was in good shape," Parker said. "That tree could have lasted easily another 50 years." In human terms, Parker said the tree would be about 50 years old given an average human lifespan of 72 years. To replace the old tree with new young trees of the same species and maintain what Parker called the tree's "environmental services" (it's ability to absorb cardon dioxide), the University would have to plant 35 new two-inch-diameter trees. The old tree's diameter measured 51.5 inches, but Parker said the real benefit of such a large tree is its crown, where the leaves are scrubbing the air. Still, Parker is less concerned with the loss of one iconic tree and is helping to push a tree-planting campaign to keep the University's urban forest healthy. In the past two years, the University added 380 trees to its campus, and Parker said it's on target to plant another 300 this year. "We need to think of tree turnover and plan for the next 50 years," he said. "We can't have ten or 15 year gaps in the tree canopy" from trees dying and no new trees being planted. He hoped the loss of the Valley Oak might inspire others to get involved in taking care or and expanding Louisville's urban forest.