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The Next Page / Amazon on the Mon: Pittsburgh's Urban Forest Master Plan
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When Jarlath O'Neil-Dunne looks at an aerial map of Pittsburgh, he doesn't see streets, intersections or addresses. While most of us see our city in terms of the whittled curves of its rivers, and the asphalt streets and neighborhood boundaries carved from their outlines, Mr. O'Neil-Dunne's Pittsburgh is a green-and-gray world of leaves, stems and branches. And that Pittsburgh may surprise even the most boosterish among us.
"If you asked anyone, which has a higher percentage of tree-canopy coverage, Burlington, Vt., or Pittsburgh, Pa., I don't think there'd be much question," says Mr. O'Neil-Dunne, director of the University of Vermont Spatial Analysis Lab.
But the fact is, they're basically the same.
The magic number is 42 percent. That's how much of the city of Pittsburgh is covered by tree canopy. That number is far higher than for cities usually compared with Pittsburgh, such as Baltimore and Cleveland, and it puts Pittsburgh ahead even of leaf-worshipping Portland, Ore.
That canopy percentage isn't easily arrived at, and it is just one noteworthy takeaway from the new Urban Forest Master Plan commissioned by the advocacy organization Tree Pittsburgh, in collaboration with city departments, nonprofits, communities and residents. The master plan -- details at treepittsburgh.org/urban-forest-master-plan -- shows that Pittsburgh's urban forest is not only big and beneficial, but that it also has a posse to back it up.
Still, the master plan makes clear that our fair city has a lot of room for growth -- not only in the actual-living-trees department, but also in terms of extending green cover to all corners of the city and providing cohesive resource management.
Perhaps for the first time, it allows us to see our urban forest as not only nice, but vital -- to the city's competitiveness as a place to live and thrive. And certainly for the first time, it allows us to see how a spectrum of government and non-governmental groups, as well as businesses, institutions and ordinary property owners can together create a strategy to protect and enhance our urban environment.
Trees are nice. Everybody knows that. Unless one falls on your car in a storm, you probably like trees. They're shady and comforting, and they look nice, especially in the spring and autumn. Right?
Let me tell you a few more reasons you should like Pittsburgh's trees.
The more than 2.5 million trees in Pittsburgh saved city residents more than $3 million in energy bills last year, primarily because their shade cuts down on air conditioning. They provided nearly $4 million in air-pollution reduction by trapping particles and absorbing gases. The city's street trees alone -- those not on privately owned land -- intercepted 41.8 million gallons of storm water. As long as we take care of them -- which has its own benefits in education and community-building -- they'll do so again this year, and next year, and the year after that.
But the blessings of our urban forest are not equally distributed. Leafy Regent Square, for example, enjoys 61 percent canopy coverage while the figure for South Side Flats is a more industrial-era 12 percent. That means the Flats get a lot less of those storm-water, energy and air-quality benefits -- not to mention the less quantifiable but well-known arboreal side effects of reduced crime, increased property values and heightened aesthetics.
Pittsburgh advocates have hailed the usefulness and beauty of a leafy city for more than a century. But we can assign numbers to the benefits of our urban forest today only because of new technologies and analytical tools. Pittsburgh's Urban Forest Master Plan put these techniques to work to see how we stack up.
In 2009, Danielle Crumrine and Matthew Erb -- executive director and director of urban forestry for Tree Pittsburgh -- looked at Pittsburgh's green streets and hillsides and recognized a problem. They knew the city had a good tree population -- maybe even better than good. They knew all the ways trees contribute to urban life. But while many Pittsburghers understood the value of trees and fought for them, these advocates were scattered across government, nonprofit and residential groups and hadn't quantified the benefits of trees in a way that could help them persuade a wider public.
So, in 2010, Tree Pittsburgh convened a symposium to bring together long-time advocacy projects, such as the Pittsburgh Shade Tree Commission; newer nonprofit community groups; the city's forestry officials; and large private landowners, such as the universities, whose properties comprise a big chunk of our urban forest. From this group came the idea of the Urban Forest Master Plan -- a comprehensive description and analysis of Pittsburgh's trees and tree-management resources and a strategy for improving our urban forest.
The first question -- what have we got? -- might seem like a simple one. After all, we've got reams of paperwork, maps and numbers about everything in our urban centers, right?
But urban forestry is a relatively young field, points out Joe Gregory, coordinator of urban forestry services for the tree-services company Davey Resource Group and overseer of the master plan. Mr. Gregory has helped with Pittsburgh tree projects since 2005. That's when the Pittsburgh Shade Tree Commission, a nonprofit organization that works with the mayor's office to catalyze tree planting and management on city property, hired Davey to conduct a tree inventory of Pittsburgh.
"The first step was, if we want to take advantage of this resource, we've got to know what we have and how that stacks up with what we want," says Mr. Gregory. "We started that in 2005, and the results didn't stack up -- which sparked a lot of action."
The initial inventory detailed the trees along city streets -- the number, the species and their conditions. But that was only part of the story. The Shade Tree Commission report didn't tell us about the rest of Pittsburgh's trees or describe their impact on our community.
In the seven years since, according to Mr. Gregory, everything's changed. New technologies mean that it's now possible to examine the city's entire tree cover in detail.
One new tool is i-Tree, the U.S. Forest Service's software suite, which can boil down data about urban forests into all kinds of quantifiable statements about how trees affect cities. But i-Tree is a hungry program, and before it can tell you that Pittsburgh trees sequester an annual total of 14,200 tons of carbon dioxide, you've got to feed it a lot of data.
Tree Pittsburgh's Mr. Erb helped oversee all that data collection. For instance, trees on more than 200 random plots of land were sampled. "That's all sent through the i-Tree Eco program, which takes that data to come up with the actual benefits those trees provide in pollution reduction, carbon dioxide, energy savings and more," explains Mr. Erb.
Another new technology that's made a difference is LIDAR imaging. The acronym stands for Light Detection and Ranging.
Traditionally, the urban tree canopy has been gauged by taking an image like a Google map aerial view and simply counting the green parts. (OK, that's an oversimplification. But let's just say it wasn't very accurate.)
"A [normal] imaging sensor only gets reflected energy," says Mr. O'Neil-Dunne, who did the canopy work for the Pittsburgh master plan. "You don't know what's in the shadows. And because most urban trees are individuals or in small patches, that moderate-resolution tree-canopy analysis was often underestimated by 100 percent. LIDAR doesn't care about shadows -- our resolution can detect trees down to 6 feet tall."
The old method was designed for traditional forest canopies, such as those in Yellowstone or the Amazon, where a single tree falling down makes little difference. But if a couple of trees on a city block come down, that could have a major impact on a neighborhood. With the detailed map of the urban forest created for Pittsburgh's new master plan, we can see where there is space to plant more trees and where communities can most benefit.
If Pittsburgh's urban forest does indeed have a posse, Lisa Ceoffe is one of its leaders. As urban forester for the city, Ms. Ceoffe has a unique role to play -- she looks proactively at the state of the city's trees. She doesn't just react to fallen limbs or dying individual trees; she considers the entire forest resource, the diversity of species and the placement and benefits of city trees.
The Urban Forest Master Plan helps Ms. Ceoffe immensely.
"City Planning is undertaking this comprehensive plan for the city, and with the UFMP, I can make sure the tree canopy -- all this information -- is interwoven into that plan," she says.
A lot of that planning comes down to a saying in the urban-forest business: "The right tree in the right place."
For Ms. Ceoffe, this involves risk management. For example, if a tree is going to be planted on a busy street or near a parking lot, it's got to be a salt-tolerant species, or else one icy Pittsburgh winter is going to do it in.
In his work with Tree Pittsburgh, Mr. Erb takes on a similar challenge. The master plan recommends a highly localized strategy, going into communities and engaging with residents to determine what they want their arboreal resources to do, and then having the expertise and the cross-agency buy-in to make it happen.
"If a community's problem is storm water drainage, we'd have to look at how heavy the salt is around where the tree will be," says Mr. Erb. "Birch can handle a lot of water, but not salt. If there's salt, we may try Black Gum -- it's all about having the right tree in the right place."
As a city employee, Ms. Ceoffe focuses on street trees, those on city-owned property. Mr. Erb, on the other hand, looks at ways to improve tree cover on private properties as well. This reflects perhaps the most progressive aspect of the new master plan -- its comprehensive nature and recommendations to divvy up responsibilities among a wide range of cooperating agencies, organizations, institutions, property owners and residents.
As the master plans shows, most of Pittsburgh's urban forest lies on residential property, or that owned by businesses and institutions such as the universities and other major nonprofits. Existing entities like Treevitalize, the street-tree planting program Ms. Ceoffe helps operate; Tree Pittsburgh, focused on community engagement; and the Western Pennsylvania Conservancy partnered to create the master plan and now plan to help implement its recommendations.
This across-the-board strategy for planning, building and maintaining our urban forest is something that all Pittsburghers can get behind. The idea is to make our highly livable city even more livable -- and for everyone, not just those who live in particular neighborhoods.
The Urban Forest Master Plan shows us how trees can be a big part of a better future for Pittsburgh. And how we all can join hands to make that future a reality.
First Published July 1, 2012 12:00 am
