Growing our cities doesn't have to mean building miles upon miles of new infrastructure and removing the natural landscape. The time has come to consider the urban forest as a working, physical asset. The question is: how to better integrate green infrastructure policy and practice into and urban area? To answer this question, American Forests conducted Urban Ecosystem Analyses in more than 40 US urban areas over the last five years. With more than 700 copies of CITYgreen software in circulation, American Forests encourages communities to use a green data layer-a digital map of landcover along with CITYgreen to calculate the benefits of their urban forests for land planning.

The following case studies offer examples of how cities have strengthened their local ordinances, secured additional funding, enhanced programs and staffing, and improved communication between diverse stakeholders. In addition, there are some new ways to integrate green infrastructure into communities to help meet federal clean air and water requirements. Changing mindset does not happen overnight, but step by step, one policy, incentive, or business practice change at a time. Here are some examples.

Case Studies

Establishing Canopy Cover Goal
City of Roanoke, VA

Increasing Canopy and Cooling Parking Lots
Trees Atlanta, Atlanta, GA

Tackling Air Pollution through State Implementation Plan
Texas Forest Service and Houston Green, Houston, Texas

Riparian Buffers, Clean Water Act requirements, and Tree Preservation Code Amendments
City of Salem, OR

Future Planning
City of Charlotte and Mecklenberg County, NC

The $50 million Dollar Photos
Casey Tree Endowment Fund, Washington DC

A New Tree Ordinance, Energy and Water Conservation
City Public Service and Texas Forest Service, San Antonio, TX

Regulatory Opportunities to Integrate Green Infrastructure Planning

The current legislation favors using trees to comply with clean air and water regulations. Here's a look at a few current and potential opportunities.

EPA's Early Action Compact

EPA's Phase II Stormwater

Carbon Trading

GASB 34: Counting Trees as a Municipal Asset

Establishing Canopy Cover Goal

Roanoke, VA
Helen Smythers, Urban Forestry Planner
Charlie Blankenship, citizen activist

Less than a year after their Urban Ecosystem Analysis measured a 32% tree canopy cover, less than American Forests recommended a 40% goal for Roanoke, the City Council passed an Urban Forestry Plan as part of the city's Comprehensive Plan. The plan's top priorities are to achieve a 40% citywide tree canopy goal within 10 years and to plant enough public trees to reverse the current annual net loss. In just a year's time Helen Smythers, Urban Forestry Planner is pleased with the city's accomplishments in the first year, including revising their landscaping ordinance and zoning, better project coordination between departments, and information sharing.

[Back to Top]

Increasing Canopy and Cooling Parking Lots

Atlanta, GA
Marcia Bansley, citizen activist, Trees Atlanta

Sometimes it's not just a matter of passing new legislation, but enforcing the tree ordinance you already have.

In 1996, American Forests conducted the very first Urban Ecosystem Analysis in Atlanta in response to the city's concern about the urban heat island. Working with a meteorologist, American Forests demonstrated the direct relationship between loss of trees and increase in temperature in the city center.

Marcia Bansley, executive director of Trees Atlanta believes this study has gotten into the consciousness of Atlanta's citizens as well as city government leaders. Since the analysis was completed, developers must plant street trees in all new developments or, if that's not possible, contribute to a Tree Trust Fund. So far, the fund has $1 million for trees to be planted in other areas of the city.

One of Tree Atlanta's goals was to implement the parking lot ordinance to plant trees-on the books since 1992 but never enforced. With a grant from the Georgia Forestry Commission, American Forests used CITYgreen to model tree canopy at turner Field's parking lot, before and after Trees Atlanta planted it and then to simulate benefits over the next 20 and 30 years.

Turner Field Parking Lot (4 acres)

• Current tree canopy 5%
• Current 5% canopy+ new trees+ 30 years growth=29%
• $16,000 stormwater management benefits
• $275 annual air pollution removal benefits

If all 122 acres of surface parking lots in the Downtown Atlanta Study Area complied with the ordinance the benefits would make a tangible impact.

Downtown Atlanta Study Area Parking Lots (122 acres)

• Current tree canopy 7% +30years growth
• $491,000 stormwater management benefits
• $7,534 annual air pollution removal benefits

The results convinced the Mayor's Deputy Chief of Staff and the Commissioner of Planning to enforce the parking lot tree ordinance for the first time-and now nearby Fulton and Cobb counties have easily passed new parking lot ordinances and enforce them.

[Back to Top]

Tackling Air Pollution Through State Implementation Plan

Houston, Texas
Mickey Merritt, Regional Urban Forester, Texas Forest Service

Houston became a non-attainment area for Ozone, under the Clean Air Act, back in the 1970's and the problem has been getting worse as their tree canopy has declined-16% over the past 3 decades. Without trees to absorb air pollutants, Houston lost $38 million annually in air pollution removal services as well as $237 million in stormwater management services.

Houston Green, a coalition of 15 public agencies and non-profit organizations, was particularly interested in getting tree preservation and planting measures written into their State Implementation Plan to help meet EPA air requirements and reduce the urban heat island.

A year after the analysis was complete, voluntary tree measures were written into the 2001 State Implementation Plan. Mickey Merritt, Regional Urban Forester for the Texas Forest Service, says Houston Green's next goal is to change voluntary status to enforceable.

Overall Mickey sees subtle but distinct changes in mindset since the UEA study. He says the tree loss findings have opened doors for urban foresters to talk more with developers about trees as part of the infrastructure instead of just beautification. Examples of their progress include:

• The city passed amendments to strengthen the tree and shrub ordinance
• Harris County Flood Control has hired an urban forester and is starting a reforestation program
• Public and private community groups are talking about increasing canopy coverage for the Houston area.
• The Gulf Coast Institute, Cypress Creek Flood Control Coalition and Legacy Land Trust are using CITYgreen to assess forest benefits along creeks, in watersheds, and in conservation easements.

[Back to Top]

Riparian Buffers, Clean Water Act Requirements, and Tree Preservation Code Amendments

Salem, OR
Peter Gutowsky, Senior City Planner

In 2001, the City of Salem, Oregon requested an Urban Ecosystem Analysis, but was eager to include a green data layer of classified land cover data to determine the relative health of Salem's watersheds and riparian corridors. That is because impervious surface and canopy cover directly relate to watershed function and are critically important for salmon habitat and water quality-part of the city's responsibilities under the federal Endangered Species Act and Clean Water Act.

Salem passed its new Greenways Ordinance in 2004. It recognizes the need to preserve valuable Salmon habitat under federal wildlife protection legislation. Protection of habitat begins upstream, where urban stormwater runoff, ladened with pollutants picked up from roads, parking lots, and other impervious surfaces eventually make their way to the Willamette River. Among the ordinance provisions, all off street parking stormwater treatment facilities shall be designed to remove pollutants to the "maximum extent practicable". Trees are listed as a mitigation measure to reduce impervious surface area, intercept rainfall, detain flows, and dissipate runoff velocity. In addition to recognizing trees stormwater runoff reduction ecosystem services, Salem’s ordinance also recognizes the importance of shading impervious surfaces that would otherwise heat stormwater that enters the river and harm aquatic life. The ordinance requires that trees are to be planted so their canopy shades 50% of the parking lot after 15 years of growth. Of course cooler parking lots and shading cars provides direct human comfort as well.

[Back to Top]

Future Planning

Mecklenberg County, NC
Laura Brewer, Charlotte City Planner

In North Carolina, Mayor Patrick McCory is passionate about Charlotte's trees and is a leader in promoting green infrastructure as the region explodes in growth. The area lost 22% in tree canopy and also in open space. The region stands to lose $6 billion in federal funding if it falls into non-attainment under the Clean Air Act.

Laura Brewer, urban forester in the Engineering Department says the city is proud of their tree ordinance, which recently added new residential tree protections. She thinks that if the city didn't have a good ordinance, the findings of the UEA would have been drastically worse. With the new green data layer, she can now test the current tree ordinance to see if its canopy percentages and planting meeting their environmental requirements. This will give ammunition to beef up their ordinance if need be.

[Back to Top]

The $50 Million Dollar Photos

Washington DC
Barbara Deutsch, Casey Tree Endowment Fund

Sadly, The District of Columbia, called the city of trees, had lost 64% of its tree cover from 1985 to 1997. The news, covered in the Washington Post, caught everyone's attention. The Urban Ecosystem Analysis, later dubbed "The $50 million dollar photos" mobilized citizens, Mayor Anthony Williams, and Betty B, Casey, to re-tree DC.

The analysis caught the attention of Mrs. Casey's Foundation, which donated $50 million for the improvement and revitalization of Washington's trees. The Casey Tree Endowment Fund was born. The city hired a professional urban forester for the first time in many years, increased tree planting, and drafted and approved its first tree ordinance.

In the summer of 2002, Casey Trees led a citizen-based inventory of every street tree. The GIS-based inventory data will be used to calculate the value of ecosystem services. Casey Trees also launched a DC Citizen Forester Program.

[Back to Top]

A New Tree Ordinance, Energy and Water Conservation

San Antonio, TX
Jenna Terrez, Environmental Analyst, City Public Service
Mark Peterson, Regional Urban Forester, Texas Forest Service

San Antonio's 22% canopy loss between 1985 and 2001 re-energized the urgency for the city to finalize and pass a revised Tree Preservation Ordinance that had been intensively reviewed and negotiated for three years.

San Antonio Mayor Ed Garza encouraged the city's residents to take a close look at the recent numbers from the 2002 UEA, even if they were troubling. "It's easier for citizens to understand the need for regulatory changes when we have real numbers and research to back them up."

In Phase 2, American Forests created a 'green data layer' for the city to use as a planning tool. San Antonio's precious Edward's Aquifer provides the city's water and the groundwater recharge zone is under rapid development. Mark Peterson, regional urban forester for the Texas Forest Service, envisions the City's Planning Department using the green data layer to identify, purchase, and protect significant ecological areas within these recharge zones and in determining optimal tree canopy levels during development.

At City Public Service, San Antonio's Utility Company, Jenna Terrez, Environmental Analyst will use the digital data to prioritize planting areas for CPS's new Green Shade Program. She says that people need to see how their tree planting efforts impact the environment in real and tangible savings.

"Flooding in San Antonio is an age-old issue," says Carol Haywood, a planner with San Antonio's neighborhood and urban design department who is eyeing the green data layer's public education potential. "Most folks think we need more concrete culverts to simply whisk the water away as fast as possible. We will use this green data layer to model and demonstrate the ability of trees to perform a similar function without adding new concrete."

Phase 1: Tree loss trends

• 22% tree canopy decline from 1985-2001
• Loss of $9 million in air pollution mitigation per year.
• Loss of $146 million in storm water management services.
• Loss of $17.7 million in residential summer energy services per year

Phase 2: Green Data Layer (future implementation)

• Protect significant ecological areas within ground water recharge zones
• Determine optimal tree canopy cover in new development
• Prioritize planting for energy conservation
• Improve flood control while reducing gray infrastructure

Regulatory Opportunities to Integrate Green Infrastructure Planning.

[Back to Top]

On the Books right now:
EPA's Early Action Compact
Currently, many regions in the country exceed Federal Clean Air Act limits, especially for ozone. EPA has established an Early Action Compact, which allow regions to implement local solutions instead of one-size-fits-all national-level programs. By taking an active role in improving their air quality, participating counties avoid standard non-attainment penalties such as the withholding of federal transportation funds.

For example, EPA requires participating counties to implement air quality programs that are 1) quantifiable, 2) enforceable, and 3) permanent. Dorothy Birch of the Alamo Area Council of Governments in the San Antonio region, explains that the green data layer in San Antonio will play an integral role in the design and evaluation of these Early Action Compact programs, because tree benefits can be quantified.

[Back to Top]

EPA's Phase II stormwater
The recent Phase II of the Federal Clean Water Act "offers the best regulatory structure for recognizing urban forestry programs that increase tree canopy cover" according to Lisa Nisenson, US Environmental Protection Agency (EPA).

In 1999, EPA recognized urban runoff as a major (non-point source) contributor to water pollution. Under a regulatory program of the Clean Water Act, cities over 250,000 in population were required to file stormwater management plans. This year, smaller cities of 100,000-250,000 in population had to comply under Phase II.

EPA recognizes trees in their model stormwater permit guidance under Phase II, especially for post-construction runoff control. Communities have five years to develop and implement their stormwater management plans. A key requirement of Phase II is that plans must have measureable goals. EPA developed a more comprehensive way to measure and regulate different water pollutants called, Total Maximum Daily Loads or TMDLs. The new CITYgreen for ArcGIS uses this measurement in its calculations of stormater benefits of trees.

[Back to Top]

On the Cutting Edge:
Carbon Trading
The ability of trees to store and sequester carbon is now making noise in Congress. A bill introduced in the U.S. Senate would establish a market-based trading system. Energy producers, such as power plants could meet part of their air pollution reduction requirement by obtaining "credits" from those who have forests or agricultural land to sequester carbon from the atmosphere.

[Back to Top]

GASB 34: Counting Trees as a Municipal Asset
Perhaps the most cutting edge idea in institutionalizing green infrastructure is in GASB 34. GASB 34 stands for Government Accounting Standards Board Statement 34. Traditionally, state and local governments reported their infrastructure assets, such as roads, bridges, dams, and vehicles, on a cost basis reported in the year the asset was acquired or built.

With the new GASB 34 rule, set to begin in 2004, governments will have to report their assets on an accrual basis-that is to account for the monetary value of their infrastructure assets throughout their lifespans and factor in depreciation. Here's where trees come in: Calculating the monetary value of trees for improving air and can be worth billions in a city. Counting urban forests as assets boosts a government's financial performance and improves bond rating. The Center for Neighborhood Technology in New York is starting to do a pilot study to explore the feasibility of this. Watch for this to develop.

[Back to Top]