Austin – A Cooling Effect

A 2006 tree canopy analysis conducted by the city’s Watershed Protection Department revealed that approximately 32 percent of the city is shaded by trees. As explained by Leah Haynie, Austin’s Heat Island program coordinator, trees can reduce summer temperatures through shading, by absorbing solar energy and through evapotranspiration. In addition, it’s estimated that Austin’s trees have the potential to store up to 100,000 tons of CO2 per year,[1] which is why departments across Austin are focused on increasing and protecting the city’s urban forest.

“Here in Texas, we value our trees immensely for their cooling effects,” says Ray Henning, line clearance superintendent for Austin Energy, one of the largest municipal utility services in the country, serving more than 400,000 customers in the greater Austin area.[2]

Therefore, when Austin’s city council passed its Urban Heat Island Containment Policy in 2001, a program called NeighborWoods was a key part of its plans. Each year, this program, which began in Austin’s Parks and Recreation Department and is now administered through a contract with the nonprofit TreeFolks, distributes between 3,000 and 4,000 trees to Austin Energy customers for planting near the city streets in the right of way. While technically these trees are on city land, Austinites are responsible for maintaining the trees and vegetation growing there, which means that neighborhood support is a key element of the program.

Zilker Botanical Garden. Credit: Victor Ovalle/ Austin Parks and Recreation

“Upfront outreach is really helpful to having success for the program,” says April Rose, executive director of TreeFolks. “Getting someone in front of neighborhood groups talking with them about why it’s important to plant street trees and what it can do for energy, ambient air temperature, property values, wildlife, etc., can get the community supportive of the program and excited about the opportunity to receive free street trees.”

Beyond NeighborWoods, TreeFolks has a variety of other programs to increase tree canopy, including Sapling Days, which are held each fall. On these select days, approximately 3,000 tree saplings are given away to Austin-area residents for planting on their private property, as much of the available space for expanding the city’s urban forest is available on homeowners’ land.

Another way the city expands the tree canopy on private land is through its Austin Community Trees program, a partnership among neighborhoods, Austin’s Planning and Development Review Department, Parks and Recreation Department and Austin Energy. Through this program, the city offers 10 species of large shade and small understory trees for planting on private property in neighborhoods with low tree canopies. This program specifically aims to engage neighborhoods in greening the city.

Rose says that one of the most helpful things to urban forest work in the city is “the general spirit of volunteerism and the grassroots energy that is part of the Austin culture. People really want to get involved and support urban-tree causes. We couldn’t do all that we do without the thousands of volunteers that we engage with every year and the support of the business community.”

Sometimes, though, especially in downtown spaces, trees may not be a feasible solution to urban heat island reduction, so in 2009, the Austin City Council passed a resolution to create a green roof stakeholder group to “explore the feasibility of offering energy and stormwater credits and other incentives, based on performance, to encourage the creation of green roofs in the city.”[3]

A year later, in August 2010, the Green Roof Advisory Group submitted a Five-Year Policy Implementation Plan to the City Council[4] and requested an extension — which the council granted[5] — to initiate the implementation of the green roofs plan. Since then, the group has completed a downtown density bonus proposal, developed green roof performance standards and launched the program on the city’s website. Now, city staff are writing the code for incorporating performance standards into building practices.[6]

Beyond planting trees and greening roofs, the city also has a Great Streets program, which is designed to improve the quality of downtown streets and sidewalks. Great Streets works with private developers to create streetscapes that go above and beyond the city’s minimum requirements. To encourage private developers to improve their streetscape plans, the city offers financial assistance to help offset the costs of streetscape work beyond the city’s minimum standards. In addition, when new lane miles are constructed, code requirements identify that one percent of the project’s costs must be dedicated to incorporating and caring for trees.

 

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References

[1] City of Austin Office of Sustainability. Climate Action Report 2011-2012. http://issuu.com/austinclimateprotection/docs/city_of_austin_2010-2011_climate_action_report (accessed Aug. 16, 2012).

[2]Austin Energy. About Us. Company Profile. http://www.austinenergy.com/About%20Us/Company%20Profile/index.htm (accessed Aug. 16, 2012).

[3]Austin City Council. Resolution No. 20090827-057. Adopted Aug. 27, 2009.

[4] City of Austin Office of Sustainability. Green Roof Advisory Group Report to Austin City Council October 28, 2010. http://www.austintexas.gov/sites/default/files/files/Sustainability/Green_Roof/2010_GRAG_Report_to_Council.pdf (accessed Aug. 16, 2012).

[5] Austin City Council. Resolution No. 20101104-023. Adopted Nov. 4, 2010.

[6] City of Austin Office of Sustainability. Green Roofs. http://www.austintexas.gov/department/green-roofs (accessed Aug. 16, 2012).