Other than as hammock poles and hiding spots for the elusive albino squirrel, the nearly 5,000 trees on the UT main campus are useful for helping filter the air and keep buildings cool with shade, and a new interactive website can now show curious Longhorns an exact dollar amount for the benefits their favorite tree provides.
In January, UT landscape services launched myTreeKeeper, a website that displays statistics for almost every individual tree on campus using data collected over the past year. The site is interactive, allowing a user to zoom in to any location on campus and learn about the benefits of individual trees or to search for trees by location, size or species.
“For most people that look at it, at first it’s not something that sparks their interest, but if you take a little time looking at what it’s saying, it’s pretty interesting,” urban forestry assistant manager Jim Carse said. “Typically people look at a tree and don’t think past what it looks like, but it’s more than just aesthetics.”
The site is part of a three-part project to inventory and store data on campus trees; the other two pieces were software in the landscape services’ office to edit and update information on trees, and a mobile website allowing landscapers to update information and submit work requests while in the field, according to Carse.
“Every tree on campus is there, and you can go and search it, and we have the way to track all of our maintenance, track all of our plantings, track all of our removals, in a much easier way than we once did,” he said. “It enables us to track what we do better, and it enables us to put budget dollars where they should be.”
Carse said they wanted the project to allow data to be accessible to the campus community.
“We really wanted the place where we could put the data where people can see it and use it as a learning tool,” he said. “We get quite a few requests every year, where there might be classes at UT that want to learn more about the trees or learn about a particular species or a particular spot on campus.”
The project employed the help of Davey Resource Group as a contractor, and in the end, it cost around $45,000. This price included the inventory software and a report detailing the condition of the trees inventoried. Carse said the project was money well spent because the report and the process of inspecting all of the trees helped landscape services find and take care of urgent tree issues, such as broken or decayed limbs, that had gone unnoticed.
“There’s no way that our 70-odd landscape staff was going to spot everything in all the trees on campus,” Carse said. “This was a way to get a separate pair of eyes that looked at nothing but tree concerns and tree issues around campus. At the very minimum, it created a safer environment.”
The Value of an Urban Tree
Urban forests, or the collection of trees and other vegetation in a city, benefit a city through numerous services, such as reducing noise from roads, preventing soil erosion from rainwater and filtering pollutants out of the air and water, Carse said. The myTreeKeeper website calculates benefits from a total of 4,830 trees, which provide the UT campus with nearly $550,000 of annual benefits in ecological services and property values.
Trees can also take carbon dioxide out of the atmosphere, in a process generally called carbon sequestration. Vegetation such as trees and grasslands plants remove carbon from the atmosphere and store it in their tissues, UT landscape architecture professor Jason Sowell said. UT’s trees provide nearly $14,000 in greenhouse gas sequestration benefits according to myTreeKeeper.
“Given the fact that there is a concern for the amount of carbon dioxide in the atmosphere and the amount of carbon dioxide that our primary energy sources and vehicular transportation produce, we need some means of reducing the amount of carbon in the atmosphere in order to mitigate these impacts,” Sowell said. “That’s something that the [myTreeKeeper] tool begins to provide monetary value to as a way to suggest just how important these are, not only as very beautiful spaces but also for what they provide the campus at a range of different scales.”
Trees have also been shown to correlate with positive mental and physical health, said Emily King, urban forestry program manager for the city of Austin. According to a book by researchers from the University of Copenhagen titled “Forests, Trees and Human Health,” trees can reduce stress in urban environments and provide spaces for relaxation and physical exercise.
“There’s this amazingly big category of human health benefits that trees provide,” King said. “I think it’s kind of important to take a deep breath and stand back and say, there’s something about big trees that cause people to feel awe and wonder. Trees are just neat things to have around, like really big old ones that have survived for centuries and have seen Texas history.”
Campus Environmental Center co-director and government junior James Collins said the urban forest on campus, which includes a lot of native Texas trees and provides habitat for local wildlife, contributes to UT’s identity as a campus.
“We have those really big oaks in the mall, those are really iconic to our campus,” he said. “Other than enjoying the ecosystem services they provide for us, the bit of nature that infuses into our campus can give us a balance between a really fast-paced urban lifestyle and one that interacts more with the natural environment.”
The Urban Heat Island Effect and the City of Austin
Trees can also help cool the city by fighting a phenomenon known as the urban heat island effect. Cities are generally hotter than the surrounding countryside because they are constructed mainly from materials such as concrete and asphalt that absorb heat from the sun and reflect it back into the air, Sowell said.
“What this tends to do, which I think anyone who has stood in the middle of an asphalt parking lot in Austin during August can attest to, that radiation is both uncomfortable for us as humans, and it begins to exacerbate microclimate issues in our built environment,” he said.
Trees cool the city by creating shade and reducing the amount of heat absorbed by buildings and pavement.
One effort to grow the urban forest and mitigate the urban heat island effect is a collaboration between the city of Austin, local tree nonprofit TreeFolks and Austin Energy called NeighborWoods. NeighborWoods is a program funded by Austin Energy where the city of Austin and TreeFolks give away about 4,200 free trees annually during Texas’ tree planting season from October through March to Austin residents to plant on their property in order to provide shade, TreeFolks community engagement manager Nell Newton said.
“It was a program that Austin Energy decided to do to try and increase our canopy, because a more dense urban canopy means a cooler city, and a cooler city means less need for electric energy and less air conditioning,” she said.
Trees can save energy in this way by shading buildings, according to Carse. During the summer, trees can reduce electricity usage by shielding the building from the sun and reduce the need for air conditioning.
NeighborWoods started as a project in the Austin Parks and Recreation department in the 90s, but it wasn’t very efficient, said Leah Haynie, the environmental program coordinator in the city of Austin’s community tree preservation division who used to work in the NeighborWoods program with Austin Energy. Austin Energy led a task force to reduce the urban heat island effect in 2000, and in order to save electricity during peak demand time and help reduce urban heat they began funding NeighborWoods.
TreeFolks executive director Thais Perkins said trees in Texas cities have a difficult time growing well because of this urban heat island effect combined with the naturally dry and hot climate of Texas.
“The same tree that might be a 10- or 15-year-old tree somewhere like Oregon might be a 50- or even 100-year-old tree here because it grows so slowly,” she said. “When you remove an older tree in Austin, it takes that much longer to get it back, so it’s important to preserve the trees that we have in addition to planting more to replace the ones that we’re losing.”
Due to climate change, the city landscape will only become more hostile to trees in the future; according to a 2014 report for the city of Austin by climatologist Katharine Hayhoe, summer maximum temperatures are predicted to increase by between 3.5 and 6 degrees Fahrenheit by the middle of this century, and days that reach a temperature of 110 degrees Fahrenheit, which are extremely rare, could be as common as from two every five years to up to 12 per year.
“In many ways, until recently [trees] haven’t been given much regard to why they’re important,” Sowell said. “But with climate change and a concern for the campus’ sustainability performance over time, factors [such as creating shade and sequestering carbon] are increasingly more important to consider more holistically for the landscape itself.”
In order to address these challenges, the city of Austin adopted an urban forestry master plan in 2014. The plan sets goals for the city to achieve in urban forestry and gives direction for what to do next, King said.
“These goals were set through getting priorities from people who work for the city of Austin, as well as groups that we consider partners, as well as the community,” King said. “It is a document that was not created in a vacuum, it gave the community an opportunity to weigh in priorities. It was really filling a void, because we did not have anything like that prior.”
Since the adoption of the master plan, the Texas Forest Service at Texas A&M University collaborated with the US Forest Service to participate in a nationwide federal project called the Urban Forest Inventory and Analysis, or Urban FIA. The Urban FIA collected even more data than was available in 2014 about the Austin urban forest, King said.
In 2016, the Texas Forest Service took the data from the Urban FIA report and created an interactive website, similar to UT’s myTreeKeeper, called My City’s Trees that shows the annual benefit of urban trees. Many of the cities across the country who participated in the Urban FIA will be added to the application in the future, including San Antonio and Houston, once their data is complete, according to Brad Hamel, central Texas regional urban forester with the Texas Forest Service.
“The Urban FIA report is a static look at trees in Austin and the benefits they provide,” Hamel said in an email. “My City’s Trees allow the user to look at particular trees and benefits, creating a customization that the report does not have. The interactive website, for example, can allow a user to look at how much carbon is sequestered by each major species.”
The My City’s Trees website also breaks down Austin by area of city growth and can show how much the city, and the amount of trees counted towards an urban forest, has expanded since 1950. Perkins said one of the main challenges that urban forestry faces in Austin is that the city is expanding rapidly. According to data from the U.S. Census Bureau, Austin’s population has increased by an average of 2.3 percent each year since 2000.
“The quicker you grow and develop, the more of the urban forest you remove just to clear away for housing,” Perkins said. “This city has very good tree protection measures, we’re actually a model in the nation for that, but even so, there’s an awful lot of the canopy that gets removed as we expand.”
When it comes to development and removing trees, Carse said cutting down a number of individual trees that each provide a small benefit can add up to a big impact.
“I know I’m not going to be able to save every tree, but we need to do a better job of planning, we need to do a better job of using new construction techniques, we need to do a better job of preserving trees on construction sites,” he said. “We’re doing some really good stuff, but we need to keep it going and we need to up the ante. We just need to remember where we came from and what our task is with our time on this Earth, and that is to be good stewards of our natural resources.”