Benefits of Aberdeen's street trees demonstrated by student's survey

The survey result has received much praise from Aberdeen city officials.

Walking around downtown Aberdeen, analyzing trees along its streets seemed like a simple capstone project for Alexander Usselman's senior year at the Science and Mathematics Academy at Aberdeen High School.

Measuring 300 trees over six months, however, gave him a healthy respect for those who study plants for a living. He worked from last October through early spring, going out three to four times per week, for one to three hours each of those days.

He said he did not have an interest in agriculture or environmental science before doing his senior project, which involved cataloging Aberdeen's street trees and assessing their impact on local air pollution.

"I can respect scientists a lot more at this point," Usselman, 19, said in a recent interview. "They do a lot of work to do what they do."

The survey result, which was presented for his senior capstone project in late May, has received much praise from Aberdeen city officials.

After viewing the project during the Science and Mathematics Academy's annual gallery walk program last spring, Mayor Patrick McGrady invited Usselman to attend the June 6 city council meeting and talk about the city's trees.

Usselman told city officials that his project was designed to calculate how much the trees along Aberdeen's streets and sidewalks "benefit the city overall and what improvements we could possibly make with the sample inventory," according to a video of the council meeting posted on the city's website.

The benefits of street trees include intercepting rainfall to prevent stormwater runoff, absorbing pollutants such as carbon monoxide, ozone and particulate matter, reduce air temperatures, provide shade and help cool down nearby buildings, Usselman told city leaders.

He stressed the values of species diversity as well as age diversity.

"Younger trees are able to mature and replace the older trees as they may begin to die out," Usselman said. "It would be a good idea to continue planting younger trees so we can continue with that cycle."

His study area included downtown and residential areas between Route 40 and the railroad tracks. He cataloged the species, height, diameter at breast height, the size of the tree canopy and the amount of live canopy.

He then put the data into the U.S. Forest Service's online i-Tree program to measure each tree's health benefits.

The most common species, among the 300 trees in Usselman's sample, were sweet gums, Callery pears, silver maples, willow oaks and Norway spruces. He said the oaks are the native trees that are most beneficial for public health, and the Norway spruces are the most beneficial non-native species.

Usselman said the Callery pears are the least beneficial, and the Forest Service categorizes them as an invasive species.

"It spreads very easily," he said of the pear tree. "It doesn't provide too many benefits. so that's a kind of tree that people are thinking about removing; that's just something that's interesting to look into."

Usselman noted he could accurately measure the trees' diameter, but he had to estimate other aspects such as height and canopy size because of limited resources.

"This was a simple sample, a small sample," he told city officials. "What I would recommend is to gather a group of official foresters and people who are more skilled in tree measuring to conduct a more complete survey of the entire Aberdeen urban area."

Just the sheer magnitude of "counting 300 trees" impressed McGrady, who posed for a photograph with Usselman and his mother, Michele, afterward.

Usselman said he had support from his mother, who provided transportation for some of his surveys, and from his faculty adviser, Yvonne Gabriel.

The Aberdeen High Science and Mathematics Academy is a magnet program open to students from throughout Harford County. Usselman grew up in Forest Hill, and attended North Harford Elementary School and North Harford Middle School

Following his graduation from AHS on May 31, Usselman is a first-year student at the UMBC in Catonsville.

He is leaning toward graphic arts as his college major, citing his passion for drawing comics, or studying chemistry.

"I still have a choice in what I want to do in life between science and art," he said.

"The SMA is an asset to the city, as well as an opportunity for high school-age kids to connect with real-life applications," McGrady said recently.

Science and Math Academy seniors create projects on a range of topics, and McGrady noted Usselman's topic was "relatable" for the public.

"I try to include as much of the public as we can in the council meetings," the mayor said.

McGrady noted the information Usselman provided to the council in June was "very interesting," but it has not yet been used by city officials.

"Those kinds of figures are useful in terms of community redevelopment," McGrady said. "We're not a new community – if you move to Aberdeen, we have 100 years of tree growth to experience."

Aberdeen was incorporated as a city in 1892, and many of its trees date back decades, as they have not been cut down as in other parts of Harford County, to make way for development, according to the mayor.

"These old trees that we have, have seen a lot of history," McGrady said.

Usselman said his presentation to the city council was "an interesting experience."

"I got to learn some things about how the city government works," he said.

Usselman said he thinks about his SMA project when sees a tree on the UMBC campus and recognizes the species.

"In an urban environment, trees are quite important," he said.

He noted his experience at the SMA was much harder than expected, but he does not regret being in the program because he was better prepared for college. He was also able to take a variety of science and math electives while in high school, such as organic chemistry, linear algebra, genetics, robotics, even pre-engineering.

"It was a good decision," he said. "It challenged me; it made me learn what science is really about."

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