A beetle infestation has forced the city of Columbia to remove hundreds of ash trees, which is leaving gaps in the city’s landscaping.
Beyond just appearances, though, ash trees are vital for providing tree canopies for walkways and homes. Tree canopies primarily cover parts of houses, buildings or sidewalks to provide shade, leading to a decrease in electrical bills.
“(The ash tree) was kind of an ideal landscape tree, if you wanted a big shade tree in your yard,” Dave Dittmer, the city natural resource supervisor, said. “People have been planting ash trees in their yards for a long, long time. So, there’s a high percentage of them in urban areas because of that.”
Ash trees have been ravaged by the emerald ash borer, an insect that creates an infestation of larva and hurts the tree’s vascular system. As the trees die, branches or whole trees can fall onto streets and houses, posing a danger to pedestrians and structures.
A study from Beau Brodbeck and Sharon Jean-Philippe, researchers at Auburn University and the University of Tennessee, found that 17% of tree coverage over a house is equivalent to saving $10 a month on electrical bills. More coverage leads to increased savings, according to their research.
Besides ash trees providing shade, they can help with runoff problems by absorbing water.
After the emerald ash borer was discovered in Columbia’s ash trees in 2019, the city began the tree removal process. Eric Schmittel, the city’s forester, said the problem is that it’s unclear how damaged a tree is since the infection develops from the inside and then moves out.
“We kind of tell people to look for that blonding, where you see that really light bark from old bark being peeled off,” Schmittel said. “You can see those from a distance and usually at a point where your trees are doing that, (the beetles have) been there for at least probably five or 10 years.”
Once this peeling is visible on the bark, it’s safe to know that the tree is on the verge of dying and needs to be removed because it poses a serious danger, Schmittel said.
The city plans to remove all of the ash trees within its boundaries, starting with ones that have been infested. However, if a tree is in a yard, it’s up to that household to remove the tree — not the city, which can make the process more complicated.
In the meantime, the city has come up with a longterm plan to fill some of the gaps left by the ash tree removal process.
“Every time I take down a tree, I try and know where that’s at and get on a planting list to put something back in its place,” Schmittel said, “or maybe even going in where we may have a big ash tree and planting other smaller trees underneath that so once that comes out, there’s already trees there to take over that space.”
It can take a long time for the newly planted trees to start providing the benefits of a new tree canopy, as it takes about 50 years for them to grow to that height. And for full maturity, like the ash trees that have been removed, it can take even longer, Schmittel said.
As it stands, there isn’t another short-term solution besides making sure all the ash trees are gone and putting a new tree in its place as soon as possible. But for now, local tree canopies might have to shrink in order for them to flourish in the future.