Just before the latest official update on the condition of the Toomer’s Oaks was released earlier this week, Auburn horticulturist Dr. Gary Keever conducted photosynthesis measurements on the leaves of a live oak in the parking lot of Comer Hall. The idea was “to get a baseline of what (the photosynthesis levels) of a relatively healthy live oak should be” in order to compare it to the levels in the leaves of the Toomer’s Oaks. Recent developments had him hopeful they might be something close to similar, that the oaks’ ability to feed themselves was improving.
He rode the cherry picker to the top of the canopy of the oak closest to College Street. And there it was—yellowing, dead areas, signs of the herbicide damage so far absent this spring.
“The mood (of the last update) was somewhat upbeat because at that time the trees weren’t showing any signs of herbicide injury on the new growth. This has changed,” Keever said.
“It’s definitely the herbicide injury we saw last year.”
And the effect is more than aesthetic. The photosynthesis levels of the oaks? “Greatly reduced.” Some of the leaves on the oak closest to Magnolia Ave. actually returned negative readings.
“That means respiration is exceeding photosynthesis,” Keever said—and not just in the leaves showing damage.
“The leaves we tested… were healthy looking,” Keever said. “They showed no signs of herbicide poisoning.”
Keever said signs of the poisoning are “even more extensive now than it was on Monday.”
“It’s probably only going to worsen as we continue on.”
Reporting by Justin Lee.
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