Good Question: Why Are So Many Leaves Left On The Trees?
MINNEAPOLIS (WCCO) – Normally, on Halloween kids are trudging through piles of leaves. But this year, we haven’t even reached the peak for fall colors in the Twin Cities. So, why are so many leaves still on the trees?
According to Ken Hollman of the Minn. Department of Natural Resources, the Twin Cities area is between 50-75% for peak falls colors.
“I’d say we’re a week or two behind,” Hollman said.
He says our later fall colors don’t have much to do with the late spring, but rather the drought we’ve experienced across much of the state for the past two years.
“Trees depend on water and nutrients in the ground that they take up their roots to build and create the chlorophyll and other chemicals that contain the colors,” he said.
Hollman says the lack of water to the trees during the growing season has delayed the development of an abscission layer – a layer of cells that develops where the leaf stem is attached to the branch.
Once those cells develop, usually as the days gets shorter, the leaf breaks away from the tree.
“So, we have leaves hanging on the trees,” he said.
Holman says even our rainy spring didn’t outweigh the effects of the drought over the past two years. He adds that our relatively warmer fall has also pushed back the colors.
The majority of Minnesota is past peak. Southern Minnesota and the Twin Cities are about halfway there. Holman says some of the best color – especially for oaks – is yet to come. And expect big changes by mid-November.
“They’ll eventually change,” Hollman said. “They’ve just been confused by the weather.”