The autumnal equinox was Sunday, Sept. 22, marking shorter days, longer nights and changing colors.
YPR’s Orlinda Worthington reports on the science behind the beauty of fall.
This rustling sound can be heard across the west right now as deciduous trees begin changing color and shedding leaves. For humans, it’s a spectacular sight. For trees, it marks survival.
“To say it's got a system down. It's sticking to the schedule. It's very matter of fact.
It's time to get ready for winter dormancy.”
Anthony Sammartano is an extension agent with MSU Bozeman. He serves as the horticulturist for Yellowstone county. He says the change in daylight beginning at the equinox serves as a signal to trees to wrap things up and prepare for winter.
“The leaves are made up of three main pigments that are collecting light wavelengths that they use for photosynthesis. One of the main pigments they have is chlorophyll and that reflects green and absorbs red and blue. So when we hit this time of year, it's not really wise for the trees to keep that chlorophyll, so they start to break it down. And then that reveals those other pigments that are then showing the wonderful yellows and purples and reds that we see in the fall,” Sammartano said.
Sammertano says the trees are working to close up open spots where the leaves attach to the branches before the first frost.
“There's a little bit of some regenerative tissue that the tree is trying to start to close up so that way it can seal itself off. And if a cold snap comes through and it's not fully sealed, that can kind of damage some of the leaves in the trees. And that's when you see the leaves kind of stuck on trees during the winter when they should have kind of fallen off by then,” Sammartano said.
Depending on weather patterns, the vibrant fall colors usually peak in October or maybe early depending on where you are.
“Yeah, gorgeous colors. The cottonwoods are probably my favorites right now. It's like they light up the river,” Sammartano said.
In Billings, I’m Orlinda Worthington.
Sammertano says if you see troubled trees in your yard or around town, give the extension office in your county a call for advice.
