HOUGHTON -- Every year around the time the calendar flips into October, the forests of Upper Michigan become ablaze with color. And thanks to the decidious diversity we have, we see everything from golden yellows to deep reds.
"The sugar maple and the red maple, the oaks get decent color, but it's really not as vivid as what the maples get, and then the aspens often will throw in a very nice yellow," said Dr. Andrew Burton from the Michigan Tech Biology Department. "Sometimes it happens a little later than for the other trees, so we kind of have a nice mix of color as we move on through the fall."
While all trees start off green thanks to chlorophyll, their chemistry changes as it drains away before winter.
"That exposes the yellow and orange pigments that were there all along--they're called carotenoids--and at the same time, in order for it to make it easier for the trees to prepare for winter and remove the nutrients that are released as the chlorophyll breaks down, they synthesize another pigment called anthocyanins, and those are the red and the purple colors we see in the fall foliage," Burton added.
The shorter days are part of what drives this in the first place; there are other major players.
If it's a warmer than usual fall, the leaves will stay on a little longer before they change color, and also, if we've had a very dry summer, especially in the second half, sometimes that can cause leaf drop to be a little earlier, and often we can get a little less color under those conditions.
But thanks to a wet September, Dr. Burton says the colors should still be brilliant.
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