Fall foliage means it's about to get colorful
BUCYRUS — Wind is the real enemy.
A perfect fall foliage season can disappear in a single day should gusty winds decide to blow in. All those perfect weeks of warm, sunny days and cool, clear nights will be for naught if a strong cold front pushes through.
Recent days have indeed been blustery across north central Ohio, as well as the rest of the state, but timing is everything, and in most cases the veins tasked with carrying fluids into our trees' leaves haven't closed off yet. The leaves aren't ready to fall. But that will soon change.
"The leaves are on schedule. We're starting to see some color in the northern and central parts of the state. You can pretty much divide the state in thirds. The northern part of the state should see color by the end of next week," said Casey Burdick, fall color forester for the Ohio Department of Natural Resources.
Across most of Ohio, fall colors peak around the third week of October, but intensities can vary widely from region to region, even from one side of the road to the other. Trees, of course, are stationary, and they can be profoundly affected by their vicinity's micro-climate. That, inevitably, will affect how bright their leaves become in the fall.
"The first trees to turn are generally in urban areas and along roadways because they're more stressed. They have to put up with a lot more direct weather conditions as well as salt impaction," Burdick said.
There are so many weather variables that go into whether the fall foliage will ultimately deliver that no two seasons are alike. And because weather conditions can vary so much from place to place, no two regions can be expected to exhibit the same amount of color. But overall, Burdick expects this fall's leaves in Ohio to be vibrant.
"The temperatures in September and October are very important. We're settling in very nice right now," she said.
For most of the state, the past summer's temperatures were largely seasonal, followed by nearly a week of hot temperatures around Labor Day. Leaf color is really only affected by temperatures once chlorophyll production starts to slow down, however.
More than anything, it's the declining daylight that causes the great autumn color show each year. With less sunshine, leaves can't keep up their manufacture of the green chlorophyll pigment. Once that declines, the yellow carotenoids that were present in the leaves all along emerge. If atmospheric conditions are favorable, leaves will then also start producing anthocyanin, which gives leaves that bright red color.
Precipitation levels throughout the growing season can affect fall foliage, too. This year, Ohio's trees received more than enough rain in June and the first half of July, followed by little precipitation for the rest of the summer. But Burdick doesn't think water stresses will be a major issue.
"I think trees had a very good growing season, and a lot of them are pretty healthy. They should hold on to their leaves for a while," she said.
Because August and September were so dry, many tree species such as maples and especially black walnuts didn't contract anthracnose, a fungal disease. If they do, walnut trees can be bare by Labor Day.
"When you have a wet, late summer, they will drop their leaves early," Burdick said.
Black walnut leaves only turn a bland yellow in the fall, but this year they will be around, making their contribution to the annual pageantry of colors.
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