A plain New England autumn is an oxymoron. It’s always beautiful.
And always different. A maple that’s crimson one year may be cider brown the next. But down the road, around the corner, it’s salmon and gold. You want to live somewhere else?
Connecticut’s mix of southern and northern forests means it’s never even uniform.
“The swamps turn color first,” said Jeff Ward, forester with the Connecticut Agricultural Extension Service in New Haven. “Then, it’s as if it moves up the slopes, then back down.”
This year, people are seeing some trees turning color and shedding their leaves early, thanks mostly to a hot, dry September.
“What I’m seeing is the result of localized drought,” said Geordie Elkins, operations director at Highstead Arboretum in Redding. “It’s a patchwork of spotty damage. Some of the dogwoods are completely gone.”
The oaks are yet to make their move to russet. Because of the emerald ash borer, their claret foliage may be missing from the landscape.
So the idea of a peak weekend — often said to be the Columbus Day weekend — may be stretched out.
But first, the obligatory Botany 101 lesson.
Leaves are green because they contain chlorophyll. It’s the green pigment that allows plants, and even algae and cyanobacteria, to convert sunlight, water and carbon dioxide into the sugars that feed the plant.
As autumn approaches, hardwoods — knowing winter’s coming — are hardwired to shed their leaves to conserve energy.
They produce a layer of thickened cells where branches meet leaf stems. That cuts off the supply of nutrients and water to the leaves, and traps the sugars the leaves have remaining in their tissue.
Trees stop making chlorophyll. When that bright green pigment goes away, other colors that have been in the leaves all along — yellow carotenes and red anthocyanins — get to shine. The sugars left in the leaves make these colors vivid.
Thomas Philbrick, a botanist and professor of biologic and environmental science at Western Connecticut State University in Danbury, said these are uniform changes.
“The change in day length happens every year,” he said.
What’s not uniform is the weather.
“Temperature is ambiguous,” Philbrick said.
This year, the late summer turned hot. Gary Lessor, director of The Weather Center at Western, said September was 1.6 degrees F. higher than average.
It was also really dry. Matt Spies of Brookfield, state coordinator of the Community Collaborative Rain Snow and Hail Network — CoCoRaHS, the national network of volunteers that collects daily precipitation data — said that ordinarily, Connecticut gets about four inches of rain a month.
But after a very wet spring and a healthy early summer, things changed.
“The spigot turned off at the end of July,” Spies said.
Thundershowers in August gave some towns more rain than others.
But for September, towns around Danbury got an inch or less of rain. In lower Fairfield County, it was up to 1.5 inches. New Milford got two inches — still two inches below normal.
As a result, drought-stressed trees started shedding leaves earlier than usual.
“You could see it with maples and tulip poplars and black birches,” said Matt Bartelme, an arborist and owner of Bart’s Tree Service in Danbury.
“A lot of the older trees will drop first,” said Sam Gentile, an arborist and owner of Gentile’s Tree Care in New Milford, of the dry weather. “Unfortunately, a lot of our swamp maples and sugar maples are older trees.”
And, Bartelme said, the wet spring may have triggered fungal diseases in the trees, resulting in dry, spotty leaves now.
What people don’t know is how climate change may affect the fall foliage season.
Howard Neufeld, a professor of physiological plant ecology at Appalachia State University in Boone, N.C., said that if the climate steadily gets warmer, that may change what the fall foliage looks like.
Drought can make leaves turn early. Wet, cloudy days cut down on photosynthesis, and the development of anthocyanins that produce red leaves in the fall.
And a steady supply of warm days without cool autumnal nights delays the turn of the leaves altogether.
What we may end up with, Neufeld said, is the loss of a synchronized fall foliage season, with trees flaring in patches, rather than in a grand, orchestrated swoop.
“Every season is surprising now,” Neufeld said of the changes a warming climate brings. “So trying to predict what the trees will do is kind of hard.”