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PHOTOGRAPH BY LIAO PAN, CHINA NEWS SERVICE/GETTY IMAGES
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By Robert Kunzig, Executive Editor, Environment
One reason I like the flight from Washington, D.C. to Birmingham, Alabama, aside from the fact that it takes me to my wife, is that it’s a kind of time travel. When it’s still winter in D.C., spring has sprung in Alabama. (To a transplanted northerner, it’s never really winter in Alabama.) In late fall, when the trees are already bare in the capital, the flight south rewinds the clock a bit, bringing back the colors.
That stolen time is precious these days: As the planet warms and summer gets longer, fall is getting shorter. The first appearance of fall color in maple trees now comes more than a month later than it did in the 19th century, Sarah Gibbens writes for us this week. Graduate student Alexis Garretson and George Mason University ecologist Rebecca Forkner discovered that by analyzing digitized records of thousands of leaves preserved in plant collections. But the researchers also found that a lot more leaves in recent years are damaged by drought or insects—and trees are dropping those leaves weeks earlier.
That has economic implications, because in some places fall colors are a big tourist attraction. For trees, though, the colors aren’t just decorative. They’re a sign that the trees are reabsorbing nutrients from the leaves into the wood, storing it for winter, to be ready for spring. A shorter fall could interrupt that crucial process. (Pictured above, New York’s Central Park in November.)
“While nobody wants to be the ‘sky is falling’ kind of person, we do understand these changes are the plants telling us something is not right,” Forkner told Gibbens.
One way trees are adapting to climate change, of course, is by changing where they grow. Sugar maples and other trees that turn red in fall already tend to favor the north. “Sugar maples will shift north to find cooler temperatures,” biologist Howard Neufeld told Gibbens. “Instead of Vermont maple syrup, we might have to think of Toronto maple syrup.”
“Some scientists speculate that the fall color palette could become more golden in southern latitudes,” Gibbens writes.
When we arrived home in Birmingham yesterday, the last few golden leaves were still clinging to the young maple tree in our front yard. I love that tree, but my wife suffers a lingering ambivalence: When she planted it more than a decade ago, she was expecting it to turn bright red in fall. Maybe it was the wrong variety; I don’t know much about maple trees. Or maybe our tree is just ahead of the curve.
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