Why the early change in trees?

August 20, 2008

It's still summer, but if you look closely at a few of the trees near Villanova you can catch a glimpse of fall. Some of the foliage is already starting to change color.

So, are we in for an early season of brilliant rich colors? Well, Dr. Ernie Schuyler, a botanist at the Academy of Natural Sciences, says not so fast.

"This is something we see often in late summer when we have a dry spell," said Dr. Schuyler. "I think this is a temporary thing. I don't think it indicates that we're going to have an early season for change in colors."

So far, we've had a warm, dry spring and summer with rainfall nearly 2 inches below average. That's why some leaves are changing. But, it's early. If we hit a cloudy, rainy period late September into October, we may see little color change at all!

Weather is a factor in fall foliage, but the constant is the change in daylight near autumn - as the length of night increases the production of chlorophyll decreases. Chlorophyll makes the leaves look green. When you have no chlorophyll you can see the beautiful colors underneath.

Here's the bottom line: For the most beautiful colors we'd like to get a bit more rain now. Then in fall we need warm, sunny days with cool crisp nights.

Expect the colors to change sometime in October.

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