Region's trees primed for perfect fall foliage color

Rob Haneise

The hills and valleys of the region are ablaze with prime fall foliage color thanks to a near-perfect lineup of fall weather.

Unlike the previous two years where summer drought or severe early cold snaps withered leaves and prematurely denuded the autumn landscape, this year's foliage is remarkable, some say.

"This is probably one of the best years," said Scott LaFleur, horticulture and botanic garden director for the New England Wildflower Society and Garden in the Woods in Framingham. "From now through the next week or two we will be in peak foliage."

Several elements for great foliage occurred this season.

First, trees were well-hydrated with plenty of late summer and early fall rain with mild temperatures. According to National Weather Service archives, Boston had 2.98 inches above normal rainfall for September with slightly above normal temperatures. Worcester had 4.95 inches above normal rainfall with temperatures averaging more than 3 degrees above normal.

And then the deluge shut off for October. Fall foliage needs a combination of warm October days with cool nights. The lack of storms helps trees keep their leaves longer. Weather archives show that rainfall was about 1.5 inches below normal for the month of October thus far in the region with temperatures 1.4 to 3 degrees above normal.

Last year's severe summer and fall drought caused many trees to start dropping leaves in late August before any color change could occur.

Nature handles some of the change regardless of the weather.

"What really triggers the changing is the shortening of the day," said LaFleur.

LaFleur explained that the leaves don't so much change as simply reveal the colors that have been masked all year long by green chlorophyl. As the days shorten and the trees stop actively growing, the other colors in the leaves become visible when chlorophyl fades. In maples, that means brilliant reds, oranges and yellows.

Many trees in low-lying areas and swamps have already dropped their leaves. As the foliage season progresses, color tends to make its way up the hills in MetroWest.

The high marks for foliage are not unanimous.

"Only about half of the trees have changed colors, there's still a lot of green out there," said Peggy Hobbs, administrative officer for the Eastern Massachusetts National Wildlife Refuge Complex at Great Meadows National Wildlife Refuge in Sudbury.

Hobbs said it seemed like it has been too warm for the leaves to change color.

Some scientists have pointed to global warming as a threat to New England foliage. A warmer climate could cut into cool, crisp nights and also drive sugar maples farther north, LaFleur said.

If the sugar maples move north over time, fall foliage could be dominated by the muted browns of oak leaves.

"It could change our overall tapestry of colors," LaFleur said.

Rob Haneisen can be reached at or 508-626-3882.

MetroWest Daily News