The period of peak foliage color may be nearing an end, but now is the time to catch it while you can.
According to the Massachusetts Office of Travel and Tourism, much of the Pioneer Valley is still at its peak coloration, though some spots are beyond peak and others still contain green. The Berkshires have already experienced significant leaf dropping, but some areas in central Massachusetts, including Worcester County, are also at peak color.
According to the MOTT, foliage period begins at about mid- to late-September and ends in mid- to late-October.
Bernard Rubinstein, professor emeritus of biology at the University of Massachusetts, said one of the main factors for change in leaf color is day length, which shortens at the same rate every year, meaning that we can expect leaves to reach their peak coloration at about the middle of October.
Matthew Kelty, associate professor of forestry at UMass, noted that this year’s foliage period has been close to normal in terms of leaf color, though it may have been slightly more yellow and less reddish than in previous years.
According to Kelty, autumn this year was both warmer and wetter than usual, and that delayed the color change in leaves. He said the weather allowed the leaves to function longer and maintain their chlorophyll, the leaves’ green pigment due to granular matter formed in their cells.
“Because the leaves were healthy and more vigorous, that meant that the chlorophyll didn’t break down as early and it stayed green for a longer period,” Kelty said. “That little extra warmth and rainfall just delayed it for a few days … As Autumn comes on, the chlorophyll degrades, that’s why you can see yellow in generally any leaf.”
Chlorophyll is what makes the leaf function during the process of photosynthesis, he said. As day length becomes shorter and the weather gets colder, the leaf’s chlorophyll breaks down and its yellow pigment, which is normally dominated by the more intense green, becomes visible.
According to Kelty, green and yellow pigments can be found in any leaf’s chloroplasts all year long. But he added that some trees produce red, orange, or purplish leaf color.
“It depends on the species and the general vigor of the tree as to how red it gets,” he said. “There are variations among the individual trees of each species. Not every sugar maple looks the same.”
According to Kelty, the red maple got its name due to the fact that it’s leaves turn brilliantly red during foliage season. The hickory is an example of a tree that’s leaves turn only yellow.
According to Dr. John O’Keefe, coordinator of The Fisher Museum at Harvard Forest, last year was the latest foliage display of 11 seasons on record. O’Keefe, who has done extensive research on autumn color change, said last year was unusually warm through September and October. According to him, the weather this autumn was just as warm and it looked like the foliage was going to last late, but an early cold streak at the start of October sped up the process.
According to O’Keefe, this year’s foliage period started four to five days later than the average on record. He said one reason that the brilliance of the peak was reduced is that it was particularly windy last week. He said if it wasn’t for the stormy weather that blew many of the transforming leaves off the trees, the peak foliage period could have been a week or more later.
According to Kelty, the window of opportunity to enjoy the vibrant colors of foliage is closing because beginning in November, most leaves will have turned brown.
According to the MOTT, peak foliage area driving routes in the Pioneer Valley are Route 9 through Amherst and Hadley, Route 202 through Pelham and New Salem and Route 10 through Northfield. Routes in central Massachusetts include Route 9 along Brookfield, Route 148 along the Quabog River and Routes 32 and 32A through the towns of Hardwick, Petersham, Oakham and Barre.
