But geography doesn’t automatically prescribe vibrant colors — weather often plays a more important role. So where has the weather been conducive for good leaf peeping this year?
Perfect foliage conditions rely on a good combination of temperatures (not too hot and not too cold) and moisture (not too wet or too dry). The problem is that some areas have experienced these extreme conditions, particularly in the West and New England.
Over 75% of the West is under drought conditions. Over 80% of Massachusetts, Maine, Rhode Island and New Hampshire are experiencing severe drought.
But some of those same New England areas witnessing drought conditions also happen to be reporting more vivid fall colors.
“This year we are seeing exceptionally vibrant fall foliage in Vermont,” said Dr. William Keeton, a Forest Ecology and Forestry Professor at the University of Vermont. “It is due to a combination of factors, including good tree growth last year, mild drought and both warm days and cool nights over the last month. ”
While the drought may trigger more vibrant colors, the timing may be premature.
“The colors this year are coming about two weeks earlier than normal and will probably go by fast and furiously,” Keeton said. “Largely, this is because the drought creates stress for the trees — physiological stress. So from that standpoint, while the drought may enhance some of the colors, the stress is not a good thing and may be a harbinger of things to come with climate change.”
In addition to starting early, the duration of the leaf color is also likely impacted.
“In terms of fall foliage, drought can cause the leaves to change colors earlier, but they may also die and fall off earlier,” said Kaitlyn Weber, a data analyst for Climate Central. “Prolonged and more extreme drought can cause physical damage to trees such as root loss, slowed growth, and makes it harder for trees to protect themselves against pests and disease.”
Which is why the level of drought matters too.
Vermont, for example, is mostly in a moderate drought (level 1 out of 4), versus New Hampshire, Massachusetts and Maine, which are mostly in a severe drought (level 2 out of 4). And Rhode Island is almost entirely under an extreme drought (level 3 out of 4).
“A mild to moderate drought may actually enhance fall foliage to some degree, so long as it didn’t lead to a lot of ‘browning’ or early leaf drop,” Keeton said. “Then again, drought one year may mean less robust leaf production the next.”
So it isn’t always an instant impact. Often, the effects of droughts are delayed. Right now, 76% of Vermont is under moderate drought conditions or worse. But at this same time last year, 0% of the state was under drought conditions.
“Good tree growth last year allowed the trees to store up energy reserves and nutrients over the winter, resulting in robust leaf development this spring and summer,” Keeton said. “But this works the other way too…a bad drought one year can lead to poorer foliage the next.”
Extreme heat and climate change
Ideal conditions for vibrant foliage include warm days and cool nights. That encourages the production of a chemical called anthocyanin, which adds the red and purple…
Read More News: Fall foliage faltering under ‘Extreme Drought’ conditions