However, geography doesn’t automatically define vibrant colors. Weather often plays a more important role. So, where is the good weather to see good leaves this year?
Perfect leaf condition depends on a good combination of temperature (not too hot or too cold) and moisture (not too humid or too dry). The problem is that some areas have We have experienced these extremes, especially in the West and New England.
More than 75% of the west is drought. More than 80% of Massachusetts, Maine, Rhode Island and New Hampshire suffer from severe drought.
However, some of the New England regions that have witnessed drought conditions report sharper fall colors.
“This year we are seeing very vivid foliage in Vermont,” said Dr William Keaton, professor of forest ecology and forestry at the University of Vermont. “It’s because of a combination of factors that include last year’s good tree growth, mild drought, and both warm and cool nights over the past month.”
While drought can cause more vibrant colors, timing can be premature.
“This year’s color will come out about two weeks earlier than normal, and it will probably go fast and furious,” Keeton said. “Unfortunately this is because drought creates stress (physiological stress) on the tree. So, from that point of view, drought can improve some color, but stress is not a good thing and could be a harbinger of what comes with climate change.”
In addition to starting early, the period of leaf color can also be affected.
Climate Central data analyst Kaitlyn Weber said, “In foliage, drought can cause the leaves to change color earlier, but the leaves may die and fall earlier.” “Persistent, extreme drought can cause physical damage to trees such as root loss, slow growth, and makes it more difficult for trees to protect themselves from pests and diseases.”
That’s why drought levels are also important.
For example, Vermont is mostly in moderate drought (level 1/4), while New Hampshire, Massachusetts, and Maine are mostly in severe drought (level 2/4). And Rhode Island is almost entirely suffering from extreme drought (stage 3 of 4).
“A mild to moderate drought can actually improve fall foliage to some extent, as long as it doesn’t cause a lot of’browning’ or premature foliage,” says Keeton. “Then a year of drought could mean that the next time leaf production declines.”
So it is not always an immediate effect. Often the effects of drought are delayed. Currently, 76% of Vermont has moderate drought conditions or higher. But at the same time last year, 0% of the state was in drought.
“Last year good tree growth has allowed the tree to store energy and nutrients during the winter, and as a result, robust leaves have been developed this spring and summer,” said Keeton. “But it works the other way too. A severe drought during the year can cause the foliage to deteriorate the following year.”
Extreme heat and climate change
Ideal conditions for vibrant foliage include warm days and cool nights. It promotes the production of a chemical called anthocyanins, which add red and purple to some species, such as maple.
“The contrasting temperature between night and day accelerates the loss of chlorophyll in the leaves, leaving us with a secondary photosynthetic pigment (carotenoid) that gives us a yellow and orange hue,” Keeton said.
However, like drought, severe heat can stress trees, causing premature browning or loss of leaves. And when autumn feels like an extension of summer, moderate heat or prolonged heat can delay the transition to fall color because the tree does not receive a signal that autumn has come.
“Plants can completely miss the signal and lose leaves faster,” Weber said.
In western states such as Colorado and New Mexico, tourism is often energized by travelers looking for vivid aspen leaves and rubbing oak trees. Together with Nevada and Utah, both states had the hottest August this year. New Mexico had the second dryest summer on record (June to August).
“The causes of the foliage are complex and are not really fully understood,” Keeton said. “The drought is just one of a few factors, the other is the contrast between day and night temperatures in the photovoltaic period and autumn. All this shows how fascinating our forest ecosystem is!”
Wildfires add another hurdle/dilemma
Wildfires will also complicate leaf peeking in Colorado and California this year. Some states still deal with poor air quality and overcast skies due to smoke. That haze blocks your ability to see vivid colors.
Not all areas are expected to be bad. Most of the southeast and midwest regions have very good weather this year, so foliage will flourish this season.