Predicting peak foliage in New Hampshire is anyone’s guess

  • Colorful leaves are seen last week from the Kancamagus highway near Lincoln.

  • Leaves begin to change on Kancamagus highway just west of Lincoln last week. GEOFF FORESTER—Monitor staff

  • Leaves begin to change as seen from the Kancamagus Highway just west of Lincoln last week. GEOFF FORESTER photos / Monitor staff

Monitor staff
Thursday, September 21, 2017

As has happened every fall since sometime after the glaciers left New Hampshire 12,000 years ago, about half of the 4.3 billion trees in the state are starting to lose their leaves in preparation for winter.

Happily for us, a subset of these leaves– most famously those on sugar maples, but also on many deciduous species in the state – change as the green chlorophyll that fueled trees all summer fades away, allowing the sugars and other chemicals in the leaf to show through.

Different species have different chemicals, and each creates a different color: Carotene is orange, xanthophyll is yellow, and anthocyanin is red. New Hampshire has roughly 70 deciduous tree species, a variety that creates a gloriously mottled mix, a blend of colors interspersed with the unchanging green of conifers that is unmatched in any other of the world’s leaf-peeping locations, such as Japan.

The question this time of year is: When and where will those colors be best?

The start of color change largely remains the same from year to year because it is triggered by the shrinking amount of daylight in fall. This triggers trees to shut down chlorophyll production and prepare for winter.

However, the length of time that leaves stay on trees for our viewing enjoyment depends on the weather during leaf-peeping season, while the range and brilliance of colors depends largely on weather during the summer, which affects the production of sugars in leaves.

Predicting the effect of either is difficult, however. Last year’s drought was expected to harm leaf-peeping, yet by most accounts the season was spectacular.

At least a half-dozen foliage trackers exist online, posted by news organizations like WMUR and Boston.com, business groups like visitwhitemountains.com, and the state’s tourism department at visitnh.gov.

Right now, colors are just starting to show on northern hillsides, although they have been visible for a week or more in wet and boggy areas, where tree species that turn sooner tend to congregate.

All the foliage trackers currently show estimates based on past years, with colors peaking in the North County next week, the White Mountains the week after, and in central New Hampshire during the traditional period around Columbus Day.

Anecdotal reports from the North Country indicate that this season is starting out with a bang, and tourism officials are predicting record crowds in the Lakes Region this autumn.

Note, however, that chasing specific locations in search of the elusive “peak foliage” can be frustrating. It’s best to head into areas where change has been reported and be flexible in your search.

(David Brooks can be reached at 369-3313 or dbrooks@cmonitor.com or on Twitter @GraniteGeek.)