As the days grow shorter and New Hampshire delves deeper into fall, a number of sensory experiences accompany the changing weather. The air becomes crisper and clearer. Chrysanthemums of all colors accost front porches, and plump, orange pumpkins decorate doorsteps. But what would a New Hampshire autumn be without its brilliant foliage? The changing leaves define the season in the Granite State, and the vibrant colors mean big bucks for New Hampshire, as “leaf peepers” flock to the area.

The New Hampshire Division of Travel and Tourism launched a new Web site (www.visitNH.gov) in June, which highlights where to go and what to do during foliage season. It features an interactive map, calendar, text messaging, podcasts and video clips of autumn hot spots. Technology is finally catching up with the ancient art of leaf peeping.

“We’ve been trying to reach more visitors, and doing the interactive media is a great way to do it and give people the most up-to-date information out there,” said Lori Harnois, spokesperson for the NHDTT. “We were the first New England state to do text messages, and our capabilities with the video clips provide people with a good visual to entice them to visit New Hampshire. The podcasts provide three tours in the state to let people know what they can do. We also have an 800 number that people can call,” she said.

Text message alerts have been used in the past to update snow conditions for skiers and wave conditions for surfers, but the foliage alerts are new. A text message sent on Oct. 4 read, “VisitNH Foliage Alert: Rt. 16 to 13-mile woods; 26 to Dixville Notch; Rt. 302 to Crawford Notch; Kancamangus Hwy (112); Rt. 11 Lake Winne; 1-800-258-3608/details.”

Leaf peeping starts around mid-September and usually runs until mid-November, according to Harnois.

“We’re expecting more people coming to New Hampshire this fall,” she said. “The weather is in our favor this year, and gas prices are lower this year. On the international side, with the current exchange rate, New Hampshire is a really great deal. We get a lot of visitors from the UK, Germany, France, Ireland and Japan.” 

Mark J. Okrant is a tourism development researcher at the Institute for New Hampshire Studies at Plymouth State University. He predicts that somewhere in the vicinity of 7.5 million visitors will come to New Hampshire this fall. With a population of only 1.3 million, that’s more than six times the number of people that reside in the state.

“The fall season is very important to New Hampshire,” Okrant said. “It generally ranks second in terms of numbers visiting the area. We have an increase of 1 to 2 percent each year. It’s been gradual, but also very steady.” Okrant expected more than 600,000 tourists to visit New Hampshire on Columbus Day Weekend alone. 

As cars stream into New Hampshire and snake their way up north, their slow moving vehicles choke the roads. Exhaust from tailpipes fills the air, emitting a distinctly Massachusetts odor. Fortunately, along with the bad driving and annoying questions, tourists bring massive amounts of money into the state. Okrant predicts that visitors will spend around $1.1 billion in New Hampshire during the fall season. Over Columbus Day weekend, visitors were expected to spend $97 million.

More Canadians are expected to visit New Hampshire this fall too, according to Okrant.

“The number one factor in terms of influencing visitors from Canada would be the exchange rate.” The Canadian dollar is now stronger than good old American greenbacks, and Canadians are expected to head south to take advantage.

Higher tolls on interstates 95 and 93, as well as Route 16, will ensure that the government gets a portion of the tourism proceeds, but the biggest beneficiaries tend to be private businesses.

“Sleeping and food services both receive a considerable amount of money. One thing that a lot of people don’t realize is that retail establishments also benefit. There is quite a bit of shopping,” Okrant said. “Another interesting area that a lot of people don’t immediately think of is farms and farm stands. Agricultural tourism as a whole is on the rise.”

So, what produces this lucrative natural phenomenon? Chlorophyll is the chemical that makes leaves green. Leaves also contain other colors that are outshined by the chlorophyll for much of the year. But, as autumn approaches, the shorter days and cooler nights cause chlorophyll to break down, and nutrients in the leaves move to the trees for winter storage. As a result, bright reds, yellows and oranges begin to appear. The autumn colors depend on which pigment is the most plentiful in each tree. It’s a scientific process that creates an aesthetic masterpiece.

Jerry Monkman is a professional photographer, writer and co-owner of the Portsmouth business EcoPhotography (www.ecophotography.com). He and his wife, Marcy, specialize in adventure, travel and nature photography. Most of their work focuses on New Hampshire, Maine and other New England states. In 2003, Monkman and his wife published a book called “The Colors of Fall: A Celebration of New England’s Foliage Season,” which is available at Portsmouth Public Library. Monkman is professionally attuned to the aesthetic qualities of autumn. 

Asked what draws people to New Hampshire in the fall, Monkman had a singular answer.

“I think it’s the color,” he said, “this intense, saturated, Technicolor world. It’s such an iconic part of what makes New England special.” Having grown up in Illinois, Monkman did not experience the wonders of fall in New England until he moved east. “When we came out here and first experienced the fall, we were really in awe of the beauty of the season,” he said.

Capturing a fall foliage image requires breaking down a scene so that it’s simple enough to translate into a two-dimensional photograph, but still powerful enough to interest the viewer, according to Monkman. Many of his images tell a story. “I try to create a sense of what the season really is. I try to play off those ideas of change and the dying off of summer, going from incredible beauty to the starkness that is to follow,” he said. “We try to capture how fall really is a time of change. But, sometimes, I take a picture that just looks really cool.” As for favorite fall forests, Monkman prefers “any good northern hardwood forest, but the White Mountains and Acadia both have incredible beauty.”

Atmospheric circumstances can lead to off years for foliage. A combination of temperature, rainfall, frost and other uncontrollable factors dictate how “good” the foliage is on a given year. But, according to Okrant, the biggest problems arise when people in the media predict it will be a bad year for foliage.

“Perception becomes the greater part of reality. The fact of the matter is, if some so-called expert comes on the news and says this year will be bad, people won’t come. Tour groups will cancel,” he said. “It has happened in the past. But all signs from what I’m hearing is it will be very good this year.”

Some threats to autumn foliage have sprung up in recent years. Take a stroll down to South Mill Pond in Portsmouth. There, you’ll find a number of maple trees standing like sentries along the waterfront. Take a closer look at the leaves hanging on the branches, and you’ll notice that they are blemished with a disease commonly referred to as “leaf blight.” Although it sounds like a medieval infection, the disease is really just a combination of different fungi, known as anthracnose. Each species of fungus in the anthracnose genus creates black and brown blotches that look like oversized zits or moles.

Think of anthracnose as athlete’s foot for a tree. The same conditions that are conducive to the foot fungus—moisture, temperature and humidity—are also conducive to a tree fungus. Each fall, leaves infected with anthracnose fall to the ground. If those leaves aren’t properly disposed of, the anthracnose spores remain intact until the following spring. When conditions are right, the spores are released and picked up by spring breezes. They are carried through the air until they settle on another tree.

Once attached to a leaf, the fungus begins to kill leaf tissue, creating the black and brown blotches noticeable on maple, sycamore, ash, oak, hickory, birch, linden and dogwood trees. Last year, New Hampshire experienced a profusion of anthracnose, but levels are low this year. If specific trees are hit hard several years in a row, there is a good possibility that twigs, branches and, eventually, whole trees will be affected.

“It’s usually not a threat to the health of the tree. In general, a lot of the diseases wouldn’t affect fall foliage colors,” said Cheryl Smith, extension professor and plant health specialist with the University of New Hampshire Cooperative Extension.  

On the Seacoast and surrounding parts of the state, warm weather this fall has pushed the peak season back.

“It seems like the foliage is later than it usually is, but New Hampshire forests have always been resilient and brilliant,” said Don Black, Strafford County forester with the UNH Cooperative Extension. “We’ve had really good weather, and I think the extended warm weather has made it easier for leaves to stay on longer,” he added.

Many people fear that global warming will cause temperatures to rise and continue to push peak season later into the fall. Perhaps this will have long-term effects on foliage tourism. But, for now, leaf peeping business is booming.