On a cold, February day in the hills of the Finger Lakes, thousands of leafless maple trees stood dormant, waiting patiently for the kiss of spring. Armed with a hammer and drill, Aaron Wightman trudged through deep snow in the Arnot Teaching and Research Forest.

Wightman pointed the drill into the bark of a sturdy tree and followed with a high-pitched thrust forward. Then, he hammered a spout into the wooden hole. In a few weeks, the tree would give forth a thin, sweet sap that would become maple syrup.

Wightman’s family has made maple syrup for generations. He has been tapping trees since childhood, but he’s seen warming winter-spring temperatures push the tapping season back by more than a month.

“We didn’t even tap until the end of February or early in March when I was young,” said Dr. Wightman, the co-director of the Maple Program at Cornell University. “Now we tap in early January.”

Americans are the world’s leading consumers of maple syrup, and New York State holds the title of the second-largest U.S. supplier after Vermont. Now, in the midst of a global pandemic when more of us are cooking at home, demand for the gold stuff has gone through the roof.

But this swell in demand coincides with a changing climate that brings warmer winter temperatures to much of the Northeast. And winter and early-spring temperatures determine how well precious maple sap will flow. The climate problem was so detrimental last year that it squeezed the global supply of maple syrup.

Unabated, it could even threaten maple syrup production on this side of the northern border.

Aaron Wightman holds a check valve spout before hammering it into a sugar maple tree. The spout prevents microbes from entering the taphole. The sap-collection system includes 50 miles of tubing inside a 400-acre sugarbush at the Arnot Forest, February 24, 2022.

Aaron Wightman holds a check valve spout before hammering it into a sugar maple tree. The spout prevents microbes from entering the taphole. The sap-collection system includes 50 miles of tubing inside a 400-acre sugarbush at the Arnot Forest, February 24, 2022.

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Aaron Wightman holds a check valve spout before hammering it into a sugar maple tree. The spout prevents microbes from entering the taphole. The sap-collection system includes 50 miles of tubing inside a 400-acre sugarbush at the Arnot Forest, February 24, 2022.
Shantal Riley

That’s because the sugar maple — Acer saccharum — is exquisitely sensitive to changes in temperature. It’s a little like Goldilocks. The flow of sap depends on temperatures being "just right."

“When the trees undergo a period of freeze followed by thaw, that sugar-laden sap is pressurized inside the tree and we can drill a hole in the tree and the sap flows out,” Wightman said.

In the Northeast, these freeze-thaw events used to happen in early-to-mid spring, he said.

“Now we're finding that sap collection peaks more in the beginning of February through the end of March,” said Wightman. “We're having fewer of those freeze-thaw cycles.”

Wightman and his small crew operate a vacuum-tubing system that connects to about 8,000 maple trees. Once collected, the sap runs through a reverse-osmosis machine that removes 80% of the water — and sends the sweet concoction onto an evaporator, which concentrates it into a thick, tea-colored syrup.

Aaron Wightman turns on a reverse-osmosis machine that concentrates maple sap at the Arnot Teaching and Research Forest, just south of Ithaca, New York, February 24, 2022.

Aaron Wightman turns on a reverse-osmosis machine that concentrates maple sap at the Arnot Teaching and Research Forest, just south of Ithaca, New York, February 24, 2022.

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Aaron Wightman turns on a reverse-osmosis machine that concentrates maple sap at the Arnot Teaching and Research Forest, just south of Ithaca, New York, February 24, 2022.
Shantal Riley

The system draws sap through rain and snow. But it was no match for the spring 2021, when excessively-warm temperatures brought the season to an abrupt end. Tapholes dried up and New York’s maple syrup crop fell by 20%. Wightman thinks that figure could be even higher.

“It was a horrible year, by all measures,” he said.

After last year’s maple sugaring season was cut short by balmy weather, New York’s maple farmers are hoping for a break from the heat.

Sapping syrup reserves

Native Americans used maple trees for food and medicine centuries before the arrival of Europeans.

“Maple syrup is a true, niche, North American crop,” said Dr. Navindra Seeram, a natural product chemist at the University of Rhode Island. “This is one of the few crops which was not brought by the settlers, the Europeans, when they came to America and Canada.”

Hundreds of years later, climate change is having a direct effect on maple trees, and this includes warming summers.

“That's because the trees that we rely on to make maple syrup do most of their growth in the summertime,” said Dr. Pamela Templer, a biology professor and forest ecologist at Boston University. “If the conditions are right in summer -- it's not too hot, it's not too dry -- then the trees are going to have higher rates of photosynthesis.”

The more photosynthesis, the more sugar the trees can produce. But summer 2020 was especially hot and dry in the Northeast, which led to poor growing conditions and less sugar in sap the following spring.

Sugar maples prefer cool-moist climates, Templer notes. So much so, that models predict the range of sugar maples will shift north.

We're not going to have the right conditions to make any maple syrup whatsoever.

Pamela Templer, professor and forest ecologist, Boston University

“As air temperatures are warming, we're seeing a movement of the distribution of sugar maples northward,” she said. “Some people think that, by the year 2100, maple syrup production could shift about a month earlier, which means eventually it's going to happen so much earlier that we're not going to have the right conditions to make any maple syrup whatsoever.”

The lackluster 2021 season led to a supply shortfall that happened to overlap with a global rise in demand for maple syrup. According to the Québec Maple Syrup Producers, their global sales went up by 23% last year. Demand was so steep that Québec, the world’s leading supplier, had to dip into its strategic reserve of syrup.

Yes, French Canadians have a strategic reserve of maple syrup, located in Laurierville, Québec, about two hours northeast of Montréal. The reserve shelters the beloved golden syrup in 600-pound drums.

But the production shortfall siphoned 65% of the reserve last year, the group said. “Production went down, and consumption went up,” said David Hall, president of the group’s Montérégie East region. And on a sour note, the sap wasn’t very sweet, he said.

“The sugar content in the sap was lower, and I mean a lot lower,” Hall said. “We had plenty of sap. It just had no sugar in it.”

Rolling with the punches

Pure maple syrup — not to be confused with processed pancake or table syrup — is about 67% sugar when finished. It also contains a slew of nutrients.

“It's well known to have potassium, manganese, magnesium, calcium, as well as vitamins like B12, thiamine, along with phytonutrients — a wide diversity of natural compounds known to be present in other healthy plant foods such as green tea, red wine, berries and flax,” Seeram said. But, he added, pure maple syrup packs more than 50 calories per tablespoon.

“This is a product which you should drizzle and not guzzle,” Seeram said. “It should be used like any other sweetener, in moderation.”

Other species such as red and silver maples have ranges that extend further south. They can withstand warmer temperatures, but their sap is less sweet.

Olivia’s Sugar Shack is located at Happy Day Farm in Manalapan, New Jersey,

Olivia’s Sugar Shack is located at Happy Day Farm in Manalapan, New Jersey,

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Olivia’s Sugar Shack is located at Happy Day Farm in Manalapan, New Jersey,
Shantal Riley
Tim Stockel looks up at a maple tree, connected to a tubing system that collects maple sap at Happy Day Farm. Stockel’s trees are mostly red and silver maples, February 20, 2022.

Tim Stockel looks up at a maple tree, connected to a tubing system that collects maple sap at Happy Day Farm. Stockel’s trees are mostly red and silver maples, February 20, 2022.

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Tim Stockel looks up at a maple tree, connected to a tubing system that collects maple sap at Happy Day Farm. Stockel’s trees are mostly red and silver maples, February 20, 2022.
Shantal Riley

At the Happy Day Farm in Manalapan, New Jersey, farmer Tim Stockel heaved logs into the bottom of a wood-fired evaporator in late February. The machine takes about 80 gallons of sap, made mostly from red maples, to make one gallon of maple syrup.

“Here in New Jersey, we don't have as many sugar maples, at least not here in Monmouth County, central New Jersey, where I am,” said Stockel. “So, I have to work a lot harder boiling that sap water down to end up with maple syrup.”

While his maple trees were productive last year, his other crops didn’t do as well.

“We got hit with two horrendous storms,” he said. “My zinnia flowers and blueberry plants were in one foot of water. So yeah, storms that do come through, they are rougher and they are stronger.”

When asked how he was coping with the extreme weather, Stockel said he’s resigned to face whatever might lay ahead. “(I’m) just rolling with the punches, you know,” Stockel said.

​​Tim Stockel stands next to a 550-gallon holding tank, attached to a tubing system that collects sap water from hundreds of red and silver maples on Happy Day Farm in Monmouth County, New Jersey, February 20, 2022.

​​Tim Stockel stands next to a 550-gallon holding tank, attached to a tubing system that collects sap water from hundreds of red and silver maples on Happy Day Farm in Monmouth County, New Jersey, February 20, 2022.

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​​Tim Stockel stands next to a 550-gallon holding tank, attached to a tubing system that collects sap water from hundreds of red and silver maples on Happy Day Farm in Monmouth County, New Jersey, February 20, 2022.
Shantal Riley
Farmer Tim Stockel inspects the finishing pan inside an evaporator at his sugarhouse in Manalapan, New Jersey, February 20, 2022.

Farmer Tim Stockel inspects the finishing pan inside an evaporator at his sugarhouse in Manalapan, New Jersey, February 20, 2022.

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Farmer Tim Stockel inspects the finishing pan inside an evaporator at his sugarhouse in Manalapan, New Jersey, February 20, 2022.
Shantal Riley

Extreme weather events — ice storms, flooding and tree-damaging winds — are another aspect of climate change with which maple farmers must contend.

The melting snowpack is another issue, as it exposes the ground to freezing temperatures that can damage sensitive root systems, said Eric Randall, former president of the New York State Maple Producers Association. “That snowpack acts as a giant refrigerator,” he said.

Randall is also concerned about threats posed by invasive species like the spotted lantern fly and the Asian longhorned beetle, which together have decimated thousands of maple trees in New York, Massachusetts and other states.

But he remains positive about the future of American-made maple syrup.

“It's as pure a product as you can get it,” Randall said, pointing to growing demand for products like maple soda and beverages. “It's not just a pancake topping anymore.”