Maple Syrup: A Sweet or Sour Future?

Sugar maple buckets near Hubbard Lodge in Philipstown

Sugar maple buckets near Hubbard Lodge in Philipstown. (Photo by M. Turton)

Thankfully for maple-syrup lovers, global warming will not mean the demise of pancakes as we know them. At least not in the near future. 

But variations in the climate are creating challenges for producers of liquid gold. They’re being forced to adapt, particularly in the Northeast, where most American maple syrup is produced.

As with most crops, making maple syrup is all about the weather. Changeable, unpredictable, extreme weather is not good for syrup production, whether the temperature is too warm or too cold. 

Forty gallons of sap taken from a sugar maple boil down to produce a gallon of maple syrup. John Stowell, director of the Taconic Outdoor Education Center, says a 30-inch-diameter tree produces about 30 gallons of sap per season. 

In the past, the optimum conditions for collecting sap traditionally occurred from late winter to early spring, when nighttime temperatures are below freezing and daytime temperatures rose to about 40 degrees.

But that has changed. 

Pat Cronin, who owns Cronin’s Maple Farm in Hopewell Junction, taps about 4,500 sugar maples and produces up to 1,600 gallons of syrup each year. New York state as a whole produces 845,000 gallons annually.

“We used to tap from around the first week in February to about the first week in March,” said Cronin, who has produced syrup for nearly 20 years. This year, he began tapping in January. He said that in Vermont some producers started as early as December. 

Cronin said an early start usually signals an equally early finish, but that this season has been long and slow. 

“We had three or four 60-degree days in February that slowed things down,” he said. “We were still boiling sap on March 26.” 

Toni Lyn Morelli, a research ecologist with the U.S. Geological Survey who specializes in Northeast climate adaptation, noted that a recent study she contributed to, “Finding the Sweet Spot: Shifting Optimal Climate for Maple Syrup Production in North America,” concluded that by the end of the century the sugar maple tapping season will have shifted earlier by a month. 

The study also suggested we could see a 50 percent drop in syrup production in New England, excepting northern Maine, in the same time period, and that the region of maximum sap flow will shift north by 400 miles. That could spell the end of commercial maple syrup operations in the Highlands.  

The report also predicts large decreases in yields, a decrease in sugar content and an increase in poor production years in most syrup-producing areas. 

Even in Quebec, which produces more than 70 percent of the world’s maple syrup, only flat to moderate increases in yield are anticipated, the study found. 

“Maple syrup production isn’t going to go away in North America,” Morelli said. “But it is shifting.” 

Mark Isselhardt, a maple specialist at the University of Vermont’s Proctor Maple Research Center, said farmers will need to be “resilient, adaptable and good forest managers.” He said one adaptive strategy is to tap more red maples, one of four North American varieties of maple that can be used to produce syrup. Sugar maple sap has the highest sugar content. Black maple has good sugar content but a considerably smaller range and silver maple has the lowest sugar content. 

Red maples, however, can thrive under a wide variety of conditions, making the species more resilient to climate change. Its sugar content is slightly lower, but if vacuum tubing is used, red maples can produce higher volumes of sap than sugar maples. 

It takes about 50 gallons of red maple sap to produce a gallon of syrup equal in quality and taste to that produced from sugar maples, said Isselhardt. 

Farmers could also tap more trees, he said. “We know there is more sap to be harvested than is being taken.” He noted that only five to 10 percent of Vermont’s maples are tapped. 

But adding trees means more maintenance, making it more difficult for a farmer to keep close tabs on the system and achieve the highest yields, he said. “If they’re not able to get out there regularly to make repairs, it slows everything down,” he said.

Better leak detection, use of vacuum tubes and reverse osmosis (a process that eliminates water from the sap before it goes into the evaporator for boiling) can also maximize efficiency, Isselhardt said.

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