In this March 4, 2011 photo, Peter Purinton puts a check valve tap into a maple tree in Huntington, Vt. The device was developed by maple researchers at the University of Vermont as a means of extending the six-week sugaring season. (AP Photo/Toby Talbot)
In this March 4, 2011 photo, a Check Valve Adapter is seen with a bottle of maple syrup in East Montpelier, Vt. The device was developed by maple researchers at the University of Vermont as a means of extending the six-week sugaring season. (AP Photo/Toby Talbot)
Last year, when the sap stopped running from some of Bruce Curavoo’s maple trees, it kept running in others. He got enough to make about 300 more gallons of syrup from his crop.
His secret: A tiny adaptor that, when plugged into tap holes, helps reduce the amount of sap flowing back into trees from the vacuum tubing used to carry it to sugarhouses for boiling into maple syrup.
“They work,” says Curavoo, 36, of Starksboro, who used the device on half his 5,000 trees last year and will use it on all of them this year. “The longer you keep the sap running, the more [syrup] you make.”
Last year, he used the check valve adaptors on half of his trees. This year, he’s got them on almost all the trees as he awaits the start of the season, which typically begins in mid-March.
The adaptors were developed by maple researchers at the University of Vermont to extend the six-week sugaring season. By reducing backflow, the gadget limits the amount of naturally-occurring pseudomonas bacteria, microorganisms that can end sap flow if they get back into the tree, causing it to reflexively wall off the tap hole.
Made of hard nylon, it’s about an inch tall, sells for 35 cents per unit retail and looks like a rocket ship. Developers say it has big possibilities — the potential to sharply boost sap yield.
Typically, when a vacuum system is shut off or a line is punctured or ripped out by a falling tree, the tapped tree begins to suck sap back in from tubing, sometimes carrying bacteria. If the tree detects that, it walls off the tap hole, stopping sap production.
Last year, maple production nationally dropped by nearly 20 percent, according to the U.S. Department of Agriculture, the result of warm weather that started sap runs early — before some trees were tapped — and ended them in early April.
Vermont, the nation’s leading producer, made 890,000 gallons of maple syrup, down slightly from the year before because of a string of early April days with temperatures in the 70s and 80s.
Sugar makers in Maine, New Hampshire, and New York tried the device for the first time in 2010, though no one knows exactly how many, or how they affected production overall.
It takes about 40 gallons of sap to make a gallon of maple syrup, and the sap starts running from trees when temperatures rise into the 40s by day and drop back into the 20s by night.
“The ones that have used them are using them again, they feel there’s promise in them,” said Peter Purinton, a maple-sugar producer who used the devices on his trees last year and distributes them for supplier Leader Evaporator Co.