By JOSHUA A. KRISCH JAN. 5, 2015
The New York Times
Pancake lovers, take heart. In the coming weeks, maple farmers throughout Quebec, Vermont and elsewhere in the syrup belt will dust off their metal spiles for another harvest season, and some scientists are predicting that the sugary sap will flow even more freely than usual.
That’s because this year, the region is likely to have what is known in botany as a mast year — a time every few years when perennial trees like sugar maples synchronize their seed cycles, and flower as one. Low-seed years usually lead to mass blooms, and may bode particularly well for the maple syrup industry.
In a paper published recently in the journal Forest Ecology and Management, ecologists at Tufts University near Boston suggest that syrup and seed production are linked. Because 2014 was a low seed year for maples, the scientists reason, maple trees invested spare energy into producing more carbohydrates. This year, the trees will use those carbs to flower — and fill sugar makers’ pails with rich, sweet sap.
“When you collect sap to make syrup, what you are actually collecting is the stored carbohydrates of the tree,” said Joshua M. Rapp, a biologist at Tufts and an author of the study. “If those energy stores are affected by seed production, we should see a link between seed production and maple syrup production.”
That seed cycles affect syrup yield may come as a surprise to longtime maple farmers. Sugar makers historically relied solely on the weather to predict good and bad syrup years. Mast years, seeds and flowers seldom entered the picture.
“It’s like every good farming story,” said Matt Gordon, the executive director of the Vermont Maple Sugar Makers Association. “Some old-timer who paid attention to everything probably knew about it. But as a general rule, it’s not something that was widely paid attention to.”
Weather does, in fact, play an important role. The Vermont sugar makers and Tufts biologists agree that when it’s very cold in February or very warm in April, less sap flows from the trees. Naturally, that translates into a decrease in the syrup yield.
But when the researchers examined annual syrup production, they realized that weather data alone could not consistently explain wide fluctuations in yields from year to year. They suspected that the variation might have something to do with the concentration of sugar in the sap.
“For a long time, maple producers have known that weather affects how much you get,” said Elizabeth Crone, a biologist at Tufts and an author of the study. “We knew how to predict sap flow, but how do we predict how much sugar there will be in the sap?” Dr. Rapp and Dr. Crone found that they could consistently predict annual sap sugar concentrations by looking at seed counts from the previous year. A hypothesis formed: Every year, trees either invest in producing seeds and flowers, or dump their energy reserves into making extra-sugary sap.
Last year, maples enriched their sap reserves. Come harvest time, there should be more sugar in their sap, which will mean more fresh syrup to drizzle onto those pancakes.
Dr. Crone says he hopes that more accurate sap sugar predictions will help farmers plan ahead and set aside funds for leaner years. “For a local farmer, let’s say your income is fairly marginal and you want to budget your year,” she said. “This will tell them how much they can count on receiving that money.”
But Mr. Gordon says he suspects that the study will do little to change the steadfast habits of the average Vermont sugar maker. “It’ll be one of many things people pay attention to,” he said. “But I don’t know if it will seriously drive anybody’s decision making.”
Because data on sap sugar concentrations has not been collected in a systematic way, Dr. Rapp and Dr. Crone based their estimates on annual data for total syrup production — a somewhat unreliable figure.
The researchers’ hypothesis has merit, said Michael Farrell, the director of Cornell University’s sugar maple research and extension field station in Lake Placid, N.Y., though the data source is not ideal. Syrup production data “vastly underestimates the actual production, and nobody knows by how much,” he said.
Dr. Rapp and Dr. Crone acknowledge that more research is necessary, but they hope their study will encourage researchers and sugar makers to focus on the connection between seed cycles and syrup.
“Many people know about sugar maples, fall colors and maple syrup,” Dr. Crone said. “But until now, not a lot of people have paid attention to seeds.”