Is there a correlation between amount of rainfall and amount of maple syrup produced?
Answers
Some farmers in the United States and Canada have noticed that the quantity and quality of their maple syrup is changing with climate variability, said Selena Ahmed from MSU's Department of Health and Human Development in the College of Education, Health and Human Development. Ahmed is co-leading a team of researchers who are investigating these observations.
According to Ahmed, some producers say they are seeing less light-colored syrups historically classified as "fancy grade" and more dark and amber syrups during warm years. At the same time, producers are beginning to tap their maple trees earlier in the year because of sap flow triggered by winter thaw, but also experiencing an earlier end to the maple tapping season with a warming spring. Cold nights and warm days trigger sap flow, and too much warmth brings an end to the season with budding maple trees that make for more unpalatable maple syrup. As a result, Ahmed said, some producers fear that they will ultimately lose money because lighter syrups -- that were once considered the highest grades -- used to be in the most demand with the best prices. With shifts in composition, the amount of sap required to make maple syrup is also shifting. Maple syrup is an industry worth millions of dollars, Ahmed noted.
Sap's sugar content determines the quantity of syrup that can be produced from a given amount of sap, Ahmed said, while secondary metabolite defense compounds contribute to the flavor, nutritional profile and health attributes of the syrup. Secondary metabolite compounds are recognized to play a defense role in plants and increase with environmental stress including increased pests and more extreme weather. However, she said the relationship of these factors to environmental variability is poorly known.
To learn more about the relationship between sap quality and environmental factors, Ahmed is co-leading an interdisciplinary, multi-year study as part of the international consortium ACERNet that has taken her and her collaborators across the range of maple forests and sugar bushes of North America from near the southern range of maple in Virginia to its northern range in Quebec, and from the eastern range of maple in New England to near its western range in Indiana. ACERNet collaborators include Ryan Huish from The University of Virginia's College at Wise; David Lutz from Dartmouth College; Joshua Rapp and Kristina Stinson from the University of Massachusetts Amherst; Toni Lynn Morelli from the Department of Interior Northeast Climate Science Center; and Boris Dufour from the University of Quebec in Chicoutimi.
The ACERNet team closely works with undergraduate students on maple sample collections from the start of the sap flow until its end, generally from February through April.