Once winter nights dip below freezing and the days warm up above freezing sap begins to flow in sugar maples marking the start of the syrup season. U.S. maple syrup production is a global industry, which has been increasing by nearly 10 percent per year over the past decade according to the USDA’s National Agricultural Statistics Service 2017. With climate change, daily temperatures are on the rise, which affects sap flow and sugar content. By 2100, the maple syrup season in eastern North America may be one month earlier than it was during 1950 and 2017, according to a study published in Forest Ecology and Management.
The study examined six sugar maple stands from Virginia to Québec, Canada, over a six-year period. The sugar maple stands are located in: Divide Ridge in southwest Virginia; Southernmost Maple in central Virginia; Indiana Dunes National Lakeshore in Indiana; Harvard Forest in Massachusetts; Dartmouth Organic Farm in Hanover, New Hampshire; and Chicoutimi in Québec, Canada.
Maple syrup production is impacted by two climate sensitive factors: sugar content, which is determined by the previous year’s carbohydrate stores and sap flow, which depends on the freeze/thaw cycle. As a sugar maple tree thaws, the frozen sap begins to move through the tree.
The research team sought to test how monthly and season-long average temperatures during the tapping season, and temperature and precipitation from the preceding year, affect sap flow.
Read more at Dartmouth College
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