Sugarmakers (as those who make maple syrup are known) have, for centuries, had to contend with whatever Mother Nature throws at them come late winter and early spring.
The maple season is short and entirely subject to weather conditions. The traditional maple sugaring season extends from early February until late March, depending greatly on the weather, according to the Maple Syrup Producers Association of Connecticut.
Why is that? Night temperatures that fall below freezing and warm, sunny days are necessary to make sap flow in the maple trees. Once trunks are tapped, the season (hopefully) lasts for about six to eight weeks – until the nightly freeze no longer happens and the sap stops flowing (or the trees start to form buds).
So what happens when winters are a little bit warmer than usual? Some regions along the southern edge of the sugar maple’s natural habitat are already starting to see a decline in production. Maple sap seasons which have generally remained the same for decades are now beginning earlier too.
ACERnet (the Acer Climate and Socio-Ecological Research Network – Acer being the genus of maple trees) has a research team monitoring sap flow at sites across the sugar maples’ range, from Virginia to Quebec, to understand how climate effects sap flow, sugar content and chemical composition.
ACERnet scientists have identified how changes in weather conditions impact sugar maple trees and sap production: there are fewer trees, reduced tree health and growth, shortened tapping seasons and decreased sap quality and quantity.
According to Maple from Canada, “One study found that, by 2100, the sugaring season may begin one month earlier than it did between 1950 and 2017. Another study found that warmer temperatures reduce the sugar content of maple sap, meaning it takes more to produce pure maple syrup.” Neither of those are bits of good news.
(That first study notes that the timing of sap collection advanced by 4.3 days for every 1º C increase in March average temperature, and that sap sugar content declined by 0.1º Brix for every 1º C increase in previous May – October average temperature.)
Additionally, maple syrup is classified into four grades, each having a distinct color and flavor. The different grades are harvested at different points of the season, so as the climate changes, the yields of each grade may also become more unpredictable.
Advances in technology can help, luckily. Vacuum pumps, which lower the pressure inside maple trees, speed up the flow of sap so more of it can be collected.
Varieties other than sugar maple are being looked at too. While the sugar maple tree is usually considered the best for producing maple syrup, other species of maple can also be used for this purpose (per Maple from Canada). These include the black maple and the red maple.
“Maple forests themselves play an important role in curbing climate change by capturing carbon and removing it from the atmosphere,” Maple from Canada reports. “By protecting natural carbon sinks like these and investing in renewable energy, the future of the maple syrup industry – and the world – can be secured.”
