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News - Changing Climate Could Affect State’s Maple Syrup Production

photoJenny Shrum wants to understand the relationship between climate and maple sap flow – and the potential effects on Maine’s maple syrup industry. It’s a big undertaking, one that could shed light on the future of one of Maine’s more distinctive brands.

The result has been a busy spring.

Shrum’s “laboratory” consists of a series of tapped trees outfitted with collection containers and digital cameras which transmit images remotely for close monitoring. And she’s begun talking to maple syrup producers big and small, hoping to better understand their motivations and how those factor into future forecasts.

Early deductions: Maine’s maple syrup industry may see some changes related to climate. Smaller producers would likely be the most affected.

Shrum, a Masters student at UMaine’s School of Biology and Ecology and a Graduate Research Assistant with the Sustainability Solutions Initiative, is studying how our changing weather patterns affect sap flow and the freeze-thaw cycle crucial to the process. Though Maine’s harsh winter delayed flow this year, the general trend has been toward warmer weather and earlier runs. Shrum is curious: if her sap flow research confirms that the maple trees will continue to flow ever-earlier in Maine, will the people who produce maple syrup also be willing to continue – even if that means cutting into the more lucrative timber season? Though larger syrup producers may be able to adjust, smaller landowners, in most cases, use their acreage and precious time for a variety of enterprises.

“Say that in general every year starts slightly earlier and cuts into the timber harvest season more and more. For some producers who tuck the sugaring season into a pocket where no other economic activity is occurring, this infringement on their primary income source could be a deal-breaker. That alone could greatly alter the kinds of producers that comprise the maple syrup community. Climate change might end up favoring those producers whose main economic activity is sugaring,” Shrum said.

Shrum is amassing data from maple stands in Orono, Albion and Dixmont. In addition to monitoring sap flow, she has installed weather stations that record weather data every hour and temperature loggers at various depths in the soil.  With these data, she will be able to relate the sap flow rate with weather and soil characteristics. Though the exact mechanisms of sap flow remain something of a mystery, Shrum says this much is known: sap flow depends on an intricate process that involves the freezing and thawing of the maple tree’s xylem tissue, the molecule sucrose which maple trees use to transport energy stored as carbohydrates between seasons, and water which trees keep in their tissue and absorb through their roots. Since temperature and precipitation are the two factors most likely to change in future decades, climate change could very well interrupt the delicate cycle of sap flow

“Producers and scientists both agree that earlier start dates are a reality, but that might not be the full picture. For instance, long-term forecasts predict that we’re going to be seeing a lot less snow pack in the winter. Snow acts like a thermal blanket, and without it the soil will be more susceptible to freezing, ,” Shrum said. “Maple tree tissue creates positive pressure during the normal freeze-thaw cycle, but it may need to soak up water from the soil to recharge this pressure. Maple trees have relatively shallow roots, and the soil at these depths might well be frozen in the future.” So, not only might the cycle be stunted, but there could be root damage as well, she said.

And how will this all affect Maine? It comes down to this: the maple syrup stands that charm tourists and the local syrup hauls that land in independent Maine markets could potentially see a slowdown.

That would be unfortunate on more than one level, Shrum says. Not only might smaller producers be stymied, Maine could see a reduction to one of its most sustainable practices.

“Tapping trees is sustainable on so many levels. Producers take less than ten percent of a tree’s total sap supply, so a healthy tree will continue to thrive. Producers often collect sap in forests as they naturally exist, so the ecosystem itself remains intact. And the beauty of harvesting sap versus fishing or timber is that what you take won’t impact your neighbor’s take or what you are able to collect the following year. It’s the immaculate harvest.”

Shrum will continue her research through the spring and hopes to construct some forecasts of her own by year’s end. These biological predictions combined with findings from her interviews with producers will hopefully provide a clearer vision of the future of maple syrup in Maine.

Supported by National Science Foundation award EPS-0904155 to Maine EPSCoR at the University of Maine.


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