Maple Syrup and Climate Change

Continuing with my recent focus on global warming and in light of the fact that it is prime maple sugar season (as evidenced by a recent Boston.com travel special), it is time to delve a little deeper into how climate change could impact this New England tradition.

With warmer temperatures and more erratic weather, the ideal maple syrup harvesting climate is slowly shifting northward into Canada according to a Christian Science Monitor article.

The story sights a rather striking statistic: in the 1950’s 80 percent of the world’s maple syrup production came from the United States with the remaining 20 percent coming from Canada. But, by 2005 (when the story was published), those percentages were reversed.

So, what caused this spike? As this story explains (and I have learned first hand through research for another course I am taking at Northeastern this semester – the Environment in 2090), if a projected 6 to 10 degree Fahrenheit rise in temperature by the end of the century holds true, maple trees will have slowly migrated north, leaving oak and hickory trees as the predominant species.

The maples simply will not be able to adapt to different levels of pests, air pollution and other stress factors caused by the warmer temperatures. Meanwhile, oak and hickory trees will be much less affected, leading to their predominance.

Of course it is not only the disappearance of maples that is hurting syrup production. When the temperature drops below freezing, the sap is pulled out of the tree branches and into its roots. Then, when the mercury rises above 32 degrees Fahrenheit, that sap is expelled through the tree’s wounds (such as a hole dug by a syrup harvester).

So, with less dips below freezing, there are less opportunities to for the syrup to be expelled and, therefore, a worse season. For an alternative explanation of this, take a look at the Christian Science Monitor story. Although it is a few years old, it does a great job explaining the phenomena. And, for a graphic representation, check out Boston.com’s feature linked to in the first paragraph of this post. It also has discussion forums and a map of maple sugar farms throughout New England.