Maple Syrup Threatened by Climate Change

Share Button

By Britnae Purdy

Ojibwa woman gathers maple syrup

Enjoy your morning pancakes with maple syrup? Thank the Native Americans. Legend holds that Woksis, an Iroquois chief, had a habit of slashing his knife into a tree each night after a day of hunting. One warm morning he pulled his knife from the tree and was surprised to find sap dripping out. His wife, not wanting to make a trip to the stream, collected the watery sap in a pail to cook dinner with later that night. The meat came out sweet and delicious, and Woksis began collecting maple sap every night for his meals.

Regardless of how sap was actually discovered, it is a fact that the Native Americans of New England and Canada had been collecting maple sap and processing it into syrup long before colonization. After collecting the sap in hollowed-out logs, they would insert white-hot field stones to bring the sap to a boil. They would either cool the sap at this point to make syrup, or continue to process it until the sap crystallized into maple sugar, which would not spoil and could be easily used to flavor dishes or as a quick source of energy.

When European settlers arrived, the Iroquois traded maple sugar with them and eventually taught them the sugaring process. The settlers added their own techniques to the process, and sap collection quickly became  standard practice for households across New England and Canada.

Unfortunately, this Native tradition, and maple syrup for your pancakes, may become extinct due to climate change. Atypically warm weather is disrupting the trees natural process for making sap. Maple trees produce the best sap on cool days preceded by freezing nights – the cold weather causes the sap in the tree to freeze, creating a low-pressure vacuum that draws more sap up from the roots. When temperatures rise the next day, the sap melts and oozes through the tree, making for easy collection.

When temperatures stay abnormally warm, as they have been lately, this process does not occur. Additionally, the warm weather causes the trees to begin to bud. The hormones that trigger budding also decrease the sap’s sugar content and spoil its taste. This means that it takes much larger quantities of sap to boil down to a gallon of syrup. Furthermore, warmer weather caused by climate change allows pests to prosper, killing young maple trees before they are able to reach maturity – trees must be 40-50 years old to produce the best quality of sap. Acid rain has also become a constant stressor on the trees.

Tappers who invest in expensive, modern vacuum systems are still collecting a decent amount of sap from their trees, but hobbyists, artisanal tappers, and communities who adhere to the traditional practices are suffering. The tapping season, which typically spans a month, is shortening to one or two weeks, and tappers are being forced to begin the process earlier and earlier in the year.

The trees are also fed up with climate change. In a phenomenon known as tree migration, maple trees are moving further north and up mountain slopes– a study by UVM ecologist Brian Beckage found that tree species in Vermont have shifted 90 meters since 1964, seeking colder climates. Maine, Wisconsin, Vermont, and New York, which combined produce 80 percent of the United States’ maple syrup, will lose production to Canada. Quebec currently taps one-third of their trees and produces 5.35 million barrels a year, 70 percent of the global supply.

Climate change experts predict that the maple sugaring industry could be wiped out by 2100, destroying a $65 million business and taking with it centuries of agricultural practices rooted in traditional indigenous knowledge.

Are you Indigenous or interested in Indigenous issues? Join us for Proud To Be Indigenous Week in May. Learn more at:

(Photo: Ojibwa woman gathers maple sap circa late 1800s to make maple syrup and sugar. From Minnesota Landscape Arboretum,