Photo by Bill Greene/The Boston Globe via Getty Images

Could climate change eventually wipe out sugar maple trees?

Jessica Brown
January 30, 2018

Maple syrup hasn’t been having an easy time lately. Last year the internet flooded with fears of a shortage of the sweet stuff, thanks to warmer weather. And you might want to hold the pancakes, because it could get worse.

Despite maple tapping being almost as old as breakfast itself, last year’s troubles are indicative of a bigger problem, according to a University of Michigan study. They zoomed in on Michigan, which is the fifth biggest maple syrup producer in the US, producing around 90,000 gallons of it every year, which equates to $4 million worth.

Following last year’s shortage, researchers have now predicted that the numbers of sugar maple trees in Michigan will continue to fall, and in a few hundred years they might be completely wiped out thanks to a drier forecasted climate with more risk of extended droughts.

Producers need warm days and nights below freezing to drive sap down the tree and stop it from budding, and last year’s sap-collecting season (usually between February and April) was unusually warm.

The new study settles previously inconclusive research on whether climate change is helping or hindering sugar maples. On the one hand, nitrogen compounds from cars, power plants, factories, and agriculture help boost growth of sugar maples by providing a fertilizing effect, and forests are being exposed to unprecedented levels of nitrogen. But this only helps “a bit,” according to the researchers, and its fertilizing effects will be outweighed by an increasingly dry climate, which might cause the species to disappear from the Michigan’s Lower State Peninsula altogether.

Researchers used data from four studies carried out across the state’s west-central Lower Peninsula to the north-western Upper Peninsula, which looked at the effects of climate change on forest growth and the ecosystem, done over 20 years and involving more than 1,000 trees. They concluded that climate change could lead to decreased growth and, in extreme cases, increased risk of death.

“Water demand may increase and soil water may become a limiting resource as the earth’s climate continues to change into the future,” the paper states.

The researchers concluded that if we see slight changes brought on by climate change, including a temperate rise of 1.3 degrees and a 14 percent increase in summer rainfall, sugar maple growth would be “slightly harmed.” If climate change is more extreme, and we see a temperature rise of 10 degrees and a 40 percent increase in rain by 2100, there will be a big decrease in sugar maple growth.

Photo by Joanne Rathe/The Boston Globe via Getty Images

Lead researcher on the study and professor at the University of Michigan, Ines Ibanez, says a decline in sugar maples is “pretty definite, given the forecasted climatic trends” and that mature trees will slow down their growth and seed production.

These effects could start to happen in a matter of decades, she says. “Adult trees are very resilient and live for several hundreds of years. It will be more noticeable in the seed production and recruitment of new individuals.”

Unless, that is, something major happens. “We might see rapid changes if disturbance events take place,” she says, “Like windthrow, heat waves, major droughts, or pest outbreaks. Adult trees could die and not be replaced in numbers large enough to maintain their current abundance.”

This could, she says, affect the supply of the beloved morning condiment. The period of time where conditions are ideal for the production of maple syrup has already been reduced over recent decades.

And climate change won’t just affect the production of maple syrup, but its quality and sugar content, too. Barry Rock, a forest scientist and Professor of Natural Resources at the University of New Hampshire, told National Geographic that the sugar in maple’s sap is half what it was 50 years ago, making the taste less sweet, and it’s because of rising temperatures.

Suppliers on the ground are already seeing changes. Amber Munday, from Harwood Gold, a family business running since the late 1800s, says climate change is a “major concern” for her business.

“The biggest change we have seen are the weather pattern shifts. We are tapping trees and making maple syrup much earlier than we have in the past; on average, 30 days earlier. The quantity of our supply has not changed much, but as our winter grows shorter this will become a bigger concern for future production,” she says.

“At this time, we are still problem solving how we will deal with future supply shortages and what direction our business and family farm will take.”

Michigan’s Stage Nature Center, which works to preserve nature, agrees, and says its sap harvest has been affected by extreme weather over the last few years, and has been forced to make special provision to accommodate for a 70-degree day in February, and snow and 60-plus-degree days in March.  

Christina Funk, assistant naturalist at the center, says that the repercussions of fewer sugar maples will be widespread.

“Michigan's sugar maple trees are at the center of a multi-million dollar maple syrup industry. Maple syrup production has been important since before Europeans invaded the region and has played a major role in trade among Native Americans,” she says.

The sugar maple’s predicted decline is a big ecological and economical concern, Funk says. She advises us to do our bit to help save pancakes from mediocracy, by reducing our energy consumption, reusing where possible and recycling.

“Encourage the use of renewable resources, speak out to policy makers about the importance of conserving our natural resources, and educate others about the issue and what they can do to actively help improve the environment on a local and global scale."

There is one silver lining: Scientists are currently looking into alternatives, such as the red maple tree, which is thought to be less susceptible to climate change. In the meantime, thank God for peanut butter.

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