And now an entire industry is trying to understand how the climate and weather patterns affect temperatures in maple regions, to see what’s in store for this North American staple.

That includes researchers like Adam Wild, who wants to know exactly what’s in store for this sugary, natural, household good. As the director of Cornell University’s Uihlein Maple Research Forest, Wild helps oversee research across a more than 200-acre forest in Lake Placid, New York. The land is used to assist researchers with finding ways to grow the maple industry, especially in the Northeastern United States and Canada.

New York has the most tappable maple trees in the US, and its large size and (previously) ideal winter climate all contribute to helping it produce good sap flow, especially in the upstate western portion and the Catskills. There’s typically a four-to eight-week window for collecting sap here.

“Last year, northern New York was a little too cold sometimes so western New York did better with sap,” Wild says. “Sometimes you have below production [with sap flow] and other years it will be the opposite.”

To be good, maple trees need to freeze. Mild winters and sudden warming periods aren’t necessarily unheard of in maple-producing areas, but the frequency of such periods in the past few years is increasing.

Maple trees require below-freezing nights to help them recharge. As the chilly evenings approach, the trees absorb groundwater, ideally through thick snow layers, through their roots. The cold temperatures freeze the water inside before it’s thawed out in the day, with positive pressure pushing the sap out. This natural process encourages strong, healthy sap flow with bountiful sugar content.

But it’s a delicate process that can be ruined by higher temperatures.

“Sap can spoil sooner and will spoil if not processed right away,” Wild says. “With warmer weather it’s harder to keep sap fresh.” This could lead to partially spoiled batches or off flavors, like mustiness and sourness.

Traditional maple syrup-producing areas are already seeing the effects of these weather shifts. Last year, for example, Vermont produced 20 percent less syrup than in 2022, in part due to an erratic winter that swung from mild temperatures to extremely cold ones.

A changing climate is also impacting the harvest. The traditional harvesting window is usually late February to early April throughout the Northeast. But in southern or midwestern states, tapping can begin months earlier.

In Virginia, Kevin Connor, owner of Mill Gap Farms, tends to 3,000 taps on his USDA-certified organic farm in Highland County.

Mill Gap Farms was the first to tap in Virginia this year, although Connor believes they could have done so even sooner. “We had a good harvest but quite possibly a little better if we were two to three weeks sooner. However, there is a trade-off for that earliness,” he says. “Given our latitude, the tap holes will only last so long, even under vacuum. Each year is different for sure.”

Connor hasn’t noticed any major environmental changes as of now. “Weather is always going to be different and that’s what makes sugaring fun. We are always watching the weather, like my grandfather who raised tobacco would do,” says Connor. “He would sit on the edge of the sofa looking at the evening news when the weatherman came on. Today, we have some good apps that will give us a little insight about five days in advance, and that helps set our work schedule.”

But change is on the way. As average temperatures trend upward, one or two degrees every decade, frigid nights are declining. Sugarers need to act early and quickly if they hope to catch sap.

“We have definitely noticed harvest changes due to environmental impacts,” says Sam Hart, a second-generation maple farmer at Maplewood Farms in Brownsville, Indiana. “This year especially we noticed how early the season ended. We didn’t get the yield we were hoping for.”

Indiana’s maple season would typically last into March, but this sugarer has seen it barely go through February in the past few years. Because of this, tapping now starts significantly earlier. “We start tapping in December and essentially shift our sap collection season up a month or so,” says Hart. “This helps to avoid getting ‘buddy’ sap near the end of the season, which occurs as soon as the trees start to bud and gives the sap a sour taste.”

Because Virginia and Indiana lie on the edges of the country’s maple production area, it’s more likely that these states will be the first to experience negative effects thanks to increasing temperatures. A 2019 study estimates that by 2100, much of their maple syrup production will have virtually disappeared.

While mild winters are the main nemesis for maple producers, researchers are also cautiously looking at other factors, like if extra wet summers could affect long-term growth or how pests (like the spotted lanternfly) and diseases could impact maple trees and forests.

Despite all these concerns, sugarers are learning to adapt. “A lot of these producers come from generational farms so they know what their father or grandfather used to do 30 to 40 years ago,” says Wild. “Now it’s getting out there and tapping sooner, especially the last two maple seasons which really pushed that more.”

There is at least some good news, though. A changing climate might make some syrup better. “When compared to maple syrup made further north, I’ve found that syrup made in the midwest tends to have a more robust maple flavor,” Hart says. “We mostly make darker grades of syrup due to warmer winter temperatures. This lends itself to syrup with a high mineral content and a unique and delicious flavor.”