For maple syrup producers in New Hampshire, the weather in February and March will make all the difference between a good season and a bad one.
Sugar maples grow from Quebec all the way down to South Carolina, and, given the right conditions, each region has a window of time in which sap extraction is possible. In order for sap to be collected, tapped maple trees need to have a period of freezing temperatures during the night that then rise above freezing during the day. They need the weather to gradually warm up as spring approaches. Major spikes in temperature will lead to a disruption of sap flow and a less-profitable season, as will weather that’s too warm or too cold.
So, what’s the future of syrup season in a changing climate? Peterborough resident and UNH Cooperative Extension forester Steve Roberge believes we will still “have weather conducive to sap flow, but it will likely be earlier and shortened.”
Roberge taps sugar maples on a small scale in Peterborough.
“As a forester,” he said, “I like to watch the trees wake up.”
This “waking up” process allows sap, containing water, sugars, nutrients and starches, to start to flow up from the roots of the trees. A lot of energy is required for trees to unfurl their leaves, and the movement of sap up to the opening buds is essential for this process.
In 2021, most syrup producers in the area had a difficult year. It was too cold and then it warmed up too fast.
“Last year, most people made 60 to 65% of a crop,” said Ben Fisk, owner of Ben’s Sugar Shack in Temple. Ben’s starts tapping the first week of January, earlier than most smaller-scale operations. The business has 32,000 taps in New Hampshire, so it’s worth it to get a head start in case there’s an early thaw, and with the challenging season last year, it hopes to have a bigger crop this spring.
With its large distribution, Ben’s Sugar Shack purchases syrup from other producers to supplement what it taps from its own trees, and each of its bottles lists where the syrup was sourced. But this is the first year it has had to purchase syrup internationally, from Canada, to keep syrup on the shelves of one of its retailers. Producers in New England and the United States just didn’t make enough last year, leading to a national maple syrup shortage now that the stocks have run low.
Even with uncertainty around what the weather will look like in the next few months, Fisk said he is hopeful for a good season. He believes the amount of rain that fell last summer and the cold temperatures this winter are good signs, but, he added, “We won’t know what the crop looks like until May.”
The weather during sugaring season has the biggest and most-obvious impact on sap production, but there are longer-term environmental factors that haven’t been studied in depth yet. Years with drought puts stress on trees and impacts their overall health, Roberge explained, and “there is 11 inches less snow on the ground than there was 50 years ago.”
Roberge added, “Snow is a really good moderator of temperature, and with a smaller snow pack and with snow that is melting more quickly, it’s hard to know what the exact effects will be in the years to come.