A mild winter means early start to maple syrup season
Quite a few of my friends have been grumbling about how they can’t wait for winter to be over and that they are ready for spring.
I was surprised by this. I feel the opposite. It feels to me like we haven’t really had much winter yet. I was even more surprised when my maple sugaring friends told me they had been tapping their trees for weeks … this seems awfully early to me, a late winter/early spring thing.
But it makes sense, the warm days and cold nights of the past week are prime tapping conditions. This year, we have had an abnormally warm winter, in fact, this has been a trend over several seasons, and so the timing of maple sugaring is having to shift accordingly.
According to a recent maple sugaring update from the USDA (“Northeast Maple Syrup Season Off to a Very Early Start” by Lori Tyler Gula), an early tapping season shouldn’t affect the amount of maple syrup produced by a tree unless there is an even earlier than normal spring warm up. What the industry and us backyard maple tree tappers need is a six- to eightweek period with robust freeze-thaw cycles. Typically, we might have a couple of days in January when temperatures top 40 degrees during the day. That is not a long enough period of this sort of fluctuation for good sap flow that usually happens later in the season. This year, however, the long-term forecasts predicted an early start to ideal sap flow conditions.
In winter, sugars are stored as more complex starch molecules in the woody cells surrounding the xylem vessels (tubes that carry water and nutrients up from the roots to the leaves). In the spring, as temperatures begin to rise, these starch molecules break down into sugar and are released into the xylem from the wood. The reason we need cold nights and warm days for good maple sap flow has to do with generating enough pressure in the xylem to start pushing its contents – the water and sugars – up from the roots.
In the early spring, the ground starts to thaw, and water begins to move into the roots, generating an upward pressure in the xylem. Cold nights compress gasses in the xylem and cause water to freeze along the inside of the xylem tubes. Warm sunny days melt the ice and cause the gasses in the xylem to expand, generating enough positive pressure in the xylem to cause the sap to rise. This is why a good freeze/thaw cycle is vital to maple sugar production - the bigger the difference in day/night temperatures, the more sap will flow.
I have been tapping maple trees for the past three years now. I am still learning. I don’t have big old sugar maples with their high sugar content (their sap contains as much as three percent sugar). I have red maples that grow down the hill from my house, along the river. Red maple sap is typically less than 2% sugar. The first year I tapped trees, I got enough sap to produce 10 pints of syrup. It was a lot of hard work mucking around in the dark (I had to do this after work), lugging heavy sap buckets up the hill, and getting creative with snowbank storage until I had time to boil it down (sap is like milk- it will go bad if stored in toowarm conditions). I think it was the most delicious maple syrup I have ever had, as is true of everything handmade, and easy enough to make to want to keep at it. Punxsutawney Phil predicted an early spring on Groundhog Day this year. I hope he is wrong. I hope for more winter and a nice long maple sugaring seasonlots of freezing nights and warmish days.
Susan Pike, a researcher and an environmental sciences and biology teacher at Dover High School, welcomes your ideas for future column topics. Send your photos and observations to spike3116@gmail.com. Read more of her Nature News columns online at Seacoastonline.com and pikes-hikes.com, and follow her on Instagram @pikeshikes.