The 2024 maple syrup season has "been a nail biter," says Jason Lilley, assistant extension professor and sustainable agriculture and maple industry educator with the University of Maine Cooperative Extension. Sugar maple trees are showing signs of stress from the changing climate, and sugarmakers are working with uncertainty with when to tap and for how long.
      The season has not had the traditional gradual warm up that makes for a good season, Lilley explains, which needs cold temperatures at night and day temperatures creeping up above freezing. Instead there was a warm spell and early start to the season in February followed by a freeze up. "There's a lot of variability across the state," and that includes neighbors who might have a sugar bush on south-facing versus north slopes.
      Pembroke resident Colin Brown has been tapping for maple syrup for 15 years. He started in Connecticut when he was working for a nature center and now taps from 12 to 15 red maples that belong to neighbors near his Pembroke property. Brown is the executive director of the Downeast Coastal Conservancy, and while he doesn't have a forestry background, he's attuned to the changes that are happening in the forests because of climate change. "The biggest change is uncertainty." When he was in Connecticut they would start tapping in February; now he relates that friends back in the state tell him they are tapping right after New Year's Day.
      This year Brown put his first tap in on February 8. Talking to people who remember the maple syrup season of 30 to 40 years ago, the first taps went in around March 1 and the season extended into mid April. The season has completely shifted, he adds.
      Brown is not worried about the health of the red maples he taps, but sugar maples, he says, are "a climate change migration species. They like cold winters and good drainage." Lilley states that sugar maples up around the Canada Quebec border have been fine, but those lower down in western Maine and along the coast have seen stresses that could be leading to decline.
      Red and silver maples help to take up the slack, with both producing sap for syrup. While it takes considerably more sap to make syrup with red and silver maples than with sugar maples, the trees withstand weather fluctuations more readily. Lilley, who works with agencies and institutions on maple research, notes that sugar maples have become stressed from periods of drought, heavy rains, lack of snow cover and high winds. The stress weakens the tree's ability to withstand disease and pests. The lack of snow cover allows the frost to penetrate deeply into the ground. The result is frost shearing of the tree's delicate feeder roots. They get cut off, he says, leaving the sugar maple without the root system that helps the tree absorb water and nutrients.
      Having a sugar bush stand that has about 25% intermixed hardwood and softwood species that are deeper rooted and help to protect and shelter the maples is one strategy proving to help, Lilley explains. For example, a study of a sugar bush stand showed that where a red maple stand broke up the sugar maple canopy, the damage caused by tent caterpillars was interrupted. "You break up the canopy with diversity so that bugs can't march along."
      Technological developments have helped the maple syrup industry keep up with demand, despite the concerns with the sugar maple stands. "Some of these tools are having huge impacts this year," Lilley says. Vacuum systems used with tube sap collection systems create a negative pressure to draw the sap from the tree. "I've been hearing that gravity systems are not drawing sap" this year. He adds that the University of Vermont Proctor Maple Research Center has been conducting research on whether vacuum systems are detrimental to the tree's health. There was no significant difference in the effect on a tree's health between a gravity and a vacuum system, he notes.
      Brown uses a simple gravity system for his syrup venture, with buckets made from plastic water jugs and food grade five gallon covered buckets to haul the sap by hand to his wood fired boiling system. A stalwart and rather magnificent old Glenwood wood stove that once belonged to his aunt now sits in a covered but open aired space where Brown can load it with firewood, pour in sap and strain off "sugar sand" during any kind of weather. He preheats the sap on propane to cut down on the time and wood he uses to boil it down, and fits the wood stove with a small evaporator pan. It's a system that works well for his needs, making enough syrup for his family and friends.
      "It's not a working man's hobby," Brown says with a laugh. He knows of a number of area residents and small farmers who tap for their own table. For Brown, it takes five to six days of day long boil downs, and that doesn't include the gathering of sap and cleaning up the yard for wood to split and use in the wood stove. "You don't want to know," he says of how many hours it takes. "But I love it."
      A few research projects are in the proposal phase that will be examining those areas in Maine suffering sugar maple declines, explains Lilley. The Maine Forest Service, the UMaine Cooperative Extension, the UMaine School of Forest Resources and more are involved. Understanding the importance of forest diversity is a key component to sugar bush health, he stresses.
      The UMaine Cooperative Extension is hosting the Downeast Agriculture and Forestry Conference on Friday, March 22, from 8 a.m. to 3 p.m. at the University of Maine at Machias. Lilley notes that one section will be about assessing sugar maple stands for potential syrup production. The event brings agricultural and forestry management experts from UMaine, local agencies and nonprofit organizations to Machias to share information with Washington County farmers, growers and forestland owners. Registration is recommended. For more information contact lily.calderwood@maine.edu.