WINTER HARBOR — If you want to know when maple sugaring season begins, look out the window.
The calendar no longer accurately predicts the best time to start tapping maple trees, according to Kathryn Hopkins of the Maine Cooperative Extension Service.
Hopkins spoke to 15 people about climate change and the maple industry during a March 21 lecture at the Schoodic Institute.
The good news is experts believe the sugaring industry will survive despite climate change. However, survival will require people to adapt.
Changing weather patterns have created ideal tapping conditions in January or February rather than the traditional time in mid-March. Those who tap early run the risk of their trees drying up before the end of the season. Likewise, those who wait until March to begin run the risk of missing some of the best tapping, Hopkins said.
Although climate change is a serious issue, Hopkins said it’s important to consider the full body of evidence rather than the conclusions of single studies.
“You can’t look at any one piece of analysis and conclude the sky is falling,” she said. “You can’t take any one piece as a prediction for everything.”
Some studies have indicated, for example, that in 20 years, the climate in Maine will be better suited to oak pine and oak hickory trees than maples.
“It doesn’t mean whatever’s already growing there won’t be there anymore,” Hopkins said.
Other studies have concluded that maple trees will continue to grow in the same areas but they may not be as healthy as those growing now.
“If the climate warms, we’ll have less snow,” she said.
In one study, scientists removed snow from around the bases of maple trees for four to five weeks in winter over a period of five years. This caused root damage and the trees experienced 40 percent less growth than trees from which snow was not removed.
“They don’t recover,” Hopkins said.
Warmer climates also mean more insects that feed on tree leaves are likely to survive winter. If they defoliate a tree as the leaves sprout, the tree will be forced to use extra resources to grow new leaves.
Fungal diseases also grow and spread better when spring is cool and moist, she said.
Trees are also likely to become stressed from drought, frost, injuries from ice and increases in human population and associated development.
An increase in wind is another issue.
“Even if just breaks branches off the trees, now you have a point of entry for insects and diseases,” Hopkins said.
How sap quality will be affected by the changes is unknown. The maple industry may have to compensate by changing its recipes or using more sap.
Hopkins advised even those not certified organic to use organic practices because they are healthier for the trees.
It’s also advisable to keep the sugar brush area as diverse as possible by planting and maintaining multiple varieties.
“Keep those seed producers going and when the seed producers die off, let them stand,” she said.
As long as the tree is not likely to fall and cause damage or injury, it will serve as a nesting place for birds and a source of food for woodpeckers.
Hopkins said new technology may also be developed to maximize sap yields and keep trees healthy. Growers need to be open to the change it may bring.
“There’s a lot of unknowns, but we will still have an industry,” she said.
For a complete list of upcoming Schoodic Institute lectures, visit schoodicinstitute.org.