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by Kevin Strauss
If you live near mature maple trees, you might have noticed some of your trees sprouting buckets this spring. While sports teams have basketball season and baseball season, nature has its seasons too and this is maple sap season in the northland. Human "sap tappers" take their electric drills into the "sugar bush" (maple stand) and drill small holes into sugar and silver maple trees. Then they tap in a metal spigot and hang buckets on the trees to collect the sap that drips out.
The reason that we tap maple trees in spring is because now is when the sugary sap is rising in the trees. Last summer, maple trees (actually all trees) turned sunlight, soil, water and carbon dioxide into a sugary liquid through the magic of green plant photosynthesis. Trees use that sugar as their food source and store extra sugar in their roots for the winter. Right now, the maples are pumping that sugary sap (about a three percent solution) into their branches to start the process of bud opening and leaf growth. The temperature changes from freezing nights and 40-degree days help the trees to pump the sap up to their branches. You also need relatively clean air for the trees to thrive. In New England, acid rain from Midwest power plants has cut maple growth by 25 percent and sapling survival by 85 percent, worrying sap tappers.
But upwind of such problems, tapping maple trees is a sustainable way to get resources from the trees since old tap holes heal over each year. But collecting the sap is only the first step to making syrup. Once tappers collect the dripping sap, they need to boil it down on the kitchen stove or over an outdoor fire. In the large maple forests of Vermont, sap tappers set up a "sugar shack" where they boil down the sap in huge metal pans. It takes about 40 gallons of sugar maple sap to produce one gallon of maple syrup. The final syrup is about 63 percent sugar, 35 percent water and a few trace acids.
Since it can be a lot of work to collect buckets of sap, expecially when you have to trudge through a foot of snow to do it, big tapping operations have gone "tubing." Tappers run brightly colored rubber tubes to each of the maple trees in their sugar bush. These tubes often drain downhill to the sugar shack or a collecting station on a main trail. Now that might seem like a lot of work to get one gallon of maple syrup, but if you tap paper birch trees in the spring, it takes 60 gallons of sap to produce one gallon of syrup. While much of our region is a bit too cold for sugar maples to prosper, it is just fine for silver maples, especially in towns. While silver maples donÕt have as sugary a sap as sugar maples, they are better than most other trees.
Of course people aren't the only ones who eat the syrup. Red squirrels will chew into the bark on a sugar maple and lap up the sap that dripps out. Insects like the mourning cloak butterfly will also lap up sap from broken branches or sapsucker holes.
While we do have artificial maple syrup these days, some folks swear by the "real stuff." So the next time you are outside, look for the "hand shaped" leaves of our local maples.
The Ely Timberjay
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