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Nature Notes: The Sugar Maple

Ed Robinson
March 20, 2018

When harsh winter cold grips the forest in January, most folks hunker down indoors to read a book, or to get started on their taxes. But for some hardy souls, winter is a time for hard work in the woods and watching the weather reports, anticipating the inevitable thaw that brings day time temperatures above freezing. If you have a sweet tooth, you surely look forward to the production from those woods warriors: maple syrup.

While syrup can be made from the sap of a number of species including birch, ash and black maple, the sugar maple is the undisputed king of syrup. A healthy tree can produce many gallons of clear sap with a high sugar content and wonderful flavor. In recent years, the sap itself has gained a following as an organic health drink, with some claiming it boosts the liver and kidneys. For most of us, the ultimate gift from the sugar maple tree is a stack of homemade buckwheat pancakes or a bowl of vanilla ice cream with that golden brown, sweet topping running down the sides.

The scientific name for the tree (Acer saccharum) comes from the Latin word for sugar. Native to the hardwood forests of Eastern Canada, and the northern US from Maine as far west as Minnesota, the tree is sometimes called rock or hard maple. In all of these areas, the tree can be a major component of the forests, and is valued equally for its sugar production and its beautiful, light colored timber. The trees have long been popular for landscaping because their dense foliage offers shade in the summer, and a stunning array of autumn colors from bright yellow through orange to radiant red. No one could cast their eyes over a New England forest during leaf season and not be captivated by the hues this wonderful tree brings to our region.

Unlike its faster growing cousin, the red maple, the sugar maple takes its time in adding mass, often due to its ability to grow under the forest canopy of larger trees. That slower growth rate results in a dense, heavy wood and trees that may live to 400 years in ideal conditions. While the tree normally reaches a diameter of 20 to 30 inches and a height of 70 feet, exceptionally large specimens have been found with trunk diameters up to six feet and topping out at 130 feet tall. The leaves have five sections, or lobes, with deep notches between them and sharp points. Leaf buds are brown and pointed, while new twigs start life as green and mature into darker browns. Young trees generally display pale, mostly smooth bark but as they age, the bark turns to darker gray with deep furrows.

The tree is tolerant of a wide range of soils except sand, and reaches maturity after 10 to 14 years in good conditions. After a few warm days in early spring, flowers appear in clusters of five to 10 yellow/green blossoms. As summer progresses, the fruit of the maple develops as a tan-colored seed with two wings (it’s known as a “samara”) about one inch in length. As summer turns to autumn, a wind will shake the samaras loose and they flutter to the ground, where they feed the local squirrels and set the stage for germination after a cold winter breaks down the seed’s outer coating. In winter, the tree buds provide nutrition for moose, deer and snowshoe hares.

Timber from this tree is one of the most popular hardwoods, because of its strength and durability, and for the light color with occasional mineral streaks. Some trees produce wood with waves in the grain, resulting in highly desirable curly or birds eye maple. Native Americans used the wood for hunting bows, and the inner bark for a tea to treat coughs and digestive problems. Early European settlers used hard maple for making sleighs, sleds and buggies. Today you can find the wood everywhere from paddles to bowling alleys (the floors and pins), from kitchens to basketball courts, violins and guitars and increasingly in baseball bats as white ash trees are decimated by the emerald ash borer.

Sugar maples have a dense network of roots, some shallow and some going deeper into the ground where they access essential water. Using a process called hydraulic lift, the maple draws that water into the upper layers of soil and helps sustain other plants around the base. That pumping system is key to the production of sap in the late winter and early spring. When the days approach 40 degrees, starches stored in the sapwood during autumn begin to turn into sugars, mostly sucrose. Rising temperatures trigger a hydraulic pressure in the tree and the rising water causes sweetened sap to flow to the upper parts of the tree. When a hole is drilled in the trunk and a tap installed, sap is available during day light hours, sometimes as much as 80 gallons during a season that can stretch four to six weeks in good years.

In New York, my friends and I tap 20 to 40 old sugar maples each spring, collecting the sap on ATVs or snowmobiles depending upon the snow depths. Then the work of boiling down the sap begins. Studies have shown the sugar content of sap can vary from 1.5 to eight percent, so we have to remove a lot of water to make our targeted 15 gallons of maple syrup. It takes a good deal of energy to make the boil, and a strong back if you are using firewood instead of fossil fuels. Most commercial operations, and many hobbyists, now use a reverse osmosis unit to remove 50 to 60 percent of the water before starting to boil, saving time and money. You can make your own syrup at home, but it’s recommended to do the boiling outside or you will have an excess of humidity in your kitchen. You’ll need a good stainless steel pot, accurate thermometer, hydrometer, filters and sterile jars for storage.

As a mark of its popularity, the sugar maple has been designated the state tree for four states; Vermont, New York, Wisconsin and West Virginia. Maine selected the white pine, but sugar maples still play an important role in our forest habitats, and maple syrup is a multi-million dollar industry in our state. In some parts of its range, the sugar maple has suffered decline due to acid rain, soil acidification, over cutting of mature forests and excess use of road salt. That salt intolerance has led to the expanding use of Norway maple for landscaping purposes, a growing issue because this invasive tree produces large volumes of seeds and can crowd out native species.

Now’s the time to plan on attending a local pancake breakfast, and be sure to give a sugar maple tree a big hug. Maine Maple Sunday is always the fourth Sunday in March and some sugarhouses offer events on both Saturday and Sunday. Click here to find a sugarhouse to visit. You won’t regret it!

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