The Science of Maple Sugaring

—Mary Gillick, Education Director

Photo: USA Today

Winter may have had a slow start this year and temperatures have just dropped to normal but the maple tree is not fooled since it is governed by the length of daylight. Like other deciduous trees it is dormant from October through February and conserves water by dropping its leaves.

The sapwood or xylem is found just under the bark and is constructed of cells that generally carry water up from the tree roots. In late winter the sapwood holds the sucrose mixture produced by the leaves during photosynthesis in the summer.

Sap may be collected from red and silver maples. Commercial producers harvest from the sugar maple (also known as rock or hard) since these carry the highest concentration of sugar in their sap at almost 2 percent.

Each tap on a mature tree yields about 10 gallons of sap which when boiled down produces about one quart of syrup. It takes 40 to 45 gallons to make one gallon of the delicious product.

A sap "run" occurs when day temperatures rise above freezing and cold night temperatures stop the sap flow. In February or March the process of transport begins in starts and stops as the weather fluctuates.

New leaf and flower buds formed during last summer's growth spurt are ready to take advantage of warmer days. As the sugary sap reaches the buds they swell and sugaring season comes to an end.

For more information, visit:
maple.dnr.cornell.edu