The name 'Bird's Eye Maple' refers to the twisting of the silver grain, which produces numerous knots like the eyes of birds. Considerable quantities of this Maple are imported from Canada for cabinetmaking. The wood forms excellent fuel and charcoal , while the ashes are rich in alkaline principles, furnishing a large proportion of the potash exported from Boston and New York. Large quantities of sugar are made from the sap of this species of Maple. The sap is boiled and the syrup when reduced to a proper consistence is run into moulds to form cakes.
Trees growing in moist and low situations afford the most sap, though the least proportion of sugar.
The trees are tapped in early spring, just before the foliage develops, either by making a notch in the stem, about 3 feet from the ground, with an axe, or by boring a hole about 2 inches deep and introducing a spout of sumach or elder, through which the sap flows into a trough below. The sap is purified and concentrated in a simple manner, the whole work being carried on by farmers, who themselves use much of the product for domestic and culinary purposes. A cold north-west wind with frosty nights and sunny days tends to incite the flow, which is more abundant during the day than during the night. The flow ceases during a south-west wind and at the approach of a storm, and so sensitive are the trees to aspect and climatic variations that the flow of sap on the south and east sides has been noticed to be earlier than on the north and west sides of the same tree. The sap continues flowing for five or six weeks, according to the temperature.