sweet-water sap of certain North American maple trees, chiefly the sugar maple, Acer saccharum, but also the black maple, Acer nigrum. The sweet-water sap from which maple syrup is made is different from the circulatory sap of the growing tree. When the tree is dormant, the sap will flow from any wound in the sapwood, such as a taphole, each time a period of freezing is followed by a period of thawing. The sap contains 1 1/2 to 3 percent solids, mostly sucrose, but does not contain the colour or flavour of maple syrup, which are imparted to the sap as it is concentrated by evaporation in open pans. About 30 to 50 gallons (115 to 190 litres) of sap yield one gallon of syrup. The syrup season begins in mid-January in the more southerly areas and ends in mid-April in the northern regions, lasting four to six weeks in each place., suc de l'érable utilisé comme composant du casing