Maple syrup is made from the sap of maple trees.
All species of maple trees yield sweet sap, but sugar maples have the highest concentration of sugar. Pure maple syrup is nothing more than tree sap that has been boiled. Boiling evaporates water from the sap, making it thicker and higher in its sugar concentration. The water is absorbed by a tree's roots and the sugar is produced by the leaves during photosynthesis. Each winter any sap not used for tree growth is stored in the roots and lower trunk.