There are four different kinds of maple trees native to northeastern United States, all of which produce spring sap flows, can be tapped and will produce maple syrup. The Sugar Maple is the main maple producing tree. Also, the syrup made from the other saps are darker and less flavorful. Maple sap is thin, barely sweet, and as colorless as spring water. The distinctive maple taste comes only through boiling.
Maple sap is found in the living tissues of the roots, stems, twigs and trunk of the maple tree.
Sap flow is related to rising temperatures. Warming temperatures above 32 degrees F increases sap pressure. Sap runs in fits and starts from the first spring thaw until the buds turn into leaves from mid-March until April. A good maple season has warm days, but nights below freezing. They would use their tomahawks to make V shaped incisions in the trees, then insert reeds or concave pieces of bark to run the sap into buckets made from birch bark.