The inhabitants of far northern parts of the globe, including Alaska and Scandinavia, have long made a sweet syrup from the sap of birch trees, various species of Betula that are the dominant forest trees in northern latitudes. Birch sap runs for two to three weeks in early spring. It is much more dilute than maple sap, around 1% sugars, mainly an even mixture of glucose and fructose. It takes around 100 parts of sap to make 1 of syrup, both because there’s less sugar to begin with, and because a mixture of glucose and fructose is thinner than the equivalent amount of sucrose; producers therefore aim for a final sugar concentration of 70–75%. Thanks to the different sugars and their reactions, the syrup is reddish brown and has a more caramel-like flavor than maple syrup; the level of vanillin is lower, too.