Betula lenta as long as the tree lives, but the individual bark layers become indiscernible after roughly 250 years of age. "Betula lenta" was used commercially in the past for production of oil of wintergreen before modern industrial synthesis of the oil; the tree's name reflects the wintergreen scent of the shoots. The sap flows about a month later than maple sap, and much faster. The trees can be tapped in a similar fashion, but must be gathered about three times more often. Birch sap can be boiled the same as maple sap, but its syrup is stronger (like molasses). The leaves
Chrysolepis three sweet, edible nuts, eaten by the indigenous peoples. The fruit also provides food for birds and wildlife. "Chrysolepis" is related to the subtropical southeast Asian genus "Castanopsis" (in which it was formerly included), but differs in the nuts being triangular and fully enclosed in a sectioned cupule, and in having bisexual catkins. "Chrysolepis" also differs from another allied genus "Castanea" (chestnuts), in nuts that take 14–16 months to mature (3–5 months in "Castanea"), evergreen leaves and the shoots having a terminal bud. There are two species of "Chrysolepis" — "Chrysolepis chrysophylla" and "Chrysolepis sempervirens" — which like many species