Sapwood

Yew wood is reddish brown (with whiter sapwood), and is very springy. It was traditionally used to make bows, especially the longbow. Ötzi, the Chalcolithic mummy found in 1991 in the Austrian alps, carried an unfinished longbow made of yew wood.

Put simply, this is accomplished by the tree annually packing redundant sapwood with resin.

Cambium: The layer of living tissue [typically green] between the sapwood and the bark.

The larvae of Pine weevils feed on the sapwood of the leaders. The leader is killed and the shoots replacing it are distorted. First symptoms are pearl white drops of resin on the leaders.

See also: Trunk, Tree, Insects, Bark, Plant