tree vs heartwood

tree and heartwood both are nouns.

tree (noun)	heartwood (noun)
a tall perennial woody plant having a main trunk and branches forming a distinct elevated crown; includes both gymnosperms and angiosperms	the older inactive central wood of a tree or woody plant; usually darker and denser than the surrounding sapwood
a figure that branches from a single root

tree (verb)	heartwood (verb)
force a person or an animal into a position from which he cannot escape
plant with trees
chase an animal up a tree
stretch (a shoe) on a shoetree