treetop 树梢;

branch 树枝;

twig 小树枝;

bough 大树枝;

leaf 树叶;

sapling 树苗;

tree root 树根;

bark 树皮;

pith 木髓;

annual ring 年轮;

stump 树桩;

trunk 树干;

taproot 主根;

sprout 新芽