名詞 heartwood:

1. the older inactive central wood of a tree or woody plant; usually darker and denser than the surrounding sapwood
   同義詞：duramen

heart.wood

n.（名詞）
The older, inactive central wood of a tree or woody plant, usually darker and harder than the younger sapwood.Also called duramen
心材，樹干：樹木或木本植物中較老的不再生長的部分，通常比樹齡短的邊材更硬且顏色更深也作 duramen