名詞 alder:

1. wood of any of various alder trees; resistant to underwater rot; used for bridges etc
2. north temperate shrubs or trees having toothed leaves and conelike fruit; bark is used in tanning and dyeing and the wood is rot-resistant
   同義詞：alder tree

1. Alder trees belong to the birch family.
   赤楊屬于樺木科。