韧皮

例句：

1. 1. The tree's bark is thick and rough.
   这棵树的树皮厚且粗糙。
2. 2. The sapwood is soft and easy to work with.
   韧皮软且易于加工。
3. 3. The woodworker carefully strips away the outer layers of the tree to reveal the inner raywood.
   木工仔细地剥去树的外层，以露出内部的射线木。