outer dead bark

例句：

1. 1. The tree's outer dead bark is peeling off.
   这棵树的外层死皮正在脱落。
2. 2. The scientist found the outer dead bark of the plant to be rich in nutrients.
   科学家发现这种植物的外层死皮富含养分。
3. 3.The outer dead bark of the tree was so thick that it was almost impossible to remove.
   这棵树的外层死皮太厚了，几乎不可能被移除。