outer covering of tree trunk

• 树干的表皮

outer covering of tree trunk的用法和样例：

例句

1. Photograph by Joel Sartore A gecko sheds its perfectly camouflaged skin on a tree branch in Madidi National Park, Bolivia.
   在玻利维亚的马迪迪国家公园里，树枝上一只壁虎正蜕出它那极具伪装性的表皮。