stump bur

例句：

1. 1.The tree was so old that it had a stump bur.
   那棵树太老了，有一个树桩。
2. 2. The stump bur was covered in moss and lichen.
   树桩被苔藓和地衣覆盖着。
3. 3.The locals used to dig up the stump bur for firewood.
   当地人过去常挖树桩当柴火。