木化

例句：

1. 1. The tree has been standing here for decades, and its bark is starting to 木化.
   这棵树已经站在这里几十年了，它的树皮开始变硬了。
2. 2. The wood was so dry that it had started to 木化.
   木头太干了，已经开始变得坚硬了。
3. 3. As the weather turned colder, the grass began to 木化.
   随着天气变冷，草地开始变硬了。