lignification

例句：

1. 1. The tree's bark is undergoing lignification as it ages.
   随着树木年龄的增长，它的树皮正在发生木化。
2. 2.During the process of lignification, the cellulose in the plant is converted into lignin.
   在木化过程中，植物中的纤维素被转化为木质素。
3. 3.The lignification of wood is a natural process that occurs during the growth and development of trees.
   木材的木化是一个自然过程，发生在树木的生长和发育过程中。