growth ring boundary

例句：

1. 1.The growth ring boundary is a crucial indicator of the tree's age.
   生长环界线是判断树木年龄的关键指标。
2. 2.The research team focused on studying the growth ring boundary in ancient trees.
   研究小组专注于研究古树的生长环界线。
3. 3.By analyzing the growth ring boundary, scientists were able to determine the age of the tree.
   通过分析生长环界线，科学家能够确定这棵树的年龄。