spring layer

例句：

1. 1. The tree's leaves are changing from green to yellow in the spring layer.
   这棵树的叶子在春天的层次中从绿色变为黄色。
2. 2.The scientist observed the changes in the ecosystem during the spring layer.
   科学家观察到了生态系统在春天层次的变化。
3. 3. The artist painted a series of paintings that depicted the spring layer of nature.
   艺术家绘制了一系列描绘自然春天层次的画作。