黄化

例句：

1. 1. The old tree is showing signs of yellowing due to age.
   这棵老树因年岁已久开始出现黄化的迹象。
2. 2. The soil in the garden has started to yellow, indicating a lack of nutrients.
   花园里的土壤开始发黄，表明缺乏养分。
3. 3. The chemical treatment for yellowing paint was effective in restoring its original color.
   针对发黄油漆的化学处理有效恢复了其原始颜色。