树叶 (shùyè) means 'tree leaves' or 'foliage.' It is a compound word combining 树 (tree) and 叶 (leaf). Use this word when specifically referring to the leaves of a tree, as opposed to leaves in general.
秋天一到,树叶就开始变红了。
Qiūtiān yī dào, shùyè jiù kāishǐ biàn hóng le.
As soon as autumn arrives, the leaves start to turn red.
地上铺满了金黄色的树叶。
Dì shàng pū mǎn le jīnhuángsè de shùyè.
The ground is covered with golden yellow leaves.
风一吹,树叶沙沙地响。
Fēng yī chuī, shùyè shāshā de xiǎng.
When the wind blows, the leaves rustle.