树 (shù) means 'tree.' It is the basic and most common word for a tree in Chinese. It can be combined with other characters to form compound words like 树叶 (tree leaves) and 树林 (forest).
这棵树已经长了一百多年了。
Zhè kē shù yǐjīng zhǎng le yībǎi duō nián le.
This tree has been growing for over a hundred years.
孩子们喜欢在树下面玩耍。
Háizimen xǐhuan zài shù xiàmiàn wánshuǎ.
The children like to play under the tree.
秋天的时候,树上的叶子都变黄了。
Qiūtiān de shíhou, shù shàng de yèzi dōu biàn huáng le.
In autumn, the leaves on the trees all turn yellow.