在树后面用英语可以说作 "behind the tree"。这个说法来源于英语中表示位置关系的语法结构，即在某物之后、之前、之上、之下等。下面是一些例句：

The cat is hiding behind the tree.

I left my umbrella behind the tree.

Don't go behind the tree; it's dangerous.

We sat down behind the tree to have a picnic.