So what? 木 means wood now. (Well, no it doesn't. 木头 means wood now. 木 is not a word in modern Chinese.) It meant tree, which is relevant to the construction of 森, 本, 休, 树, etc.

It took me all of a few seconds to look up the proverb 独木不成林 "one tree alone is not a forest". What do you think the 木 means there?

> 木 is not a word in modern Chinese

Eh, 木 is used commonly by itself.

这张椅子是用木做的。 (This chair is made of wood)

Fair enough.

Maybe it's tongue-in-cheek, as the word for forest is made of two woods...