Phonosemantic compound. 木 represents the meaning and 者 represents the sound. Originally written as 耂, which is a pictograph of a tree with paper mulberry leaves.

Evolution

Bronze script

Late Western Zhou (~800 BC)

Seal script

Shuowen (~100 AD)

Clerical script

Cao Wei (Three Kingdoms: 222-280 AD)

Regular script

Modern

 More