sōng
pine tree
Phonosemantic compound. 木 represents the meaning and 公 represents the sound. In simplified Chinese this character also means "relax, loosen", but in traditional Chinese this meaning is written as 鬆.
Evolution

Bronze script
Mid Warring States (~300 BC)
Seal script
Shuowen (~100 AD)
Clerical script
Jin dynasty (266-420 AD)Regular script
ModernDefinitions
Sources