The camphor tree is an evergreen that is native to the far east.  It is now cultivated in many tropical and subtropical regions for wood and medicinal uses.  Camphor can be extracted from leaves and roots without long term damage to the tree. 

Camphor acts as an analgesic (pain killer), antiseptic, and as an counterirritant--reducing pain, swelling, itching and other discomforts.  Camphor also acts as a stimulant to contacted areas--potentially speeding healing and milk flow in congested udders.

http://www.innvista.com/HEALTH/herbs/camphor.htm

http://en.wikipedia.org/wiki/Camphor