This is a photo of the trunk of a cherry tree exuding modern day resin that one day might become amber.

Resin producing trees are thought to use their resin for a variety of purposes including protection from both external and internal insect infestations; to fill in internal cracks in the trunk and external wounds when the bark is taken off. The resin is analogous to blood, in that is acts as sort of a "clot" to protect against exposing its sensitive tissues to disease, insect attack, and the elements of nature.