Resin Exudation

the abundant flow of resin from coniferous trees. Resin exudation is caused by wounds, burns, unfavorable growing conditions, and injuries produced by fungi (Cronartium flaccidum, Peridermium pini) or insects (bark beetles). The resin, or sap, flowing out of the resin passages drips onto the trunk and accumulates under the bark. It saturates the sapwood or covers the surface of the injured woody tissue, thereby protecting the tree against unfavorable elements. Resin exudation is very pronounced in young trees. It may be induced by tapping to obtain oleoresin.