What is wood resin?
Pines contain numerous vertical and radial resin ducts scattered throughout the entire wood. The accumulation of resin in the heartwood and resin ducts causes a maximum concentration in the base of the older trees. Resin in the sapwood, however, is less at the base of the tree and increases with height. Natural resins are water-insoluble mixtures of compounds, many of which have a hydroaromatic structure. Mixtures of isomeric carboxylic acids, such as abietic and pimaric acids, which occur in rosin in nature in solvent-free form, in the form of tree sap or wood rosin such as pine oleoresin, where they are dissolved in terpenic hydrocarbons. They can also be present as fossil coal or copal resins, in old pine tree stumps, etc.
