Reflections in Nature: Turpentine distilled from pine pitch
During my adolescent years, my mother often would tell me to take off my good jeans before I ruined them. While setting up our Christmas tree recently, I was taken back to those youthful days when my wife, Mary Alice, said, “Bill, take off those good jeans before you get pine pitch on them.”
When a cut is made into the trunk of an evergreen tree, pitch will ooze from the trunk. Although all conifers ooze pitch when injured, pine trees are well known for their resins.
A Greek legend is told about the forests being the home of nymphs and dryads (a nymph of oak trees) and many minor gods, including Pan and a goddess by the name of Pitys, who tended the pine trees in the forests.
Pitys also had a lover, Boreas, god of the north wind, a big and burly fellow who was quite different from the flute-playing Pan. Pitys flirted with both. One day Boreas got into an argument with Pitys about her flirting with Pan and became so enraged that he threw her against a rocky ledge, where she instantly turned into a pine tree.
From then on, the resin droplets seen on the wounds of pine trees were said to be the tears of Pitys remembering her youth.
When the trunk of a pine tree is cut or injured, it will weep glistening tears known as resin, pitch or gum. Resin is a honey-like mixture of hard rosin — a translucent yellowish to dark brown resin derived from the stumps or sap of various pine trees — and liquid turpentine.
The pine tree, which uses this resin to help heal its wounds, also has the ability to create an extra flow of resin to a wound by creating new resin canals above and below the injury.
This ability to create an extra flow of resin has been valuable to mankind. The turpentine industry is based on the emergency response of the pines. By putting carefully planned gashes in the turpentine tree, the resin can be gathered much like sap from maple trees.
Severe and frequent wounding could kill a pine tree; however, reasonable tapping once or twice a week is harmless and can be continued for many years. The total weight of the resin collected could be more than the weight of the entire tree.
Most conifers have resin canals; however, those of the pines are more efficient. The resin is known as oleoresin, a naturally occurring mixture of essential oils and resin, and each species of pine has its own particular oleoresin chemistry.
This chemical difference caused quite a stir during the Civil War. At the beginning of the war, when the Union Forces were cut off from their normal turpentine sources of the south, production began in the forests of California. Resin was taken from the Ponderosa pine and also, mistakenly, from the Jeffery pine, which resembled the Ponderosa. Both trees grew in the same area.
Ordinary turpentine was distilled from the Ponderosa pine; however, resin collected from Jeffrey pines contained heptane, the same highly inflammable heptane that is found in petroleum as it is pumped from oil wells. Firing a still loaded with pitch from the Jeffery pine compared to building a fire under a gasoline tank. Heptane had to be distilled very carefully.
In 1924, when the gasoline industry was trying to remove engine “knock” from their gasoline, they needed a supply of heptane for research work. Once again the Jeffrey pines were tapped. The octane rating scale for measuring the knocking quality of gasoline came from the Jeffrey pine.
Today, there is a less complicated and cheaper method of testing fuels.
I’m an impatient person, and it is hard for me to stand around waiting for decisions to be made; however, Mary Alice, who likes to have things done correctly, says to me “Fools rush in where wise men fear to tread.” I probably would have been the one that mistakenly tapped the Jeffery pine, but, in my defense, I would have been wearing an old pair of jeans.
Bower retired after 34 years as a wildlife conservation officer for the state Game Commission. Questions and comments may be sent to him at 1224 Redington Ave., Troy PA 16947.