FOREST BY-PRODUCTS The Naval-Stores Industry. Turpentine gathering in the longleaf pine woods began with the settlement of the country, and forms one of its greatest forest industries. Vast quantities of tar, rosin and turpentine have been consumed, chiefly in ship yards in this and other countries, until the steel craft replaced the wooden. Now other industries consume the surplus output of these turpentine orchards.
A pocket several inches wide and deep is cut near the base of a tree. It holds two or three pints of the resin.* The bark and the outer wood to the depth of an inch are chipped off for a consider able distance above the pocket. The exposed wood bleeds resin, which is regularly dipped from the pocket by a man with a ladle * Rt,irt is the crude liquid ; rosin is the hard, brittle substance left after the turnentine is curactcd.
and a pail, who gathers the flow and carries it in barrels to the still. Once a week from March till November the chipping is repeated, and two inches are added to the height of the chipped area. If this fresh wounding did not occur, the flow would cease by the hardening of the resin.
One man tends ten thousand "boxes," and should get forty barrels at each round, or "dip." Eight to ten circuits are made for collecting in the thirty-two weeks the resin flows. The hard gum that accumulates in cold weather is also gathered. The yield of "dip" to "scrape" in this first season is as four to one. As the trees are drained, the surface exposed, becoming larger, yields more of the hardened gum, and the grade of the products deteriorates. The fourth year the orchard is abandoned by the largest operators, who move to pastures new. Small owners box their trees much longer, rest them a few years, then box again on bark before untouched.
In the still, the resin is melted and the volatile turpentine driven off and collected in barrels. The fire goes out and the residue in the retort is drawn off through strainers into barrels, where it solidifies when cool into rosin. The price of turpentine varies from twenty-eight cents to forty cents per gallon; that of rosin is about $2 per barrel.
The wastefulness of the old boxing methods shocks every intelligent observer. Better ways are being introduced, which, while more expensive, yet pay for the trouble in the generous increase in yield and the improving of the quality of the turpentine and rosin. The cup devised by Mr. Schuler (see Bulletin i3, Division of Forestry) takes the place of the deep, injurious pocket made in old-fashioned boxing and does away with dirt and chips in the crude turpentine.
While the timber is not directly injured by the boxing, the pine orchards fall a prey to fungi and insects, the trunks are weakened by deep boxes, and the wounds destroy the cambium, semi-girdling the trees and necessarily lowering their vitality.
The demoralised condition of an abandoned orchard under the ordinary careless management points to the trees' early death.
Pine tar has long been extracted from the longleaf by piling dry wood, limbs, roots, and stumps, cut in small sizes, closely in a clay-lined pit, covering it with sods and earth, and burning it with smenldering fires lit below at small apertures. A passage way provided from the pit leads the oozing resin to the barrels. After a week or more this pine tar begins to flow and continues for several weeks. The quality is much lower than that produced in retorts, for it is mixed with dirt. Boiling down pine tar until it loses one-third its weight makes a sticky mass called pitch. The wood in the pit is transformed into charcoal.
This pit method of extracting tar and making charcoal is a crude prototype of the process of dry or destructive distillation of wood.
The Dry-Distillation Process.—What the oil mill is to the cotton field the still is to the forest. Its work is to dispose of the refuse and to turn it into gold. Crooked branches, knots, root stubs—sound wood the lumberman ignores—is cut up and packed into a retort. A furnace underneath heats this air-tight chamber to 600'–fioo° F. The water goes off as steam in a coil or worm, upon which cold water is played in order to cool and condense its contents. A wood gas is next driven off. Then a brownish liquid flows out. This contains wood vinegar, used extensively in dyeworks, and acetic acid, which is made into vinegar. There is also present wood alcohol, useful to the manufacturing chemist, and in many other industries. Tar and creosote are also yielded by maple, beech, and birch, the preferred woods at the regular acid mills. After twelve hours, the retort is emptied and refilled. The wood is found to be transformed into charcoal. Many acid mills are located in New York and Pennsylvania.
In the longleaf pine woods the crooked, knotty top stuff and root stubs are the richest in resin. These yield in distillation the greatest quantity of tar and turpentine and the highest qualities of these products, also the best charcoal. Beside this process the old method of burning the wood in kilns or pits in hillsides and ladling the tar into barrels was most slovenly and wasteful. Many valuable volatile substances that are now captured in the coil formerly escaped in smoke.
The most remarkable invention is a method by which ethyl alcohol, the highest grade known, is derived by distillation from sawdust, and an equally high grade of charcoal is left. It is the Classen method, introduced from Germany a year ago, and it promises to utilise the greatest nuisances of the sawmill, the sawdust and slabs.