Stump-Harvest Time in Nicaragua
By “Awake!” correspondent in Nicaragua
A STUMP harvest? I had heard of harvesting such products as peanuts and pearls, even forests, but never a stump harvest. How do you “harvest” stumps?
The lumber companies, for the most part, have moved on, leaving in their sawdust trail mute reminders of a once-stately pine forest—naked and lowly stumps. Naked, yes, and lowly, but by no means worthless! These stumps are responsible for one of the largest industries in Nicaragua, the manufacture of rosin, turpentine, dipentene and pine oil.
On arriving at the plant, I found it quite obvious why it was called a stump plant by the local inhabitants. There, scattered over several acres, was a stockpile of about 15,000 tons of stumps.
Preparing such stumps for harvesting begins when the trees are felled by the lumbermen. From then onward, time must be allowed for a chemical action to occur. The outer layer must rot away while the raw materials remain locked in the wood fibers of the remaining part of the stump. This chemical and drying process requires from ten to fifteen years in northern climates but only from seven to ten years here in the tropics. Then the stump is ready for “harvesting.” A tractor pushes it out of the ground. The stumps are loaded on trucks and transported to the plant.
The stumps are first put through a huge grinder where they are reduced to chips. These are placed in an extractor, which is similar to a pressure cooker. A petroleum solvent is pumped into the extractor to wash through the chips, thus extracting the raw materials.
In another building the solvent is removed or separated from the crude material by steam distillation. The solvent is then condensed back to liquid and returned to storage tanks, where it will be used to start the cycle over again. Meanwhile, the crude material flows to a tank where the oils are separated from the rosin.
The turpentine, dipentene and pine oil have different vaporizing temperatures. They are separated by steam distillation by maintaining a certain temperature level until the first oil is vaporized; then the temperature level is raised until the following oils, each in turn, are driven off as vapors. As the separated oils each come off in the form of vapor they are cooled and stored in their respective tanks.
The rosin and dipentene are exported. Rosin is used in varnish, printing ink, soap, adhesives, and to rosin the bows of string instruments. Dipentene is in demand in making paint thinner. The turpentine and pine oil are, for the most part, consumed locally. Perhaps you associate turpentine with cleaning paintbrushes, but it is also an ingredient in the manufacture of insecticides. Pine oil is used in disinfectants.
As I gazed over the vast area of rolling plains generously seeded with black stumps, it became vividly apparent that stump harvesting will be a prosperous industry for some time to come in Nicaragua.