Issue Date: December 15, 2014
Change Comes Slowly In Pine Chemicals
Pine tree resins are arguably the oldest corner of the chemical enterprise. In the Bible, when God instructed Noah to “pitch the ark within and without,” he was talking about pine sap or gum. And pine chemicals, sometimes called “naval stores,” were bought and sold by seafarers back in Greek and Roman times.
The harvesting of pine gum has changed little since then. Tappers head into the forest, cut gashes into pine trees, leave while the gum oozes out, and come back later to collect it for sale to a distillation plant.
The process’s labor intensity doomed the industry in the U.S. and is threatening it today in other parts of the world. But advocates for pine chemicals are trying to introduce modern farming and harvesting techniques to keep the industry alive—and perhaps even reintroduce it to the U.S.
As late as the 1960s, the U.S. was a major producer of rosin and turpentine distilled from pine gum, recounts Charles W. Morris, president of the Pine Chemicals Association, based in Fernandina Beach, Fla. But as the country industrialized, fewer and fewer people were willing to engage in the unpleasant work of pine tree tapping. At the same time, a new source of pine chemicals emerged as pulp and paper mills began collecting the pulping waste they previously poured into rivers and streams.
Chemicals from paper pulping grew into a large industry that still thrives in the U.S. today. But the tapping of live trees slowly faded out. The last pine gum distillation plant, an AkzoNobel facility in Baxley, Ga., closed in 2001.
Today, China is the world’s largest pine rosin producer, accounting for more than half of the 1 million metric tons or so produced each year, according to Alejandro Cunningham, a consultant who has been in the pine chemicals industry since 1979. Applications include adhesives, printing inks, and chewing gum.
Yet China’s pine chemicals industry is threatened by the country’s own rapid industrialization and the move of rural citizens into cities. Rosin output barely passed 500,000 metric tons last year, well off its peak of 800,000 metric tons in 2006.
Morris and Cunningham point to Brazil as the home of the most forward-thinking pine tappers. There, companies such as Resinas Brasil oversee plantations laid out for easy access by specially trained and equipped workers. Tappers can manage as many as 10,000 trees apiece, versus only 1,500 or 2,000 in a traditional forest setting.
The trees themselves, bred for high productivity, yield four or five times as much gum as do natural trees, Morris says. Moreover, the trees grow rapidly and are ready for tapping after just seven years, instead of 15 years for standard trees. Once the trees are mature, they are cut for lumber. “They become a routine crop,” Morris says.
The tapping process, though, hasn’t changed much. Workers still cut a “face” on the tree a few feet off the ground and wait for the gum to run. They now collect it in plastic bags rather than wooden buckets.
In Patterson, Ga., a small company, Diamond G Forest Products, is seeking to revive the U.S. naval stores industry with a new tapping technique. Called borehole tapping, it was developed in the 1990s by Alan W. Hodges, a University of Florida scientist. The low-labor technique involves drilling small holes at the base of the tree, inserting a spout, and collecting the gum in bags.
Diamond G opened in 2012 to distill gum collected from company-owned land, according to R. D. Thomas Jr., a partner in the firm. “We have the only commercial distillery in the U.S.,” he says. The other partners are members of the Griner family, which distilled in the area until the 1960s.
Gum yields from the borehole method aren’t great—just a couple of pounds per tree per year versus up to 8 lb for the traditional method—but the product is easy to collect and very clean, Thomas says. Stimulants such as the plant growth regulator ethephon may boost output.
Cunningham, the consultant, agrees that the borehole method represents the future of the pine rosin business, but he says yields need to increase before it is widely adopted. Indeed, Cunningham is currently helping develop a pine rosin operation in Fiji that, at least at the start, will be based on traditional tapping.
Despite the pressures on the industry, Cunningham is optimistic about its future. Now that Chinese rosin output has fallen, some adhesive markets are switching to competing hydrocarbon resins, and rosin producers will pursue more demanding ink, food, and pharmaceutical applications. “Gum rosin will become more of a specialty chemical, not a commodity,” he predicts.
And don’t forget about the U.S., says Diamond G’s Thomas. “Can we bring the naval stores industry back to what it once was?” he asks. “No, can’t do that. But we can make it a viable industry in this country again. There’s no question about that.”
- Chemical & Engineering News
- ISSN 0009-2347
- Copyright © American Chemical Society