This is a new window. To return to previous page, simply close this window.
GENETICS & APPLIED ECOLOGY
DNA: Code of the Wild
The Topic In-Depth #2: Forestry Genetics
by Sally Lehrman
March 2002
While the public debates the merits of biotech corn, soybeans and papaya already in the US food supply, genetic science is lurching toward a new agronomic frontier - forest trees.
Foresters envision high-intensity pine and poplar plantations quick to grow and cut, with the natural forest left unharvested. Some would like to bring back heritage trees such as the American chestnut, long ago nearly choked to extinction by a fungus introduced from Asia. Others dream of hardy trees planted along hazardous waste sites, sucking toxins out of the soil with their roots.
But for now, fears about ecological safety and public acceptance may restrict gene alteration mostly to the greenhouse.
Paper and wood products companies, troubled by vandalism and business issues, have cut back investment in transgenic research. Most academic scientists recognize that even the most well-intentioned genetic tinkering is bound to collide with the spiritual and symbolic stature of natural forests, which have long been both sacred and scary to humans. Many also worry about long-term ecological risk that can't yet be measured.
"The impact on ecology is really unknown. My personal feeling is I want to know the ecology before doing genetic engineering," says Hou-Min Chang, a wood chemist at North Carolina State University who is using molecular techniques for breeding trees. "It's one thing to take what Mother Nature has given us, and it's another to mess with Mother Nature."
For the time being, many researchers say they prefer to use DNA alteration as one tool among many. The most socially acceptable transgenic projects will likely progress first, they predict, then others will follow.
"That's okay with me," says William Powell, who has met scant criticism for trying to engineer the American chestnut to resist its attacker. "We're generating a lot of data that will help others."
Forest researchers also tend to downplay any transgenic aspects of their work for fear of attacks on their laboratories and outdoor plots. Activists have ripped out plantings and, in May 2001, firebombed a University of Washington building that housed a poplar genetics research cooperative. The Earth Liberation Front, which says it targets those who profit from destroying and exploiting the natural environment, claimed responsibility for the fire.
Paper and wood products companies, already cautious because of regulatory hurdles and patenting uncertainties, also are keeping a low profile, says Steven Strauss, a forester and molecular biologist at Oregon State University. While executives are investing in research to improve trees for commercial purposes, they have stopped short of committing to transgenics for future forests.
Nevertheless, a consortium including International Paper, Fletcher Challenge Forests and Westvaco Corp. has invested $60 million in biotech trees and a variety of others, including Weyerhaeuser, Potlatch, and Alberta Pacific, also are supporting research.
Strauss worked with industry for nearly a decade to develop transgenic poplars with the same properties as some genetically engineered food crops. Some can withstand Monsanto's weed-killer, Roundup, and others make a toxin borrowed from the bacterium, Bacillus thuringiensis, to protect them from insects.
"These traits really do deliver the phenotype and produce great trees," he says. But Strauss adds that he's phasing out the program now that his group has proved the concept works. Now he companies must decide whether to pursue the technology on their own, he says.
"Commercial interest isn't real strong because of terrorism and the hype demonizing all of biotechnology," Strauss says. In the spring of 2001, vandals hit one of Strauss' government- and corporate-funded plots, damaging or killing 960 young transgenic and control trees being used for research. "It's a big cost and it's a stigma thing," he says.
Now Strauss is working on ways to interrupt the flowering process. Non-flowering trees are expected to grow faster, making them more useful commercially. They'll ease problems with allergens and fruiting in urban trees. Plus they'll make it harder for gene alterations to leak into the wild through pollen and seeds.
Some activists say tree manipulation is so dangerous it should only occur under the strictest conditions of containment. They cite consequences to the environment that may only show up years later. Such repercussions may include harm to insects, animal life and other forest species. Strauss insists that planting transgenic trees outdoors will be the only way to truly understand their genome, since plants grow differently there than in a greenhouse. He says suggestions to put a moratorium on forest genetic engineering are foolish.
"That's just dumb, because you're foreclosing options; you're applying a broadband stigma. We have to have a place where we can learn about (trees) really well," he says.
In about 18 months, when forestry molecular biologists expect to know the full poplar genome, "that's going to change everyone's life," Strauss says. Suddenly researchers will be able to test ideas they had ignored because they would take ten years of study. Foresters will be able to compare poplar genes with other plants to guess their function, then quickly check how the tree manages flowering, its response to stress and other important processes.
The US Department of Agriculture doesn't keep track of the total number of forestry field trials it has approved, according to a spokesman. But Faith Campbell, who directs the program on transgenic trees for the conservation group American Lands Alliance, counted up and confirmed those listed on public databases, identifying on the order of 60 transgenic field trials okayed by the agency as of January 2002.. Some scientists would like to move a little more slowly.
"Use the standard scientific method instead of operational plausibility," says Daniel Botkin, an ecologist at the University of California in Santa Barbara. He emphasizes that natural ecosystems have complicated rules that scientists don't fully understand. "You should proceed quite cautiously because nature doesn't play fair," Botkin says. "We're always trying to do what we think are simple things and finding that they have indirect effects."
At least one study at Oregon State University has found that genes do flow out from genetically engineered hybrid poplar stands into wild trees, although at low rates. Engineered trees and their kin could become super trees, some scientists worry, invading and disrupting forests like kudzu, an aggressive Japanese vine that has overwhelmed seven million acres in the Southeast.
Botkin also suggests that altered trees and widespread plantations might change the wild forest and even broader ecosystems in unforeseen ways. Whole forests affect the regional climate through reflecting light, evaporating water, exchanging greenhouse gases and influencing wind. Individual trees interact with the soil and surrounding plant and animal communities; a toxin engineered into a tree to protect it against a fungus, say, might leak into the ground through roots and decaying leaves and kill beneficial organisms.
Botkin makes the case that improved forestry practices on more plantations could ensure the world's wood and paper supply much more quickly and safely than genetic engineering. Already, corporations in some areas grow trees for lumber and paper as if they were rows of broccoli. In northwestern Oregon, 40,000 acres of poplar trees fed by drip irrigation are bound for wood frames, molding, veneer and plywood. Across the southeastern US, much of the forest is actually small loblolly wood lots grown on land that used to be agricultural plots for tobacco and other crops.
Botkin says that he thinks some gene manipulation may make sense, but any sort of forestry engineering should involve small-scale studies with carefully monitored trees that are unable to reproduce. He points to the chestnut project as an appropriate use of genetic engineering, since the goal is to bring back an endangered species. But the tree still could upset forest ecology by out-crossing with other types of trees or, if the new gene creates a toxin in the chestnuts, harming deer that rely on them for food.
"I'm a scientist and I like science," Botkin emphasizes, but adds that scientists have often harmed the environment despite their best intentions. "We have a long history of scientists not understanding the ecosystem effects or the social and cultural consequences of what they're doing," he says.
"We're not near to optimal use of plantations, and that poses no risk. Why go the untested route of fancy genetic engineering that carries unknown risk?"
Additional original articles on genetics and applied ecology:
|
