Eucalyptus Trees May Improve U.S. Forest Production

Published March 8, 2010

A joint venture between two paper companies is testing the feasibility of introducing genetically modified eucalyptus trees as a new staple crop in the U.S. Southeast. Initial test results are promising, though some environmental groups claim genetically modified eucalyptus trees could squeeze out native trees.

Faster Growth
Eucalyptus trees, which are native to Australia, grow much more quickly and produce more wood per acre than the pine trees that dominate forestry and paper production in the U.S. Southeast.

Eucalyptus trees can grow to 55 feet tall in a matter of only 27 months, and they sequester atmospheric carbon far more rapidly than pine trees. Nations that have imported eucalyptus trees have experienced substantial growth in forestry production, with Brazil, for example, transforming itself from a net wood importer to a net wood exporter.

As a tropical species, eucalyptus trees are susceptible to cold weather, and experimental plantings in the Southeastern U.S. have failed everywhere except Florida. Genetic modifications have recently been developed, however, that enable eucalyptus trees to be somewhat freeze-tolerant.

Preventing Expansion
Forestry companies are seeking to alleviate environmentalists’ fears of genetically modified eucalyptus trees expanding beyond commercial forestry sites and taking over native pine forests, by introducing a bacterial gene that kills eucalyptus pollen cells. The inability of the trees to maintain healthy pollen cells would make it extremely difficult for them to expand into new territory.

ArborGen, a joint venture between International Paper Co. and MeadWestvaco Corp., reports successful results in initial field trials. Eucalyptus trees modified with the pollen-killing bacterial gene have been unable to produce pollen at ArborGen testing sites.

As a next step, ArborGen is seeking U.S. Department of Agriculture permission to allow genetically modified trees at 28 testing sites to produce full flowers. To date, ArborGen has been required to pluck flowers from the trees as soon as the flowers emerge.

Benefits Outweigh Small Risks
Henry I. Miller, research fellow at the Hoover Institution, said genetically modified eucalyptus trees offer many benefits and few risks.

“These new varieties of eucalyptus trees are yet another ingenious application of state-of-the-art biotechnology to agriculture. They illustrate how commerce and environmental considerations are symbiotic,” said Miller. “These new tree varieties are so adept at sequestering atmospheric carbon, yet pose negligible risks to the natural environment.”

Steve Strauss, distinguished professor at the Oregon State University Department of Forest Ecosystems and Society, agreed.

“You don’t want to have all your eggs in a single basket regarding forestry and potential biofuels production,” said Strauss. “Eucalyptus trees would be a nice addition to the forestry mix in the Southeast. They have a very high growth rate, they are drought tolerant, and they have very different properties than pine trees.”

Strauss does not believe the trees are likely to become a nuisance species.

“I don’t think we can rule out the possibility of genetically modified eucalyptus trees becoming an invasive species, but from what we know now, the threat looks very small and manageable. In Brazil – a warm, moist environment like the U.S. Southeast – they have imported and grown eucalyptus trees on a huge scale, yet it hasn’t been an aggressive species. It has hardly spread at all,” Strauss explained. “In places like South Africa, where drier weather is more conducive to eucalyptus trees, they have still been able to manage the spread of these trees. Just because you have spread, it doesn’t mean you can’t manage it.”

Strauss advocated continued testing of the genetically modified trees, on a larger scale.

“It would be a pity to put this exciting new technology on the shelf over small, hypothetical risks,” said Strauss. “The male sterility system appears to be working very, very well. They are also working on female sterility system which is also promising. It doesn’t look like spreading will be an issue, but if it becomes an issue, there are many options to contain it.”

“If you had a cold-tolerant species of eucalyptus that was not genetically modified, you would be able to plant it without restrictions, and nobody would demand such restrictions. Simply because these trees have been genetically modified, all sorts of restrictions and different rules apply. It would be a shame if the genetic modification of this tree keeps it from contributing to our forestry mix.”

Krystle Russin ([email protected]) writes from Texas.