Seeing the forest for the trees
By Ildiko Kaszas

Transgenic poplar field.

OTTAWA — New controversy erupted in Argentina last December at the tenth anniversary of the United Nations conference on climate change. A flood of activists arrived to protest against genetically modified organisms. But this time, they'd set their sights on the world's forests.

Environmentalists denounced the UN's decision to include genetically modified (GM) trees in its Clean Development Mechanism. This allows member countries to use GM technology as a way of reaching carbon emission targets set out by the Kyoto Protocol.

During the conference, groups like the World Rainforest Movement and Friends of the Earth International released reports on the threats imposed by GM trees. And Anne Petermann, co-director of the US-based Global Justice Ecology Project, went so far as to say GM trees were antithetical to Kyoto.

“If these traits escape into native forests, which is virtually guaranteed,” said Petermann in a statement, “it will lead to the destruction and contamination of native forests, which will worsen global warming.”

Although Petermann’s claim may seem a bit far-fetched, fears that GM trees could irreparably damage the environment are not.

Forest biotechnology is still considered a relatively new area of research, but fields of transgenic poplars have already been planted in New Zealand and China – as well as Sweden and other European countries. As examples of scientific achievement, these experiments have attracted their fair share of criticism.

Dr. Sharon Regan in the greenhouse.

In Canada, where GM science proceeds at a more cautious rate, the story is surprisingly different.

“Those are the exception to the rule,” says Dr. Sharon Regan, a biology professor at Queen’s University in Kingston. “You don’t see plantations of GM trees for commercial purposes anywhere else but there [New Zealand and China]."

Regan is one of five scientists taking part in a Genome Canada project on GM poplars. The study aims to help forestry researchers better understand the basic biology behind trees.

The study focuses exclusively on that species, says Regan, because the poplar genome has already been sequenced. Poplars also adapt well to small spaces and can be cut back if they grow too tall. But with a potential sample size of thousands, Reagan’s greenhouse laboratory is still cramped. The full sample — between five and seven thousand trees — will be planted by September 2005.

Each tree sample is engineered with some type of alteration using tissue cultures at the single-cell stage. Regan uses a section of DNA from a particular virus to ‘turn on’ genes in each plant. This DNA strand is inserted into the poplar cells, which are then left to grow in a greenhouse. 'Activation tagging,' as it's known, helps scientists track the function of an individual gene. But they have no way of predicting where the virus ends up.

Small transgenic plants.

“We don’t know where we’re going to see an effect,” says Regan. “Is it going to be in the root or the stem or the leaf? It’s really a blind experiment. We really have no idea what we’re looking for.”

The entire process, from single cell to a hand-sized sapling, takes about a year.

Once the poplars have grown enough, researchers look for any changes that result from the altered gene. Theoretically, each sample would contain an activated gene that’s different from the rest, says Regan. Once scientists have identified an interesting trait, they can compare the lab's samples to natural populations. This would help them locate trees with a specific gene ‘turned on’ at a high level. Regan says those in the forestry industry could eventually come in and screen these samples for desired traits.

“We can develop a diagnostic kit to help find superior trees that are already out there.”

For Regan, this test would be an addition to traditional breeding techniques — not a replacement. As for genetically modifying trees for commercial purposes, Regan says it won’t be necessary.

“In agriculture, genetically modified foods will be necessary because we have lost a lot of that genetic information over thousands of years of breeding. In forestry, there’s a huge diversity already out there.”

She illustrates her point by describing the common potato:

In the process, says Regan, the potato has lost a lot of other genes. After centuries of breeding, crops have become very susceptible to disease. The difference in forestry, she says, is that trees have only been bred for the past 50 years. The potential still exists that trees can have the same disease-resistant genes they had 10,000 years ago.

Across the border at Environmental Defense, Rebecca Goldberg points to other examples of genetic modification gone wrong. Goldberg says that because most crops harvested today originated from abroad, they don’t have natural variants to interbreed with. Trees that are cultivated for pulp and paper, on the other hand, have wild relatives that promote genetic diversity. And unlike crops, trees take a much longer time to reach maturity.

“With croplands, they’re typically just grown for one year and removed, and so if there’s evidence of a problem, at least the crops aren’t grown all the time. With trees, you plant them, they stay in the ground for decades, they may flower numerous times, so there’s more opportunity for gene flow to wild relatives.”

Goldberg says the potential to engineer sterility does exist, but natural selection favours the restoration of fertile traits.

“If you know anything about evolution, that makes sense,” says Goldberg. “Sterility might work on a short timescale to enable an experiment, but the notion that one could engineer trees to be sterile over thousands and millions of acres over a lifespan of trees and have them all stay sterile just doesn’t seem very realistic.”

Even if trees are engineered fairly quickly, she says, it takes a while to see what the effects are.

“Once you put in genetically engineered trees on a large scale, if something goes wrong, the economic cost of ripping them out is enormous,” says Goldberg. “It may be hard, politically, to reverse even an acknowledged mistake.”

Dr. Armand Séguin and his team at the Laurentian Forestry Service are dealing with these issues first-hand. On a plantation in Northern Québec, Séguin is conducting the first ever field trial of transgenic poplars in Canada.

The study is being closely monitored by the Canadian Food Inspection Agency, the regulatory body responsible for all GM testing. Although the poplars being used in the trial are sterile, they are still monitored for signs of flowering and pollination on a regular basis. Because pollen can travel over great distances, the prospect of contaminating native forests is a particularly worrisome threat.

“We have to climb on ladders and look through binoculars to see their tops and check for flowering because the poplars grow so fast,” says Séguin.

And even after the trees are cut down, the CFIA insists that the stumps are completely uprooted and destroyed. Séguin calls this process ‘restrictive.’ But like Regan, Séguin says his main goal is simply to better understand trees.

The poplars used in Séguin’s field trial each contain two marker genes . These markers check to see whether genetic transformation has taken place. They also monitor for genes that may end up in the soil through leaf and branch decomposition. Séguin says the persistence of genetic information should not be a concern.

“When you eat beef, you eat beef DNA. When you eat salad, you eat salad DNA. It doesn’t mean you take on those traits.”

Séguin says there’s no way to guarantee that genes from GM trees will not be transferred into native forests. But he says that cross breeding and genetic modification happens all the time in nature..

“If a gene doesn’t have a specific advantage, then it’s diluted in the environment,” says Séguin. “There’s no current research to suggest that GM trees are any more harmful than regular trees to humans or the environment.”

For Séguin, it boils down to a fear of the unknown. He says field trials of GM trees are necessary because “we’re already in the red.” New pests are always one step ahead of modern technology and destroying our forests. If we didn’t have a problem, says Séguin, then there would be no need for genetic modification.

When it comes to pest management, Regan agrees.

“We have two choices,” she says. “Either lose the tree completely and just never grow it again, or introduce a tree — the same kind that has a genetic modification that gives it resistance to that bug.”

But for Goldberg, the answer is not so straightforward. GM trees aren’t necessarily the answer to the demands put on natural forests. If scientists engineer trees to be resistant to certain pests, she says, they may be also depriving other species of food. The potential effects need to be viewed both up and down the food chain.

As for commercial tree plantations — like those currently found in New Zealand and China — the reviews are mixed.

“Producing more wood on tree farms isn’t necessarily a bad thing, if you can make the tree farms more productive,” says Goldberg. “But there also are questions about doing the farming in a way that’s ecologically sound. One has to consider all the tradeoffs. It’s one thing for some tree plantation to put in a more domesticated, genetically engineered tree that’s safe. It’s another if the forest service starts planting them on land that’s used for conservation purposes.”

Regan says it’s likely trees will be genetically engineered with very special chemical properties so their wood can be used by different industrial sectors.

“Really, the sky’s the limit on what kind of changes could be put onto those [trees] that could meet so many demands in other areas,” says Regan. This could include better thread for surgery, parts for electronics and improved wood materials, like rayon. “It’s kind of like designer wood,” she says.

In Regan’s greenhouse, the poplars are already showing radical differences in appearance — some plants developed leaves with jagged edges, while others maintained the smooth, flat leaves common in poplars. Regan says she’s spotted at least 10 unusual plants, but expects that number to increase when screening begins.

“It’s exciting, it means the whole technology is working,” she says. “The strategy works.”

The potential benefits of GM research are enormous: better wood for the pulp and paper industry, and resistance to alien pests and bioremediation --removing metals from infertile soil. And Canada is one of the few countries left in the world with its natural forests still intact.

“We’re in a relatively unique opportunity to preserve those [natural forests], and so a lot of the push — both from scientists and the industry — is to change our forestry practice, move it away from taking trees from natural forests and instead move to plantation forestry,” says Regan. But these plantations would still consist of natural trees and not ones that are genetically modified.

Regan’s team plans to monitor the poplars for the next 10-15 years. The trees will have to be followed over the long term, she says, because certain traits may not show up for several years. Regan says she expects to get the most out of her study by analyzing the poplars repeatedly over the next two decades.

And that’s about how long it would take before GM trees would be seen on the open market. According to Séguin, they won’t become commercially viable for at least another 10 or 15 years. Until then, both scientists and policy makers will have to take the process one step at a time. Séguin says the trick is to find a balance between the unknown risks of genetic modification, and the more obvious risk of doing nothing.

“Reforestation with GM trees is like money you gain and then lose, not like money that’s already been stolen.”