Demystifying science | Genetically modified trees against fires

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Is it possible to genetically create a species of trees that would not, or almost not, burn in a forest fire?
—Jean Pellerin

Yes. But these are trees genetically modified to be less vulnerable to insects.

“If the tree is healthier, it will be more resistant to fire,” explains Armand Séguin, biologist with the Canadian Forest Service (CFS). “The leafroller has defoliated many conifers in Canada. Additionally, dead needles on the ground are very flammable. »

Mr. Séguin carried out one of the only tests in Canada of transgenic trees, 20 years ago in Canada. These were spruce trees which contained a gene expressing the bacteria Bacillus thurigiensis (Bt), which has pesticidal properties, protecting in particular against the leafroller. Many transgenic agricultural seeds have this Bt gene.

“We did this in a closed area, to see if there was an impact on the composition of the soil,” says Mr. Séguin. It was a success: the trees were more resistant to insects, they expressed Bt, and there was no significant effect on the ecosystem. But public discourse on transgenic trees has taken a negative direction. So there was never any follow-up to this research. »

The test was carried out near Valcartier, in land used for closed SCF tests. It ended in 2007 with the destruction of all genetically modified (GM) spruce trees. Previously, Mr. Séguin had demonstrated that it was possible to have GM trees with poplars and a harmless bacteria. Subsequently, he carried out a test of GM poplars aimed at the production of bioethanol.

Eucalyptus

Would it be possible to have GM trees resistant to fire in other ways?

“But it is difficult to increase the quantity of lignin, which gives wood its hardness, because it depends on many genes,” he adds.

Research has taken place with the opposite objective: to reduce the quantity of lignin in hardwoods, to promote paper production. “We saw that there is a metabolic cost for the tree to produce more lignin, so we can wonder if these GM trees would grow quickly enough. »

Shrubs that grow quickly, like eucalyptus, have less lignin and more water. But it would also be difficult to have GM trees with more water, again because it is a trait that depends on several genes.

A committee of the Forest Stewardship Council, a German NGO which certifies “sustainable” forests, looked a few years ago at the relevance of accepting GM trees. “I was approached to be part of the committee, but I didn’t have the time,” said Mr. Séguin. Ultimately, the discussions were abandoned. If there is no market, no certification possible, there will be no commercial development. It’s a shame, because the Bt gene is natural. GM trees are natural,” he insists, even if his opinion does not achieve consensus in society.

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