The Economist reports on a trial of genetically modified chestnut trees:
Once upon a time, according to folklore, a squirrel could travel through America’s chestnut forests from Maine to Florida without ever touching the ground. The chestnut population of North America was reckoned then to have been about 4 billion trees. No longer. Axes and chainsaws must take a share of the blame. But the principal culprit is Cryphonectria parasitica, the fungus that causes chestnut blight. In the late 19th century, some infected saplings from Asia brought C. parasitica to North America. By 1950 the chestnut was little more than a memory in most parts of the continent.
American chestnuts may, however, be about to rise again — thanks to genetic engineering. This month three experimental patches will be planted, under the watchful eye of the Department of Agriculture, in Georgia, New York and Virginia. Along with their normal complements of genes, these trees have been fitted with a handful of others that researchers hope will protect them from the fungus.
The project has been organised by the Forest Health Initiative (FHI), a quango set up to look into the idea of using genetic engineering to rescue species of tree whose populations have been devastated by fungal diseases or insect pests. It has sponsored research at several universities, and this month’s trial is the first big field test. If it works, the FHI will ask the government for permission to plant transgenic chestnuts in the wild, with the intention of re-establishing the species in America’s woodlands. And if that goes well, it could provide a model for projects to re-establish elm trees (being devastated by Dutch elm disease, a beetle-born fungal infection), ash trees (threatened in North America by a beetle called the emerald ash borer, and in Europe by a fungal disease called ash dieback) and a fir tree known, confusingly, as the eastern hemlock (which is plagued by the woolly adelgid, a sap-sucking bug).