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A moth species has killed off vast swaths of forest across Siberia, leaving so much dead, flammable wood behind that wildfires are now spreading faster than firefighters can
The trees that are burning across Krasnoyarsk this year were, in a lot of cases, already dead. Not from fire, and not from drought, but from a moth. Dendrolimus sibiricus, the Siberian silk moth, has spent the last several years stripping needles from fir, spruce, larch and pine across huge stretches of central Siberia, and a tree that loses its needles for enough consecutive seasons simply dies where it stands. It does not fall over. It does not decompose quickly in a climate this cold. It stays upright, drying out, for years, until something eventually sets it alight, and this year that something has been an unusually hot, dry stretch of Siberian summer. How a caterpillar kills a forest without ever touching fire The Siberian silk moth’s caterpillars are defoliators, meaning they eat needles rather than wood, bark or roots, and a single bad outbreak year can strip a stand bare across an area running into the hundreds of thousands of hectares. Research into the moth’s life cycle, published this year in Frontiers in Insect Science, examined why some populations follow a one-year larval cycle while others take two — and found the split isn’t simply a matter of temperature...