October 17, 2017—Footage from the wildfires in Sonoma County, California shows a tree in an odd way—a blaze glowing through narrow windows in the trunk. While driving to plan a possible evacuation route, Sonoma resident Matthew McDermott and a friend came upon the startling sight, and decided to take a closer look. What they saw, explains Scott Stephens, professor of fire science at UC Berkeley, is the end result of a fungus called Armillaria, that rots the core of trees. The material that remains within is dry, and cavities allow fire to penetrate to the tree's interior. The tree can burn for days, until eventually it can't support its weight, and collapses. Falling trees are one of the biggest causes of fatalities in wildfires.

October 17, 2017—Footage from the wildfires in Sonoma County, California shows a tree in an odd way—a blaze glowing through narrow windows in the trunk. While driving to plan a possible evacuation route, Sonoma resident Matthew McDermott and a friend came upon the startling sight, and decided to take a closer look. What they saw, explains Scott Stephens, professor of fire science at UC Berkeley, is the end result of a fungus called Armillaria, that rots the core of trees. The material that remains within is dry, and cavities allow fire to penetrate to the tree's interior. The tree can burn for days, until eventually it can't support its weight, and collapses. Falling trees are one of the biggest causes of fatalities in wildfires.