Overgrown sequoia forest, illustration. The giant sequoia (Sequoiadendron giganteum) is native to the Sierra Nevada mountains of California, USA. The thick bark makes the tree resistant to the recurrent forest fires of the region, which trigger the release of seeds from the sequoia cones. However, the increase in fire intensity in the 21st century has lead to more sequoias being killed in forest fires and their cones being incinerated. Overgrown forests with a dense underbrush of young trees and a build up of dry forest debris, as seen here, increase the intensity of forest fires. For a sequence of images showing the varying outcome of sequoia forest fires see C059/9893-9895.