As written in a guide to the Calaveras Big Trees State Park, "Sierra redwoods evolved in the presence of fire, and not only have adapted to it, but depend on it in several ways. Heat from fire causes the cones to open and release the seeds. Fire clears the ground of duff, litter, and brush so the tiny seeds can reach the mineral soil and receive plenty of sunshine. ... The opening (in the Pioneer Cabin tree) has reduced the ability of the tree to resist fire. A few branches bearing green foliage tell us that this tree is still managing to survive."