Beetle-killed and burned pine

Globs of resin on the outside bark of a pine tree indicate that it has been attacked by mountain pine beetles. The trees ooze this resin as a defense mechanism against the beetles. This pine tree has also been burned, probably in a forest fire.

Mountain pine beetle outbreaks can result in the loss of millions of pine trees throughout western North America. The beetles lay eggs and develop in the bark of mountain trees, especially lodgepole, ponderosa, Scotch, and limber pines. The beetles carry bluestain fungus spores, which infect the trees and turn the sapwood a bluish color. Both the beetles and the fungi eventually kill their host trees.