At timberline, they grow under conditions tolerated by no other tree species, thus playing an important role in snow accumulation and persistence. Because few roads occur in whitebark pine ecosystems and because the tree's wood is of little commercial interest, information on the drastic decline of this picturesque tree has only recently emerged. Mortality level is the proportion of trees dead from all causes since presettlement.
Blister rust is present but infection rates are unknown in Canada and the southern United States.
Threats Fig. 2. Healthy whitebark pine stand in Yellowstone National Park not yet affected by the introduced disease, white pine blister rust. Reinhart Whitebark pine is threatened by an introduced disease and fire suppression. Fewer than one whitebark pine tree in 10,000 is rust-resistant. Dead whitebark pine trees in Glacier National Park.