Whitebark pine is considered a “keystone species” in the mountain national parks, as it plays several important ecological roles where it exists in subalpine environments. Its survival has been threatened by the combined effects of fire suppression, climate change, mountain pine beetle outbreaks and a disease known as white pine blister rust. The 100-tree stand assessment protocol is a standard means of assessing blister rust infection rates in stands. This information is important because healthy trees in highly infected stands potentially have a higher likelihood of resistance. In these stands cones are collected from healthy, putatively blister rust-resistant trees. The information can also be used to prioritize which trees should be entered into rust screening trials. Blister rust and whitebark pine infection rates are calculated using this methodology and blister rust canker loads are determined.