Pinus flexilis, the Limber pine, is a keystone species here in Rocky Mountain National Park. It is also known as Rocky Mountain white pine. Limber pine were named for the extremely flexible branches on younger trees. Notable characteristics include the flexible branches and a grey smooth bark on young trees, while mature trees the bark is dark brown, thick with scaly ridges. Cones are around 6 inches in height, needles are 2-3 inches long in fascicles of 5 typically. While learning to identify this type of pine tree I was able to note the distinguishable characteristics between other species such as Pinus ponderosa and Pinus contorta (Lodgepole Pine).
The purpose in identifying Pinus flexilis was to investigate a fungal outbreak of Cronartium ribicola, which is a white pine blister rust. The hope was to reduce spreading the infection between trees and support a healthy Limber pine population in the park. I am hopeful the infected pine trees will recover to continue growing strong and healthy along the mountains.