Rocky Mountain Lodgepole Pine
Pinus contorta Dougl. ex Loud

The Rocky Mountain Lodgepole pine was among the trees discovered by Lewis and
Clark on the Lemhi River on 13 Aug 1805. 

Rocky Mountain Lodgepole pine is a small- to medium-sized, coniferous, evergreen tree. Mature tree heights range from 50 to 100 feet (15-30 m) and bole diameters occasionally reach 24 inches. Mature size varies regionally. The trees are short-lived. Two-hundred-year-old trees are rare, except around Yellowstone National Park, where pure stands contain 300- to 400-year-old trees.  Rocky Mountain Lodgepole pine has sharp-pointed, 1- to 3-inch-long, yellowish-green needles in fascicles of two. The bark is thin (less than 0.5 inch, light-colored, and scaly, except for low-elevation plants in northern Idaho and southern British Columbia which may have thicker, deeply fissured, black bark. The root system is highly variable, and may vary among individuals at a single location from very shallow to quite deep . Individual trees may have serotinous or nonserotinous cones. 

Rocky Mountain Lodgepole pine grows across a wide range of environments in montane and subalpine forests of the West. With a broad range of moisture and temperature tolerances, it occupies forests spanning a range of environmental conditions from relatively low-elevation, warm and dry forests to relatively high-elevation, cold and moist forests. It grows at elevations form 4,000 to 11,000 feet. Lodgepole pine grows on a wide variety soils but grows best on moist, medium-textured soils derived from granite, shale, or coarse-grained lava parent materials. It rarely grows on soils derived from limestone, except in Canada, where extensive stands occur on calcareous glacial tills. It is often the only tree that grows on very infertile soils. (Source)