abstract:The Subalpine Fir or Rocky Mountain Fir (Abies lasiocarpa) is a western North American fir, native to the mountains of Yukon, British Columbia and western Alberta in Canada; southeastern Alaska, Washington, Oregon, Idaho, western Montana, Wyoming, Utah, Colorado, New Mexico, Arizona, northeastern Nevada, and the Trinity Alps in northwestern California in the United States. It occurs at high altitudes, from 300–900 m in the north of the range (rarely down to sea level in the far north), to 2,400-3,650 m in the south of the range; it is commonly found at and immediately below the tree line.