Lodgepole pine occupies 2.3 million acres in Idaho and grows under a wide range of conditions. It can be found in all the provinces except the Intermountain and Great Plains. It occurs in pure or mixed species stands. The amount of lodgepole pine cover type in Idaho has decreased slightly during recent decades. Fire, mountain pine beetle, and dwarf mistletoe are three important disturbance agents which greatly affect growth and development of lodgepole pine forests. The age of these forests on the whole are greater now than typically in the past, which has provided abundant food for mountain pine beetles.
Fire is a principal factor in the establishment and structure of most lodgepole pine forests. Historically, the frequency of fires varied every 60 to 500 years and their severity resulted in a diverse mosaic of age classes and species mixtures in Idaho’s lodgepole pine forest types.
In the Northern Rockies province, severe fires typically have created large expanses of even-aged, pure or mixed species stands of lodgepole pine. In the Southern Rockies Province, low-intensity surface fires often have maintained multi-aged stands in which climax species were unable to develop. The Middle Rockies have a good representation of both conditions. Fire suppression efforts, however, have reduced the diversity of age classes and forest structure.
Mountain pine beetle has played and continues to play an important role in the cycle of fire and reinvasion that has maintained lodgepole pine forests. By periodically killing trees and creating large amounts of fuel, the mountain pine beetle enhances the probability that a lodgepole pine stand will be destroyed by fire and will reoccupy the site before it is succeeded by other species. For example, between 1975 and 1981, millions of lodgepole pine were killed by mountain pine beetle in Idaho. After 20 years, most of those dead trees have fallen and created a “jackstraw” of woody material that represents a huge amount of fuel and a very high risk of fire.
There have been extensive logging activities in some parts of the state to salvage the dead trees and to harvest stands of lodgepole before they were attacked by the mountain pine beetle. This has created some areas of younger lodgepole forests, although the pattern of the forest patches is much different from what wildfires created in the past.
The occurrence and spread of dwarf mistletoe in lodgepole pine was limited in the past in some areas by large stand replacement fires. Fire suppression has allowed the amount of dwarf mistletoe in lodgepole pine to increase. In southern Idaho, an estimated 64 percent of all lodgepole pine stands contain some level of dwarf mistletoe infection.
The most common conifer in the northern Rocky Mountains, the lodgepole pine grows well in a variety of soil conditions and elevations. An opportunistic species, the lodgepole pine grows best in full sunlight, and quickly repopulates areas denuded by fires. Its bark is thin, making it susceptible itself to damage from surface fires. But because its cones release their seeds in the presence of heat, the lodgepole pine almost always regernerates following a fire, and crown fires that distroy vast areas often result in thick stands of lodgepole pines.
Lodgepole pines generally grow to about 70 feet in height, and to diameters of about 2 feet. It features stiff, dark bristles growing in groups of two, and 1- to 2-inch cones topped with stiff prickles. The bark of the lodgepole pine ranges from black to straw-colored, and is scaly in texture.
Once used by Native Americans for lodge and teepee supports, the hard, stiff wood of the lodgepole pine is today used in construction lumber, fencing, railroad ties, and house logs.