Physiognomy and Structure: These forests and woodlands occur most frequently as dense, even-aged, early- to mid-successional stands, or less often as uneven-aged, later-successional stands where other conifers cannot become established. The understory varies from a conspicuous or sparse layer of shrubs or grasses to nearly barren substrate.

Floristics: Pinus contorta is the overwhelming canopy dominant often forming dense stands. Other conifers such as spruce and fir may become established. Populus tremuloides can occur as a seral component or in mixed stands with the lodgepole. The understory varies and may be conspicuous to absent and dominated by shrubs or graminoids. Common shrubs include Arctostaphylos uva-ursi, Arctostaphylos nevadensis, Artemisia tridentata, Juniperus communis, Ceanothus velutinus, Linnaea borealis, Mahonia repens, Purshia tridentata, Spiraea betulifolia, Spiraea douglasii, Shepherdia canadensis, Vaccinium scoparium, Vaccinium cespitosum, Vaccinium membranaceum, Menziesia ferruginea, Symphoricarpos albus, and Ribes spp. Common herbaceous species include Osmorhiza berteroi, Thalictrum occidentale, Thalictrum fendleri, Xerophyllum tenax, Clintonia uniflora, Carex inops ssp. inops, Arnica cordifolia, Festuca idahoensis, Elymus elymoides, Calamagrostis rubescens, Carex geyeri, Carex pensylvanica, and Carex rossii.

Dynamics:  Pinus contorta is an aggressively colonizing, shade-intolerant conifer which usually occurs in lower subalpine forests in the major ranges of the western United States. Establishment is episodic and linked to stand-replacing disturbances, primarily fire. The incidence of serotinous cones varies within and between varieties of Pinus contorta, being most prevalent in Rocky Mountain populations. Closed, serotinous cones appear to be strongly favored by fire, and allow rapid colonization of fire-cleared substrates (Burns and Honkala 1990a). Hoffman and Alexander (1980, 1983) report that in stands where Pinus contorta exhibits a multi-aged population structure, with regeneration occurring, there is typically a higher proportion of trees bearing nonserotinous cones. The dominance of Pinus contorta in associations in this group is related to fire history and topo-edaphic conditions (Pfister et al. 1977, Hoffman and Alexander 1980, Steele et al. 1981, Mauk and Henderson 1984). Following stand-replacing fires, Pinus contorta will rapidly colonize and develop into dense stands of even-aged trees. These stands, while frequently persistent for more than 100 years, may succeed to spruce-fir forests or woodlands. Most (but not all) forests in this group are early- to mid-successional forests which developed following fires.

Some Pinus contorta forest associations occur, and will persist, on sites that are too extreme for other conifers to establish. These include excessively well-drained pumice deposits (Volland 1976), glacial till and alluvium on valley floors where there is cold-air accumulation (Steele et al. 1981), warm and droughty shallow soils over fractured quartzite bedrock (Mauk and Henderson 1984), well-drained to xeric stabilized sand dunes (Jenny et al. 1969, Kumler 1969), and shallow moisture-deficient soils with a significant component of volcanic ash (Cooper et al. 1987). Some Pinus contorta forests can be persistent for hundreds of years, a result of a lack of seed source or the competitive exclusion of other conifer species (Moir 1969a, Pfister et al. 1977, Despain 1973b, Hoffman and Alexander 1983, Cooper et al. 1987), or the frost tolerance of Pinus contorta seedlings and mature trees, which allows the development of monotypic stands in frost-prone areas (Steele et al. 1981, Burns and Honkala 1990a).