This ecological system is widespread but patchy in distribution in upper montane to subalpine zones of the Montana Rocky Mountains, and east into mountain island ranges of central Montana. These are upper montane to subalpine forests where the dominance of lodgepole pine (Pinus contorta)is related to fire history, topo-edaphic conditions and nutrient-poor soils. Presence of this system is determined more by substrate than by other factors. The most notable occurrence of this system is in the West Yellowstone Basin and surrounding Yellowstone Highlands, such as the Madison Plateau. In this region of Montana, cold-air ponding and coarse, rhyolitic outwash obsidian sands are the major factors contributing to the extensive development of this system in southwestern Montana. Fire is infrequent in this system, averaging every 150-400 years in subalpine forests. Following stand-replacing fires, lodgepole pine will colonize rapidly on sites that are too extreme for the establishment of other coniferous species, developing into dense, persistent, even-aged stands. Mature stands are primarily open, and develop past their initial even-aged structure to become a multi-aged structure. These stands last for longer intervals between disturbances than do conventional lodgepole pine-dominated stands.
forest and woodland, acidic, very shallow ustic soils, organic A horizon less than 10 cm, Pinus contorta
These forests are dominated by lodgepole pine (Pinus contorta) withsparse undergrowth. At the closed canopy stage of stand development, undergrowth may be totally lacking. Some open stands with very sparse understories can experience a form of mixed-severity burning along downed logs when there are insufficient fuels between logs to carry fire. Depending on the arrangement and loading of logs to living trees, either mortality or fire-scarring may occur.
The shrub layer may be conspicuous to absent. Common species include bearberry (Arctostaphylos uva-ursi), snowbrush ceanothus (Ceanothus velutinus), twinflower (Linnaea borealis), creeping Oregon grape (Mahonia repens), antelope bitterbrush(Purshia tridentata), birch leaf spiraea (Spiraea betulifolia), Canadian buffaloberry (Shepherdia canadensis), dwarf huckleberry (Vaccinium caespitosum), grouse whortleberry (Vaccinium scoparium), snowberry (Symphoricarpos species) and currant (Ribesspecies).
Herbaceous layers are generally sparse, but can be moderately dense, and are typically dominated by perennial graminoids such as Columbia needlegrass (Achnatherum nelsonii), pinegrass (Calamagrostis rubescens), Geyer’s sedge (Carex geyeri), Ross’ sedge (Carex rossii), bottlebrush squirrel tail (Elymus elymoides), California oatgrass (Danthonia californica), blue wildrye (Elymus glaucus), and Idaho fescue (Festuca idahoensis). Common forbs include yarrow (Achillea millefolium), arnica (Arnica spp.), silky lupine (Lupinus sericeus), phlox (Phlox spp.), buckwheat (Eriogonum spp.), and beargrass (Xerophyllum tenax).
Restoration strategies will depend largely on fire severity. Under favorable moisture conditions, seeds released from serotinous cones during the fire germinate on exposed mineral soil and disturbed duff the following spring. Fire creates a favorable seedbed by removing loose organic matter and exposing mineral soil or decomposed organic matter, which encourages germination. Thus, in light or moderately severe fires, additional restoration practices are not required. Early successional stages following fire in lodgepole pine forests are dominated by an undergrowth of forbs and to a lesser extent graminoids such as fireweed (Chamerion angustifolium), aster (Aster species), nettleleaf giant hyssop (Agastache urticifolia), and pinegrass (Calamagrostis rubescens).
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