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Montana Field Guides

Rocky Mountain Poor Site Lodgepole Pine Forest

Provisional State Rank: S3

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General Description

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.


Diagnostic Characteristics

Forest and woodland, acidic, very shallow ustic soils, organic A horizon less than 10 cm, Pinus contorta


Similar Systems

Range
This system occurs in parts of the upper montane and subalpine elevations throughout the Montana Rocky Mountains. Elevation ranges from 975 to 2,743 meters (3,200-9,000 feet). Presence of this system is determined more by substrate than by other factors. In north-central Montana, it can be found on appropriate habitats with intrusive volcanics and very nutrient-poor soils within the Little Rocky Mountains near Zortman and the Big Snowy and Highwood island mountain ranges. The most extensive Montana expression of this system is the West Yellowstone Basin and the 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 its extensive development.

Ecological System Distribution
Approximately 94 square kilometers are classified as Rocky Mountain Poor Site Lodgepole Pine Forest in the 2016 Montana Land Cover layers.  Grid on map is based on USGS 7.5 minute quadrangle map boundaries.



Montana Counties of Occurrence
Beaverhead, Blaine, Carbon, Cascade, Chouteau, Deer Lodge, Fergus, Flathead, Gallatin, Granite, Hill, Judith Basin, Lewis and Clark, Madison, Meagher, Missoula, Park, Phillips, Pondera, Powell, Ravalli, Sweet Grass, Teton

Spatial Pattern
Large patch

Environment
This system generally occurs on dry to intermediate sites with a wide seasonal temperature range and long precipitation-free periods in summer. Snowfall is heavy and supplies the major source of soil water used for growth in early summer. The nutrient-poor soils include excessively well-drained pumice deposits; glacial till and alluvium on valley floors where there is cold air accumulation; warm and droughty shallow soils over fractured quartzite bedrock; and shallow moisture-deficient soils with a significant component of volcanic ash. Soils supporting these forests are typically well-drained, gravelly, coarse-textured, acidic, and rarely formed from calcareous parent materials.

Vegetation

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).


National Vegetation Classification Switch to Full NVC View

Adapted from US National Vegetation Classification

A3207 Artemisia tridentata ssp. spiciformis - Artemisia tridentata ssp. Vaseyana Steppe & Shrubland Alliance
A3366 Pinus contorta Rocky Mountain Forest Alliance
CEGL000134 Pinus contorta - Arctostaphylos uva-ursi Forest
CEGL000139 Pinus contorta - Calamagrostis rubescens Forest
CEGL000141 Pinus contorta - Carex geyeri Forest
CEGL000144 Pinus contorta - Carex rossii Forest
CEGL000172 Pinus contorta - Vaccinium scoparium Forest
A4079 Pinus contorta Rocky Mountain Woodland Alliance
CEGL000764 Pinus contorta - Juniperus communis Woodland
CEGL000765 Pinus contorta - Purshia tridentata Woodland
*Disclaimer: Alliances and Associations have not yet been finalized in the National Vegetation Classification (NVC) standard.  A complete version of the NVC for Montana can be found here.

Dynamic Processes

Establishment of lodgepole pine in this system is episodic and linked to stand-replacing fire. Lodgepole pine forests with very sparse understories experience longer fire return intervals ranging from 120 to over 300 years in comparison to stands with more productive understories (U.S. Department of Agriculture, 2012). This ecosystem also experiences a greater percentage of fires of mixed severity, with fewer stand-replacing fires than more productive lodgepole forests (USDA, 2012). Longer fire return intervals and decreased fire severity is largely attributable to the absence of significant ladder fuels in this system (Anderson, 2003). Fuel loading in this system is primarily a result of downed woody debris from past disturbances (e.g. mountain pine beetle, windfall), and sparse understory is not effective at sustaining high-intensity fires (Agee, 1996; Smith and Fischer, 1997). Fire severity is therefore only great as a result of long-term fuel accumulation, or severe climate conditions (Agee, 1996; Smith and Fischer, 1997).

Biotic disturbance agents also influence stand susceptibility to fire, and in general, vulnerability to biotic vectors increases with stand age and density. Lodgepole pine dwarf mistletoe (Arceuthobium americanum) increases host susceptibility to fire by altering fuel dynamics and increasing crown fire potential, and intensifies host vulnerability to insect attack (Hawksworth et al., 2002). Rocky Mountain lodgepole pine stands have historically experienced chronic infestations of mountain pine beetles (Dendroctonus ponderosae). Mountain pine beetles preferentially attack large individuals with greater nutritional resources, although elevated temperatures and increasing drought severity additionally combine to favor beetle population growth and weaken lodgepole pine defense mechanisms, increasing incidence of large-scale outbreaks (Raffa et al., 2008).

Dense, even-aged stands resulting from stand-replacing fires are increasingly susceptible to windthrow and snow damage as they mature (Smith and Fischer, 1997). Individual trees that have matured in dense stands obtain a degree of protection from neighboring trees, such that the development of deep roots and other physical mechanisms to withstand wind exposure are unnecessary. Additionally, the shallow soils typical of this system contribute to the development of shallow rooting systems. As a result, increased wind exposure resulting from natural or mechanical thinning amplifies susceptibility to windfall (Anderson, 2003).

Trees with closed, serotinous cones appear to be strongly favored by stand-replacing fire, and allow rapid colonization of fire-cleared substrates (Burns and Honkala, 1990). These forests often exhibit a multi-aged population structure, with non-fire regeneration, and often exhibit a higher proportion of trees bearing non-serotinous cones. Additionally, the mixed-severity fires and generally longer fire return intervals characteristic of this system favor regeneration from non-serotinous cones (Anderson, 2003; Schoenagel et al., 2003). If serotiny is expressed in these stands, cone polymorphism exists and allows regeneration after non-fire disturbance.


Management
Effects of fire, fire suppression, fuel accumulation, stand development, insects, and disease in these forests interact to control the establishment and maintenance of stands. In the absence of natural fire, periodic prescribed late season burns can be used to maintain this system and increase productivity by opening the stand and encouraging regeneration (Smith and Fischer, 1997). Periodic burning is particularly important to avoid stagnation or succession by shade-tolerant species in even-aged mature stands exhibiting serotinous cones. Low-severity prescribed burning may be limited by a lack of surface fuels and should be administered in late fall when fine fuels have dried (Anderson, 2003).

Restoration Considerations
Restoration strategies will depend largely on management goals. In stands where fire exclusion has occurred, restoration of historic fire regimes can decrease stand susceptibility to future mountain pine beetle attack, and prescribed burning can be used to control dwarf mistletoe if infected individuals are eliminated (Anderson, 2003; Hawksworth et al., 2002). Under favorable moisture conditions, seeds released from serotinous cones during 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. Natural regeneration may, however, be marginal when stand-replacing fires are followed by years of severe drought (Stephens et al., 2013), and may require supplemental restoration efforts. In scenarios that necessitate supplementary planting, germination rates for seeds from serotinous cones may be enhanced by short exposure to flame (Anderson, 2003).

Species Associated with this Ecological System
  • Details on Creation and Suggested Uses and Limitations
    How Associations Were Made
    We associated the use and habitat quality (common or occasional) of each of the 82 ecological systems mapped in Montana for vertebrate animal species that regularly breed, overwinter, or migrate through the state by:
    1. Using personal observations and reviewing literature that summarize the breeding, overwintering, or migratory habitat requirements of each species (Dobkin 1992, Hart et al. 1998, Hutto and Young 1999, Maxell 2000, Foresman 2012, Adams 2003, and Werner et al. 2004);
    2. Evaluating structural characteristics and distribution of each ecological system relative to the species' range and habitat requirements;
    3. Examining the observation records for each species in the state-wide point observation database associated with each ecological system;
    4. Calculating the percentage of observations associated with each ecological system relative to the percent of Montana covered by each ecological system to get a measure of "observations versus availability of habitat".
    Species that breed in Montana were only evaluated for breeding habitat use, species that only overwinter in Montana were only evaluated for overwintering habitat use, and species that only migrate through Montana were only evaluated for migratory habitat use.  In general, species were listed as associated with an ecological system if structural characteristics of used habitat documented in the literature were present in the ecological system or large numbers of point observations were associated with the ecological system.  However, species were not listed as associated with an ecological system if there was no support in the literature for use of structural characteristics in an ecological system, even if point observations were associated with that system.  Common versus occasional association with an ecological system was assigned based on the degree to which the structural characteristics of an ecological system matched the preferred structural habitat characteristics for each species as represented in scientific literature.  The percentage of observations associated with each ecological system relative to the percent of Montana covered by each ecological system was also used to guide assignment of common versus occasional association.  If you have any questions or comments on species associations with ecological systems, please contact the Montana Natural Heritage Program's Senior Zoologist.

    Suggested Uses and Limitations
    Species associations with ecological systems should be used to generate potential lists of species that may occupy broader landscapes for the purposes of landscape-level planning.  These potential lists of species should not be used in place of documented occurrences of species (this information can be requested at: http://mtnhp.org/requests/default.asp) or systematic surveys for species and evaluations of habitat at a local site level by trained biologists.  Users of this information should be aware that the land cover data used to generate species associations is based on imagery from the late 1990s and early 2000s and was only intended to be used at broader landscape scales.  Land cover mapping accuracy is particularly problematic when the systems occur as small patches or where the land cover types have been altered over the past decade.  Thus, particular caution should be used when using the associations in assessments of smaller areas (e.g., evaluations of public land survey sections).  Finally, although a species may be associated with a particular ecological system within its known geographic range, portions of that ecological system may occur outside of the species' known geographic range.

    Literature Cited
    • Adams, R.A.  2003.  Bats of the Rocky Mountain West; natural history, ecology, and conservation.  Boulder, CO: University Press of Colorado.  289 p.
    • Dobkin, D. S.  1992.  Neotropical migrant land birds in the Northern Rockies and Great Plains. USDA Forest Service, Northern Region. Publication No. R1-93-34.  Missoula, MT.
    • Foresman, K.R.  2012.  Mammals of Montana.  Second edition.  Mountain Press Publishing, Missoula, Montana.  429 pp.
    • Hart, M.M., W.A. Williams, P.C. Thornton, K.P. McLaughlin, C.M. Tobalske, B.A. Maxell, D.P. Hendricks, C.R. Peterson, and R.L. Redmond. 1998.  Montana atlas of terrestrial vertebrates.  Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, MT.  1302 p.
    • Hutto, R.L. and J.S. Young.  1999.  Habitat relationships of landbirds in the Northern Region, USDA Forest Service, Rocky Mountain Research Station RMRS-GTR-32.  72 p.
    • Maxell, B.A.  2000.  Management of Montana's amphibians: a review of factors that may present a risk to population viability and accounts on the identification, distribution, taxonomy, habitat use, natural history, and the status and conservation of individual species.  Report to U.S. Forest Service Region 1.  Missoula, MT: Wildlife Biology Program, University of Montana.  161 p.
    • Werner, J.K., B.A. Maxell, P. Hendricks, and D. Flath.  2004.  Amphibians and reptiles of Montana.  Missoula, MT: Mountain Press Publishing Company. 262 p.

Original Concept Authors
M.S. Reid

Montana Version Authors
L.K. Vance, T. Luna, S.V. Cooper

Version Date
1/1/2017

References
  • Classification and Map Identifiers

    Cowardin Wetland Classification: Not applicable

    NatureServe Identifiers:
    Element Global ID
    System Code CES306.960, Rocky Mountain Poor Site Lodgepole Pine Forest

    National Land Cover Dataset:
    42: Evergreen Forest

    ReGAP:
    4267: Rocky Mountain Poor Site Lodgepole Pine Forest


  • Literature Cited AboveLegend:   View Online Publication
    • Agee, J.A. 1993. Fire ecology of Pacific Northwest forests. Washington, D.C.: Island Press. 493 p.
    • Anderson, M.D. 2003. Pinus contorta var. latifolia. In: Fire Effects Information System, [Online}. U. S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer).
    • Cochran, P.H. 1985. Soils and productivity of lodgepole pine. Pp. 89-93 In: Baumgartner, D.M., R.G. Krebill, J.T. Arnott, and G.F. Weetman, compilers and editors. Lodgepole pine: The species and its management: Symposium proceedings, May 8-10. Spokane, WA: Washington State University, Cooperative Extension.
    • Hawksworth, F.G., D. Wiens, and B.W. Geils. 2002. Arceuthobium in North America. Mistletoes of North American conifers 29-56.
    • Raffa, K.F., B.H. Aukema, B.J. Bentz, A.L. Carroll, J.A. Hicke, M.G. Turner, and W.H. Romme. 2008. Cross-scale drivers of natural disturbances prone to anthropogenic amplification: the dynamics of bark beetle eruptions. Bioscience 58(6): 501-517.
    • Schoennagel, T., M. G. Turner, and W. H. Romme. 2003. The influence of fire interval and serotiny on postfire lodgepole pine density in Yellowstone National Park. Ecology 84:2967-2978.
    • Smith, J. K. and W. C. Fischer. 1997. Fire ecology of the forest habitat types of northern Idaho. Gen. Tech. Rep. INT-GTR-363. USDA Forest Service, Ogden, UT.
    • Stephens, S.L., J.K. Agee, P.Z. Fulé, M.P. North, W.H. Romme, T.W. Swetnam, and M.G. Turner. 2013. Managing forests and fire in changing climates. Science 342(6154):41-42.
    • U.S. Department of Agriculture, Forest Service, Missoula Fire Sciences Laboratory. 2012. Information from LANDFIRE on Fire Regimes of Rocky Mountain Lodgepole Pine Communities. In: Fire Effects Information System. Missoula, MT: USDA Forest Service, Rocky
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Burns, R. M., and B. H. Honkala, technical coordinators. 1990a. Silvics of North America: Volume 1. Conifers. USDA Forest Service. Agriculture Handbook 654. Washington, DC. 675 pp.
    • Pfister, R. D., B. L. Kovalchik, S. F. Arno, and R. C. Presby. 1977. Forest habitat types of Montana. USDA Forest Service. General Technical Report INT-34. Intermountain Forest and Range Experiment Station, Ogden, UT. 174 pp.

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Citation for data on this website:
Rocky Mountain Poor Site Lodgepole Pine Forest.  Montana Field Guide.  Retrieved on , from