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Montana Field Guides

Rocky Mountain Subalpine Woodland and Parkland

Provisional State Rank: S2
* (see reason below)

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State Rank Reason
Blister rust, insects and drought are all affecting these forests. Although decline has not been as widespread as with some other ecological systems, it is expected to continue, especially if winters are mild.

General Description

This system includes all subalpine and treeline forest associations of the Montana Rocky Mountains and island ranges. It is characteristically a high-elevation mosaic of stunted tree clumps, open woodlands, and herb- or dwarf-shrub-dominated openings, occurring above closed forest ecosystems and below alpine communities. It includes open areas with stands of whitebark pine (Pinus albicaulis) occurring most commonly on south-, east-, and west-facing aspects, or less commonly, alpine larch (Larix lyallii) on north-facing aspects and in basins. Subalpine fir (Abies lasiocarpa) is the co-dominant in these systems and is often the most prevalent tree species. Engelmann spruce (Picea engelmannii) is usually associated with subalpine fir and occurs as either a climax co-dominant or as a persistent, long-lived seral species in most upper elevation subalpine fir habitat types. Elevation range from as low as 1,981 meters (6,500 feet) in northwestern Montana to 2,682 meters (8,800 feet) in southwestern Montana. The climate is typically very cold in winter and dry in summer. Landforms include ridgetops, mountain slopes, glacial trough walls and moraines, talus slopes, landslides and rockslides, and cirque headwalls and basins. Snow accumulation is high in basins, but ridgetops have little snow accumulation because of high winds and sublimation. In this harsh, often wind-swept environment, trees are usually stunted and flagged from damage associated with wind, blowing snow and ice crystals, especially at the upper elevations. Fire suppression, disease, insects and climate change are changing the structure, distribution and composition of these systems.

Diagnostic Characteristics
Subalpine or upper treeline; forest and woodland; oligotrophic soils.

Similar Systems


Whitebark pine-subalpine fir forests and parklands occur throughout the Montana Rocky Mountains and east into the mountain island ranges. This is the most common forest alliance in the drier mountain ranges east of the Continental Divide. It is especially well represented in the Yellowstone Basin and surrounding mountain ranges. The distribution pattern of alpine larch (Larix lyalli) is patchy; the best stands occur near the treeline in the Anaconda-Pintlar, Bitterroot, Cabinet, Whitefish, Swan, southern Mission, Sapphire, and Flint Creek ranges, and in scattered locations in Glacier National Park and at the top of the headwaters of the Teton and Sun River drainages (Arno and Habeck, 1972). Mountain hemlock (Tsuga mertensiana)/subalpine fir is a minor subalpine forest type present in some high mountain cirques along the Montana-Idaho Divide from Lolo to the Cabinet Gorge. Mountain hemlock stands are much more prevalent immediately to the west in Idaho; however, they also occur in small isolated stands in the Whitefish, Mission, and Bitterroot ranges. They are absent from Glacier National Park.

Ecological System Distribution
Approximately 1,628 square kilometers are classified as Rocky Mountain Subalpine Woodland and Parkland 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, Broadwater, Carbon, Cascade, Deer Lodge, Fergus, Flathead, Gallatin, Glacier, Golden Valley, Granite, Jefferson, Judith Basin, Lake, Lewis and Clark, Lincoln, Madison, Meagher, Mineral, Missoula, Park, Pondera, Powell, Ravalli, Sanders, Silver Bow, Stillwater, Sweet Grass, Teton, Wheatland

Spatial Pattern
Large patch

In Montana, these forests form a belt throughout the Montana Rocky Mountains and island ranges. Near the upper elevational limits, these forests and parklands are bordered by alpine meadows and tundra. On especially dry sites east of the Continental Divide, these forests are sometimes bordered by subalpine grasslands. Forests and parklands are diverse in composition and structure due to widely diverse high elevation terrain and extreme climatic conditions. At the upper limits of tree growth, stands and krummholz mats can persist for hundreds of years. This system occurs up to 1,981-2,195 meters (6,500-7,200 feet) in northwestern Montana, 2,225-2438 meters (7,300-8,000 feet) in west-central Montana and island ranges, and 2,469-2,682 meters (8,100-8,800 feet) in southwestern Montana. Soils and parent materials are variable. Alpine larch stands typically develop on granitic and quartzite substrates with little soil development or occasionally on sedimentary materials. Surface soils are usually gravelly loams with large amounts of rock present (Pfister et al., 1977). Whitebark pine-subalpine fir communities can occur on a wide range of parent materials, including calcareous bedrock substrates. Soils are typically gravelly silt loams and silts that range from slightly basic to slightly acidic. Duff layers in both forest types are typically less than 2.5 centimeters (1.0 inch) (Pfister et al., 1977). This forest and woodland system occurs on landforms such as ridgetops, mountain slopes, glacial trough walls and moraines, talus slopes, landslides and rockslides, and cirque headwalls and basins. Snow accumulation is high in basins, but ridgetops have little snow accumulation because of high winds and sublimation. In this harsh, often wind-swept environment, trees are stunted and flagged from damage associated with wind, blowing snow and ice crystals, especially at the upper elevational ecotone.


These forests or patches often originate when Engelmann spruce, alpine larch, or whitebark pine colonize a sheltered site. Alpine larch/subalpine fir communities are prevalent on cool, north- and east-facing exposures west of the Continental Divide. Whitebark pine/subalpine fir communities occur on adjacent, warmer exposures and aspects. Subalpine fir colonizes in the shelter of these speciesand may form a dense canopy by branch layering. This species is capable of remaining dominant within these subalpine and treeline forests due to its longevity and ability to regenerate vegetatively. In the absence of disturbance, it continues to regenerate under shaded conditions. Seed crops are erratic at the lower elevational limit of this system and are virtually absent at treeline. The most common subalpine forest association in Montana is whitebark pine-subalpine fir.

The understories of these forests are usually sparse, but moister sites support mats of ericaceous plants, such as tall huckleberry (Vaccinium membranaceum), dwarf bilberry (Vaccinium myrtillus), or most often, grouse whortleberry (Vaccinium scoparium). Mountain heath (Phyllodoce species) and white mountain heather (Cassiope mertensiana) are commonon sites with more organic matter accumulation. A few taller shrubs such as alpine currant (Ribes montigenum), short fruited willow (Salix brachycarpa), and planeleaf willow (Salix planifolia) may also be present.The herbaceous layer is sparse under dense shrub or tree canopies, but may be dense where the shrub canopy is open or absent. Purple mountain hairgrass (Vahlodea atropurpurea), Hitchcock’s woodrush (Luzula glabrata var. hitchcockii), alpine bluegrass (Poa alpina), Sandberg’s bluegrass (Poa secunda), alpine timothy (Phleum alpinum), pinegrass (Calamagrostis rubescens), Parry’s rush (Juncus parryi) and sedges (Carex species) are the most common graminoids. A wide diversity of forbs are present in open meadows among or adjacent to these forests, typically including species such as arnica (Arnica species), subalpine wandering daisy (Erigeron peregrinus), arrowleaf groundsel (Senecio triangularis), aster (Symphyotrichum species), sibbaldia (Sibbaldia procumbens), glacier lily (Erythronium grandiflorum), rhexi-leaf paintbrush (Castilleja rhexifolia), western windflower (Anemone occidentalis), alpine St. John’s wort (Hypericum formosum), diverse leaf cinquefoil (Potentilla diversifolia), and penstemon (Penstemon species).

Alpine larch stands generally occur at or near upper treeline in north-facing cirques or on slopes where snowfields persist until June or July (Arno and Habeck, 1972). Typical stands are often isolated pockets of open, parklike groves. Alpine larch is considered a pioneer species in these high, north-facing aspects on rocky sites with little soil development, and due to its longevity (up to 1,000 years), is persistent on these sites. Typically, undergrowth in alpine larch stands can be limited due to high rock cover and limited soil development, but will often includes pink mountain heath (Phyllodoce empetriformis), Hitchcock’s woodrush and subalpine fir.

Alliances and Associations
  • (A.811) Subalpine Fir - Engelmann Spruce - Limber Pine Krummholz Shrubland Alliance
  • (A.168) Subalpine Fir - Engelmann Spruce Forest Alliance
  • (A.631) Subalpine Larch Woodland Alliance
  • (A.560) Whitebark Pine - Subalpine Fir Woodland Alliance
  • (A.132) Whitebark Pine Forest Alliance
  • (A.531) Whitebark Pine Woodland Alliance

Dynamic Processes

Major disturbances in this system include fire, avalanches, and biotic vectors. Historically, stand-replacing fires occurred infrequently in this system, at least where open woodlands limited fire severity and spread (Arno, 1980). These tree species are very susceptible to fire.Whitebark pine and subalpine firhave some tolerance to low and moderate severity fire if old individual trees have developed thick bark.Lightning damage to individual trees is common, but sparse canopies and rocky terrain historically limited the spread of fire. More recently, stand-replacing fires caused by lightning strikes are becoming more common, especially in areas of steep terrain. In precipitous mountain areas that receive heavy snowfall, avalanches are common and can remove broad swaths of subalpine forest.

Insects and disease can play a major role in the successional direction of these forests. Whitebark pine is affected by white pine blister rust and mountain pine beetle and is experiencing marked decline. Subalpine firis becoming more prevalent in these forests due to high blister rust mortality. Blister rust mortality is especially high in northwestern Montana, where the moister Pacific maritime climate at high elevations is more conducive to infection than the drier air in the southern mountain ranges. Throughout Montana, both subalpine fir and spruce are affected by spruce bud worm attacks, and large stands of these subalpine forests can be killed following several years of drought or unusually mild winters. Warming climate patterns can result in increases of tree seedling recruitment and density at the upper elevation limit of this ecological system (Klasner and Fagre, 2002).

In the absence of natural fire, periodic prescribed surface burns can be implemented during late fall months to maintain, enhance, and restore this system.

Restoration Considerations
Small-scale prescribed burning during late fall after several hard frosts is recommended to facilitate whitebark pine regeneration by providing open sites on exposed mineral soils suitable for Clark's nutcracker seed caching and seedling establishment. Because light severity burns do not prepare as good a seedbed as more severe burns (McCaughey, 1990), outplanting with disease resistant whitebark pine nursery stock may be needed in some cases.

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: 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
C. Chappell, R. Crawford, G. Kittel, mod. M.S. Reid

Montana Version Authors
T. Luna, M.M. Hart, L.K. Vance

Version Date

  • Classification and Map Identifiers

    Cowardin Wetland Classification: Not applicable

    National Vegetation Classification Standard:
    Class Mesomorphic Tree Vegetation (Forest and Woodland)
    Subclass Temperate Forest
    Formation Cool Temperate Forest
    Division Western North America Cool Temperate Forest
    Macrogroup Rocky Mountain Subalpine and High Montane Conifer Forest

    NatureServe Identifiers:
    Element Global ID
    System Code CES306.807, Northern Rocky Mountain Subalpine Woodland and Parkland

    National Land Cover Dataset:
    42: Evergreen Forest

    4233: Northern Rocky Mountain Subalpine Woodland and Parkland

  • Literature Cited AboveLegend:   View Online Publication
    • Arno, S.F. and R.J. Hoff. Silvics of whitebark pine (Pinus albicaulis). 1989. General Technical Report INT-253. Ogden, UT. USDA, Forest Service, Intermountain Research Station. 11pp.
    • Bockino, N.K.and D.B. Tinker. 2012. Interactions of white pine blister rust and mountain pine beetle in whitebark pine ecosystems in the southern Greater Yellowstone Area. Natural Areas Journal 32(1):31-40.
    • Bower, A.D. and S.N. Aitken. 2008. Ecological genetics and seed transfer guidelines for Pinus albicaulis (Pinaceae). American Journal of Botany 95(1):66-76.
    • Callaway, R.M. 1998. Competition and facilitation on elevation gradients in subalpine forests of the northern Rocky Mountains, USA. Oikos 561-573.
    • Fryer, J.L. 2002. Pinus albicaulis. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.
    • Habeck, R. J. 1991. Larix lyallii. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.
    • Keane, R.E. and R.A. Parsons. 2010. Restoring whitebark pine forests of the northern Rocky Mountains, USA. Ecological Restoration 28(1):56-70.
    • McCaughey, W., G.L. Scott,and K.L. Izlar. 2009. Technical note: whitebark pine planting guidelines. Western Journal of Applied Forestry 24(3):163-166.
    • McCaughey, W.W. and D.F. Tomback. 2001. The natural regeneration process. pp105-120. In: Whitebark pine communities: ecology and restoration. Washington D.C.: Island Press.
    • McKinney, S.T. and D.F. Tomback. 2007. The influence of white pine blister rust on seed dispersal in whitebark pine. Canadian Journal of Forest Research 37(6);1044-1057.
    • Smith, C.M., B. Shepherd, C. Gillies,and J. Stuart-Smith. 2012. Changes in blister rust infection and mortality in whitebark pine over time. Canadian journal of forest research 43(1):90-96.
    • Smith-Mckenna, E.K., L.M. Resler, D.F. Tomback, H. Zhang, and G.P. Malanson. 2013. Topographic influences on the distribution of white pine blister rust in Pinus albicaulis treeline communities. Ecoscience. 20:(3): 215-229.
    • Sturrock, R.N., S.J. Frankel, A.V. Brown, P.E. Hennon, J.T. Kliejunas, K.J. Lewis, and A.J. Woods. 2011. Climate change and forest diseases. Plant Pathology 60(1):133-149.
    • Tomback, D.F. 2005. The impact of seed dispersal by Clark’s nutcracker on whitebark pine: multi-scale perspective on a high mountain mutualism. pp. 181-201. In: Mountain Ecosystems. Springer Berlin Heidelberg.
    • Tomback, D.F., K.G. Chipman, L.M. Resler, E.K. Smith-McKenna, and C.M. Smith. 2014. Relative abundance and functional role of whitebark pine at treeline in the Northern Rocky Mountains. Arctic, Antarctic, and Alpine Research 46(2):407-418.
    • U.S. Department of Agriculture, Forest Service, Missoula Fire Sciences Laboratory. 2012. Information from LANDFIRE on Fire Regimes of Whitebark Pine Communities. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service
    • Uchytil, R.J. 1991. Abies lasiocarpa. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Arno, S. F. 1980. Forest fire history in the northern Rockies. Journal of Forestry 78(8):460-465.
    • Arno, S. F., and J. R. Habeck. 1972. Ecology of alpine larch (Larix lyallii Parlatore) in the Pacific Northwest. Ecological Monographs 42:417-450.
    • Klasner, Frederick L., and Daniel B. Fagre. 2002. "A Half Century of Change in Alpine Treeline Patterns at Glacier National Park, Montana, U.S.A.". Arctic, Antarctic, and Alpine Research. 34 (1): 49-56.
    • McCaughey, W. 1990. Biotic and microsite factors affecting Pinus albicaulis establishment and survival. M.S. thesis, Montana State University, Bozeman. 78 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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Rocky Mountain Subalpine Woodland and Parkland — Northern Rocky Mountain Subalpine Woodland and Parkland.  Montana Field Guide.  Retrieved on , from