Montane Mesic Coniferous (Grand Fir - Douglas-fir - Western Larch) Forest
Global Name:
Central Rocky Mountain-Interior Mesic Grand Fir - Douglas-fir - Western Larch Forest
Global Rank:
G4G5
State Rank:
S4S5
(see reason below)
External Links
State Rank Reason
Relatively secure type due to its large extent, condition, and the few, widespread and/or severe threats.
General Description
This National Vegetation Classification Group is dominated by Western Larch (Larix occidentalis), Grand Fir (Abies grandis) and/or Douglas-fir and are common in western Montana. Western Larch and Grand Fir occur west of the Continental Divide while some mesic Douglas-fir stands in this group occur east of the Divide. Most of the forests in this group occur west of the Continental Divide in areas influenced by more maritime, Pacific air masses. Elevations at these sites range from about 2,000 to 5,500ft. East of the Divide, this group is represented by mesic Douglas-fir forests that occur mostly between 5,200 and 6,800 ft (Pfister et al. 1977).
Occurrences of this group may be found on all slopes and aspects but grow best on sites with high soil moisture, such as valley bottoms, on benches, mesic slopes and moist ravines. Western Larch may form almost pure stands in some settings, particularly in the decades following a stand-replacing fire. Whereas, Grand fir often occurs in mixed conifer stands with an assortment of other species, including Douglas-fir, Western Larch, Ponderosa Pine, Lodgepole Pine, Western Redcedar and/or Western Hemlock. Which of these species co-occurs with Grand Fir at a site, is largely dependent upon geographic location, successional status and moisture regime. Douglas-fir dominated communities within this group include the most mesic Associations with Douglas-fir as a dominant or co-dominant component. Other dry to mesic Douglas-fir dominated or co-dominated sites are included in groups G210 and G215. Structure of the stands in this group vary widely from open to close-canopied and even-aged (primarily only in the case of Western larch) or multi-aged and multi-storied. Understory vegetation may be largely shrubby or herbaceous-dominated or a mix of the two.
This group incorporates portions of the Rocky Mountain Mesic Montane Mixed Conifer Forest Ecological System and the Rocky Mountain Dry-Mesic Montane Mixed Conifer Forest Ecological System.
Diagnostic Characteristics
Mesic Conifer Forests; Montane Zone; Inland Pacific Northwest and Rocky Mountains; Mesic Douglas-fir (Pseudotsuga menziesii) Communities; Mixed Severity and Stand Replacing Fires.
Typical Dominants: Grand Fir (Abies grandis), Western Larch (Larix occidentalis), Douglas-fir (Pseudotsuga menziesii)
Similar Systems
Range
In Montana, this group occurs west of the Continental Divide from the southern Bitterroot Valley north to the Canadian border. It may be found in all the major mountain ranges and major river drainages within this area. East of the Divide, it is found in more localized patches in mesic sites at mid-montane elevations in many of the isolated mountain ranges.
In Montana, G211 occurs within these Level III Ecoregions: 15 (Northern Rockies), 16 (Idaho Batholith), northwestern portion of 17 (Middle Rockies), and 41 (Canadian Rockies).
In Montana, G211 occurs within these Major Land Resource Areas: 43A-Northern Rocky Mountains; 43B-Central Rocky Mountains, and 44A - Northern Rocky Mountain Valleys.
Density and Distribution
Based on 2025 land cover layer. Grid on map is based on USGS 7.5 minute quadrangle map boundaries.
Mapped Distribution by County
Beaverhead, Flathead, Glacier, Lake, Lewis and Clark, Lincoln, Mineral, Missoula, Pondera, Powell, Ravalli, Sanders, Teton
Based on 2025 land cover layer.
Spatial Pattern
Large Patch-Matrix
Environment
These forests occur primarily west of the Continental Divide in areas influenced by more maritime, Pacific air masses. Elevations at these sites range from about 2,000 to 5,500ft. East of the Divide, this group is represented by mesic Douglas-fir forests that occur mostly between 5,200 and 6,800 ft (Pfister etal 1977). Occurrences may be found on all slopes and aspects but grow best on sites with high soil moisture, such as valley bottoms, on benches, mesic slopes and moist ravines. Annual precipitation occurs as a mix of rain and snow, with snow common from November-March in these habitats.
Vegetation
Forests in this group are dominated by Western Larch (Larix occidentalis), Grand Fir (Abies grandis) and/or Douglas-fir. Western Larch and Grand Fir occur west of the Continental Divide while some mesic Douglas-fir stands in this group occur east of the Divide. Western Larch may form almost pure stands in some settings, particularly in the decades following a stand-replacing fire. Whereas, Grand fir often occurs in mixed conifer stands with an assortment of other species, including Douglas-fir, Western Larch, Ponderosa Pine, Lodgepole Pine, Western Redcedar and/or Western Hemlock. Which of these species co-occurs with Grand Fir at a site, is largely dependent upon geographic location, successional status and moisture regime. Douglas-fir dominated communities within this group include the most mesic Associations with Douglas-fir as a dominant or co-dominant component. On the west side of Glacier National Park, Paper Birch (Betula papyrifera) co-dominates some sites. Structure of the stands vary widely from open to close-canopied and even-aged (primarily only in the case of Western larch) or multi-aged and multi-storied.
Understory vegetation may be largely shrubby or herbaceous-dominated or a mix of the two. Common shrubs include Ninebark (Physocarpus malvaceous), Common Huckleberry (Vaccinium membranaceum), Dwarf Huckleberry (Vaccinium cespitosum), False Huckleberry (Menziesia ferruginea), Serviceberry (Amelanchier alnifolia) Mountain-lover (Paxistima myrsinites) and shrubby-statured Pacific yew (Taxus brevifolia). Forb and subshrub diversity ranges from depauperate to abundant at these sites, and common species include Queencup Beadlily (Clintonia uniflora), Beargrass (Xerophyllum tenax), Bunchberry Dogwood (Cornus canadensis), Twinflower (Linnaea borealis), Arnica (Arnica cordifolia and A. latifola) Western Sweet-cicely (Osmorhiza berteroi) and Cow-parsnip (Heracleum maximum).
Graminoids usually form a very minor component of these stands and may include Bromus vulgaris, Pinegrass (Calamagrostis rubescens) and Elk Sedge (Carex geyeri). Ferns such as Oak Fern (Gymnocarpus dryopteris) may be present in Grand Fir communities. Mosses and lichens may be common in Grand Fir and Douglas-fir communities. Non-native species may be present to abundant in some stands, including both perennial forbs and perennial grasses. A variety of non-native perennial forbs occur at these sites including Canada thistle (Cirsium arvense) and Bull Thistle (Cirsium vulgare). Non-native grasses are more common in some lower elevation Western Larch stands, Common Timothy (Phleum pratense) being one of them.
In Montana, this group is represented by 23 Associations grouped into 2 Alliances, which likely covers the range of vegetation types present in the state within this group.
National Vegetation Classification
Download the complete NVC hierarchy for Montana
TT2 B02 Temperate-Boreal Forest and Woodland
TT2.b S92 Cool Temperate Forest and Woodland
TT2.b3 F112 Temperate Continental Conifer Forest and Woodland
TT2.b3.Nb D337 Rocky Mountain Foothills and Montane Forest and Woodland
TT2.b3.Nb.2 M500 Central Rocky Mountain-Interior Moist Montane Forest
TT2.b3.Nb.2.a G211 Central Rocky Mountain-Interior Mesic Grand Fir - Douglas-fir - Western Larch Forest
A0275 Larix occidentalis Central Rocky Mountain Forest Alliance
CEGL005880 Larix occidentalis / Clintonia uniflora Forest
CEGL005881 Larix occidentalis / Clintonia uniflora - Xerophyllum tenax Forest
CEGL005882 Larix occidentalis / Vaccinium cespitosum Forest
CEGL005883 Larix occidentalis / Vaccinium cespitosum / Clintonia uniflora Forest
A3362 Abies grandis - Pseudotsuga menziesii Central Rocky Mountain Forest and Woodland Alliance
CEGL000176 Pinus monticola / Clintonia uniflora Forest
CEGL000269 Abies grandis / Asarum caudatum Forest
CEGL000272 Abies grandis / Clintonia uniflora Forest
CEGL000275 Abies grandis / Linnaea borealis Forest
CEGL000277 Abies grandis / Physocarpus malvaceus Forest
CEGL000281 Abies grandis / Spiraea betulifolia Forest
CEGL000283 Abies grandis / Taxus brevifolia Forest
CEGL000293 Abies grandis / Xerophyllum tenax Forest
CEGL000432 Pseudotsuga menziesii / Cornus canadensis Forest
CEGL000465 Pseudotsuga menziesii / Vaccinium cespitosum Forest
CEGL000466 Pseudotsuga menziesii / Vaccinium membranaceum Forest
CEGL000467 Pseudotsuga menziesii / Viola adunca var. adunca Forest
CEGL000916 Abies grandis / Calamagrostis rubescens Woodland
CEGL005850 Pseudotsuga menziesii / Clintonia uniflora Forest
CEGL005851 Pseudotsuga menziesii / Menziesia ferruginea / Clintonia uniflora Forest
CEGL005852 Pseudotsuga menziesii / Vaccinium membranaceum / Xerophyllum tenax Forest
CEGL005853 Pseudotsuga menziesii / Heracleum maximum Forest
CEGL005854 Pseudotsuga menziesii / Clintonia uniflora - Xerophyllum tenax Forest
CEGL005904 Betula papyrifera - Conifer / Clintonia uniflora Woodland
*Disclaimer: Some Alliances and Associations are considered provisional. Some require further documentation to verify their occurrence in the state
and some may be modified or deleted in future revisions after collection of additional data and information.
Dynamic Processes
Historically, fires were an important process within many of these communities. Both stand-replacement fires with 150 to 500-year return intervals, and moderate-severity fire with intervals of 50-100 years were important within this group. Grand Fir forests include many sites dominated by Douglas-fir and Ponderosa Pine which were formerly maintained by wildfire, and may now be dominated by Grand Fir (a fire-sensitive, shade-tolerant species) due to fire exclusion (Lillybridge et al. 1995, Chappell et al. 1997). Pre-European settlement fire regimes were typically of frequent, low-intensity surface fires, maintaining relatively open stands of a mix of fire-resistant species. With the advent of effective fire suppression, longer fire-return intervals are now the rule, and mixed-stature stands with Grand Fir in various size classes now create ladder fuels making these forests more susceptible to high-intensity, stand-replacing fires (Cooper et al. 1987, Lillybridge et al. 1995).
Western Larch is a long-lived species in excess of 700 years in the northern Rocky Mountains. However, the life of Larch-dominated stands probably rarely exceeds 250 years due to various mortality sources and the growth of shade-tolerant species, especially on mesic sites. Western Larch stands are generated by stand-replacing fire, the fire-return interval for which is speculated to be approximately 80 to 200 years (Cooper et al. 1987). These sites may be maintained in a seral status for hundreds of years since Western Larch is a long-lived species and the understory is often dominated by Douglas-fir, which will grow into the upper canopy. The potential dominants, typically Subalpine Fir, Engelmann Spruce, and/or Grand Fir establish and grow on these sites, presenting the distinct probability, given the fire-return intervals for this type, that the "climax" (long-term stable) condition is never attained. It has been noted in northern Idaho that, following disturbance (particularly logging) in some mesic-site occurrences, Western Larch does not necessarily replace itself, the first tree-dominated successional stages being dominated by Douglas-fir, Lodgepole Pine, or less frequently by more shade-tolerant species (Cooper et al. 1987); this response is a consequence of the episodic nature of favorable cone crop years in Western larch.
Species Associated with this Community
- How Lists Were Created and Suggested Uses and Limitations
Animal Species Associations
Please note that while all vertebrate species have been systematically associated with vegetation communities, only a handful of invertebrate species have been associated with vegetation communities and invertebrates lists for each vegetation community should be regarded as incomplete. Animal species associations with natural vegetation communities that they regularly breed or overwinter in or migrate through were made by:
- 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, Werner et al. 2004, Adams 2003, and Foresman 2012);
- Evaluating structural characteristics and distribution of each vegetation community relative to the species' range and habitat requirements;
- Examining the observation records for each species in the state-wide point observation database associated with each vegetation community;
- Calculating the percentage of observations associated with each vegetation community relative to the percent of Montana covered by each vegetation community 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. Species that only migrate through Montana were only evaluated for migratory habitat use. In general, species are listed as associated with a vegetation community if it contains structural characteristics known to be used by the species. However, species are not listed as associated with a vegetation community if we found no support in the literature for the species’ use of structural characteristics of the community even if point observations were associated with it. If you have any questions or comments on animal species associations with vegetation communities, please contact the Montana Natural Heritage Program's Senior Zoologist.
Plant Species Associations
Please note that while diagnostic, dominant, or codominant vascular plant species for a vegetation community have been systematically assigned to those communities and vascular plant Species of Concern were systematically evaluated for their associations with vegetation communities, the majority of Montana’s vascular plant species have not been evaluated for their associations with vegetation communities and no attempt has been made to associate non-vascular plants, fungi, or lichens with vegetation communities. Plant species associations with natural vegetation communities were made in a manner similar to that described above for animals, but with review of Lesica et al. (2022) and specimen collection data from the Consortium of Pacific Northwest Herbaria. If you have any questions or comments on plant species associations with vegetation communities, please contact the Montana Natural Heritage Program's Program Botanist.
Suggested Uses and Limitations
Species associations with vegetation communities 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 or predicted habitat suitability models (this information can be requested at: https://mtnhp.mt.gov/requests/), or systematic surveys for species and onsite evaluations of habitat by trained biologists. Users of this information should be aware that the land cover data used to generate species associations is based on satellite imagery from 2016 and was only intended to be used at broader landscape scales. Land cover mapping accuracy is particularly problematic when the vegetation communities 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 vegetation community within its known geographic range, portions of that vegetation community 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.
- Consortium of Pacific Northwest Herbaria. https://www.pnwherbaria.org/ Last accessed May 30, 2025.
- 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.
- Lesica P., M. Lavin, and P.F. Stickney. 2022. Manual of vascular plants, 2nd Edition. Brit Press. 779 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.
- Species of Concern Associated with this Community
Vascular Plants
Mammals
Birds
Reptiles
Amphibians
- Diagnostic, Dominant, or Codominant Plant Species for this Community
Vascular Plants
- Other Native Species Commonly Associated with this Community
Vascular Plants
Original Concept Authors
M.S. Reid, R. Crawford and M. Manning
Montana Version Authors
S. Mincemoyer
Version Date
12/4/2024
References
- Literature Cited AboveLegend:
View Online Publication
Chappell, C., R. Crawford, J. Kagan, and P. J. Doran. 1997. A vegetation, land use, and habitat classification system for the terrestrial and aquatic ecosystems of Oregon and Washington. Unpublished report prepared for Wildlife habitat and species associations within Oregon and Washington landscapes: Building a common understanding for management. Prepared by Washington and Oregon Natural Heritage Programs, Olympia WA, and Portland, OR. 177 pp.- Cooper, S.V., K.E. Neiman, R. Steele, D.W. Roberts. 1987. Forest habitat types of northern Idaho: a second approximation. USDA Forest Service, Intermountain Research Station. General Technical Report INT-236. 135 pp.
- Lillybridge, T. R., B. L. Kovalchik, C. K. Williams, and B. G. Smith. 1995. Field guide for forested plant associations of the Wenatchee National Forest. USDA Forest Service General Technical Report PNW-GTR-359, Pacific Northwest Research Station, Portland. Portland, OR. 335 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.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?- Alexander, M.E. and F.G. Hawksworth. 1976. Fire and dwarf mistletoes in North American coniferous forests. Journal of Forestry 74(7):446-449.
- Arno, S. 1979. Forest regions of Montana. Research paper Int-218, USFS Intermountain and Range Experiment Station, Ogden, Utah.
- Barrett, S.W., S.F. Arno, and C.H. Key. 1991. Fire regimes of western larch-lodgepole pine forests in Glacier National Park, Montana. Canadian Journal of Forest Research 21(12):1711-1720.
- Hawksworth, F.G., D. Wiens, and B.W. Geils. 2002. Arceuthobium in North America. Mistletoes of North American conifers 29-56.
- Howard, J.L. and K.C. Aleksoff. 2000. Abies grandis. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.
- Negron, J.F., W.C. Schaupp, K.E. Gibson, J. Anhold, D. Hansen, R. Their, and P. Mocettini. 1999. Estimating extent of mortality associated with the Douglas-fir beetle in the central and northern Rockies. Western Journal of Applied Forestry 14(3):121-127.
- Scher, J.S. 2002. Larix occidentalis. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.
- Six, D.L. and K. Skov. 2009. Response of bark beetles and their natural enemies to fire and fire surrogate treatments in mixed-conifer forests in western Montana. Forest Ecology and Management 258(5):761-772.
- Steinberg, P. D. 2002. Pseudotsuga menziesii var. glauca. In: Fire Effects Information System, [Online}. U. S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.
- Web Search Engines for Articles on "Central Rocky Mountain-Interior Mesic Grand Fir - Douglas-fir - Western Larch Forest"
