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A3369 Abies concolor Southern Rocky Mountain Mesic Forest & Woodland Alliance

Type Concept Sentence: Forests and woodlands included in this alliance consist of stands dominated by Abies concolor or codominated by Populus tremuloides or Pseudotsuga menziesii. They occur in mountain environments from the southern and central Rocky Mountains and east to the Wyoming Basins.


Common (Translated Scientific) Name: White Fir Southern Rocky Mountain Mesic Forest & Woodland Alliance

Colloquial Name: Southern Rocky Mountain Mesic White Fir Forest & Woodland

Hierarchy Level:  Alliance

Type Concept: Forests and woodlands included in this alliance consist of stands dominated by Abies concolor or codominated by Populus tremuloides or Pseudotsuga menziesii. They occur in mountain environments from the southern and central Rocky Mountains and east to the Wyoming basins. In general, these mixed conifer forests have a moderately dense to closed canopy (>60%) with Abies concolor successfully reproducing and typically codominant in the tree canopy. The most common codominant canopy species include Populus tremuloides or Pseudotsuga menziesii. Occasionally these stands occur as woodlands with as little as 10% total canopy cover. Other common canopy associates include Picea pungens, Pinus flexilis, Pinus ponderosa, and Pinus strobiformis. Understories may be shrub-, forb- or graminoid-dominated. The most common dominant shrubs include Acer glabrum, Acer grandidentatum, Holodiscus dumosus, Jamesia americana, Juglans major, Physocarpus malvaceus, Quercus gambelii, and Symphoricarpos oreophilus. Common herbaceous dominants include Erigeron eximius, Lathyrus lanszwertii var. leucanthus, Osmorhiza berteroi, Poa pratensis, and Thalictrum fendleri. These forests occupy a variety of topo-edaphic positions, such as lower and middle slopes of ravines, upper slopes at higher elevations, along stream terraces, ridgetops, and north- and east-facing slopes that burn somewhat infrequently. Parent materials and soils are highly variable and nondefinitive for these forests. Elevations range from 1800-3000 m.

Diagnostic Characteristics: Nearly sparse to dense forests and woodlands where Abies concolor is the primary dominant or codominant with Populus tremuloides or Pseudotsuga menziesii. Indicative of this alliance are understories where Abies concolor is always regenerating. It is distinguished from other Abies concolor alliances in having understories dominated by mesophytic species.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: The former Abies concolor Woodland Alliance (A.553) has been included here. The name of the alliance needs to include better diagnostic species, as this alliance has a name very similar to A3420 (G226). For now, a geographic modifier is used to distinguish it.

Similar NVC Types: No Data Available
note: No Data Available

Physiognomy and Structure: These are open to closed, medium-statured to tall (20-50 m in height), multi-storied forests of needle-leaved evergreen trees. Occasionally a subcanopy (10-20 m tall) of broad-leaved evergreen or cold-deciduous trees may be present. Many densely stocked stands may have a somewhat depauperate understory, but more open stands often have a well-developed ericaceous or cold-deciduous shrub layer. The herbaceous layer is usually dominated by shade-tolerant forbs, but sod-forming or cespitose graminoids may also be common.

Floristics: Forests and woodlands included in this alliance consist of open to closed, medium-statured to tall (20-50 m in height) stands dominated by Abies concolor or codominated by Populus tremuloides or Pseudotsuga menziesii. Occasionally these stands occur as woodlands with as little as 10% total canopy cover. Other common canopy associates include Picea pungens, Pinus flexilis, Pinus ponderosa, and Pinus strobiformis. Understories may be shrub-, forb- or graminoid-dominated. The most common dominant shrubs include Acer glabrum, Acer grandidentatum, Holodiscus dumosus, Jamesia americana, Juglans major, Physocarpus malvaceus, Quercus gambelii, and Symphoricarpos oreophilus. Other shrub associates may include Alnus incana, Amelanchier utahensis, Cornus sericea (= Cornus stolonifera), Juniperus communis, Lonicera arizonica, Lonicera involucrata, Mahonia repens (= Berberis repens), Paxistima myrsinites, Rosa woodsii, Rubus idaeus, and Rubus parviflorus. The herbaceous layer may be quite lush and diverse with shade-tolerant species. Common herbaceous dominants include Erigeron eximius, Lathyrus lanszwertii var. leucanthus, Osmorhiza berteroi, Poa pratensis, and Thalictrum fendleri. Other herbaceous associates may include Aquilegia chrysantha, Artemisia franserioides, Bromus ciliatus var. ciliatus, Bromus ciliatus var. richardsonii (= Bromus richardsonii), Carex siccata (= Carex foenea), Fragaria ssp., Galium mexicanum ssp. asperrimum (= Galium asperrimum), Geranium richardsonii, Koeleria macrantha, Monarda fistulosa var. menthifolia, Oreochrysum parryi, and Osmorhiza depauperata.

Dynamics:  With fire suppression, Abies concolor has vigorously colonized many sites which were formerly occupied by open Pinus ponderosa woodlands. These invasions have dramatically changed the fuel load and potential behavior of fire in these forests. In particular, the potential for high-intensity crown fires has increased. Abies concolor is much more shade-tolerant than Populus tremuloides and is the most important regenerating species under closed-canopy conditions. Most of these mixed stands are seral and will eventually be dominated by Abies concolor. This unique forest alliance is linked to gap-forming disturbances, such as fire or windthrow, which allow regeneration of Populus tremuloides and control abundances of Abies concolor (Mueggler and Campbell 1986, Mueggler 1988).

Environmental Description:  These forests and woodlands occupy a variety of topo-edaphic positions, such as lower and middle slopes of ravines, upper slopes at higher elevations, canyon sideslopes, along stream terraces, ridgetops, scree slopes and north- and east-facing slopes that burn somewhat infrequently. Parent materials and soils are highly variable and nondefinitive for these forests. Annual precipitation averages 50-80 cm, with abundant snowfall, but summer rainfall due to convective storms is also important. Soils are generally slightly acidic, well-drained loams or sandy loams with substantial organic matter. Elevations range from 1800-3000 m.

Geographic Range: This forest alliance occurs mainly in the southern and central Rocky Mountains, but extends west to the Utah Plateaus, south to the Apache Highlands and west into the Wyoming Basins.

Nations: MX?,US

States/Provinces:  AZ, CA?, CO, NM, NV, UT, WY




Confidence Level: Moderate

Confidence Level Comments: No Data Available

Grank: GNR

Greasons: No Data Available

Type Name Database Code Classification Code
Class 1 Forest & Woodland Class C01 1
Subclass 1.B Temperate & Boreal Forest & Woodland Subclass S15 1.B
Formation 1.B.2 Cool Temperate Forest & Woodland Formation F008 1.B.2
Division 1.B.2.Nb Rocky Mountain Forest & Woodland Division D194 1.B.2.Nb
Macrogroup 1.B.2.Nb.1 White Fir - Douglas-fir - Blue Spruce Forest Macrogroup M022 1.B.2.Nb.1
Group 1.B.2.Nb.1.d White Fir - Blue Spruce - Douglas-fir Mesic Southern Rocky Mountain Forest Group G225 1.B.2.Nb.1.d
Alliance A3369 White Fir Southern Rocky Mountain Mesic Forest & Woodland Alliance A3369 1.B.2.Nb.1.d
Association CEGL000240 White Fir - Douglas-fir / Rocky Mountain Maple Forest CEGL000240 1.B.2.Nb.1.d
Association CEGL000241 White Fir / Bigtooth Maple Forest CEGL000241 1.B.2.Nb.1.d
Association CEGL000247 White Fir - Douglas-fir / Spruce-fir Fleabane Forest CEGL000247 1.B.2.Nb.1.d
Association CEGL000248 White Fir / Arizona Walnut Forest CEGL000248 1.B.2.Nb.1.d
Association CEGL000250 White Fir - Douglas-fir / Nevada Pea Forest CEGL000250 1.B.2.Nb.1.d
Association CEGL000253 White Fir / Mountain Sweet-cicely Forest CEGL000253 1.B.2.Nb.1.d
Association CEGL000254 White Fir / Mallow Ninebark Forest CEGL000254 1.B.2.Nb.1.d
Association CEGL000255 White Fir - Blue Spruce - Narrowleaf Cottonwood / Rocky Mountain Maple Forest CEGL000255 1.B.2.Nb.1.d
Association CEGL000263 White Fir / Mountain Snowberry Forest CEGL000263 1.B.2.Nb.1.d
Association CEGL000523 Quaking Aspen - White Fir / Mountain Snowberry Forest CEGL000523 1.B.2.Nb.1.d
Association CEGL000890 White Fir - (Douglas-fir) / Five-petal Cliffbush - Rockspirea Scree Woodland CEGL000890 1.B.2.Nb.1.d
Association CEGL002947 Quaking Aspen - White Fir / Kentucky Bluegrass Ruderal Forest CEGL002947 1.B.2.Nb.1.d
Association CEGL005352 White Fir - (Douglas-fir) / Gambel Oak / Fendler''s Meadowrue Forest CEGL005352 1.B.2.Nb.1.d
Association CEGL005353 White Fir - (Douglas-fir) / Fendler''s Meadowrue Forest CEGL005353 1.B.2.Nb.1.d

Concept Lineage: A.152, A.419, A.553, in parts [covers proto-alliances A2101 & A2112].

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available

Synonomy: >< Abies concolor Series (Johnston 1987)
>< Interior Douglas-fir: 210 (Eyre 1980) [southwestern stands]
>< Western Needleleaf Forests: 20: Spruce-Fir-Douglas fir Forest (Picea-Abies-Pseudotsuga) (Küchler 1964)
>< Western Needleleaf Forests: 5: Mixed Conifer Forest (Abies-Pinus-Pseudotsuga) (Küchler 1964)
>< White Fir: 211 (Eyre 1980)

Concept Author(s): M.E. Hall, in Faber-Langendoen et al. (2013)

Author of Description: M.E. Hall

Acknowledgements: We have incorporated significant descriptive information previously compiled by D. Sarr.

Version Date: 03-14-14

  • Eyre, F. H., editor. 1980. Forest cover types of the United States and Canada. Society of American Foresters, Washington, DC. 148 pp.
  • Faber-Langendoen, D., J. Drake, M. Hall, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, M. Russo, K. Schulz, L. Sneddon, K. Snow, and J. Teague. 2013-2019b. Screening alliances for induction into the U.S. National Vegetation Classification: Part 1 - Alliance concept review. NatureServe, Arlington, VA.
  • Johnston, B. C. 1987. Plant associations of Region Two: Potential plant communities of Wyoming, South Dakota, Nebraska, Colorado, and Kansas. R2-ECOL-87-2. USDA Forest Service, Rocky Mountain Region. Lakewood, CO. 429 pp.
  • Küchler, A. W. 1964. Potential natural vegetation of the conterminous United States. American Geographic Society Special Publication 36. New York, NY. 116 pp.
  • Mueggler, W. F. 1988. Aspen community types of the Intermountain Region. General Technical Report INT-250. USDA Forest Service, Intermountain Research Station, Ogden, UT. 135 pp.
  • Mueggler, W. F., and R. B. Campbell, Jr. 1986. Aspen community types of Utah. Research Paper INT-362. USDA Forest Service, Intermountain Forest and Range Experiment Station, Ogden, UT.