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CEGL000204 Pinus ponderosa / Symphoricarpos occidentalis Forest
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: Ponderosa Pine / Western Snowberry Forest
Colloquial Name: No Data Available
Hierarchy Level: Association
Type Concept: This forest type is an important association in the foothills and lower montane slopes of the Little Rocky Mountains of north-central Montana where it occurs on all aspects of the rounded foothills and on warm aspects of moderate mountain slopes. Elevations range from 1040-1585 m (3400-5200 feet). Soils are loams or sandy loams derived primarily from limestone. Stands have an open to closed canopy of Pinus ponderosa. Symphoricarpos occidentalis, Amelanchier alnifolia, and Prunus virginiana dominate the relatively dense shrub layer. The herbaceous layer is composed of the perennial bunchgrass Pseudoroegneria spicata with a sparse but diverse assemblage of forbs including Anemone multifida and Balsamorhiza sagittata. These warm dry pine forests benefit from periodic surface fire that reduces over-stocking by killing seedling- and sapling-sized trees and lessens the risk of stand-replacing crown fires.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: These forests are common in the Little Rocky Mountains (Roberts 1980) and appear to be a local variant of mesic ponderosa pine forest that is compositionally distinct from other described associations.
Compare this association to ~Pseudotsuga menziesii / Symphoricarpos occidentalis Forest (CEGL000461)$$ that is derived from the Pseudotsuga menziesii / Symphoricarpos occidentalis Habitat Type and also occurs in the Little Rocky Mountains (Roberts 1980). These two associations have nearly identical species composition. The only difference is that Pseudotsuga menziesii is more abundant in the latter with 6% mean canopy cover. This type is also similar to ~Pinus ponderosa / Symphoricarpos albus Forest (CEGL000203)$$ which is common throughout Montana. However, in the Little Rocky Mountains, Symphoricarpos occidentalis replaces Symphoricarpos albus. Occurrences of ~Pinus ponderosa / Symphoricarpos occidentalis Forest (CEGL000204)$$ from this area should be accepted with caution until voucher specimens of Symphoricarpos occidentalis from this mountain range and study area have been examined. If one follows the key of Hansen et al. (1995), most occurrences of ~Pinus ponderosa / Symphoricarpos occidentalis Forest (CEGL000204)$$ would key to ~Pinus ponderosa / Prunus virginiana Forest (CEGL000192)$$ by virtue of having greater than 5% cover of Prunus virginiana and Amelanchier alnifolia. However, their respective landscape settings are to a fair degree non-overlapping. ~Pinus ponderosa / Symphoricarpos occidentalis Forest (CEGL000204)$$ occurs on upland slopes and well-drained sites, whereas CEGL000192 occurs on alluvial benches and toeslopes, where soil moisture is augmented. In mountain ranges of north-central Montana there are north- to northeast-facing slopes, possibly subirrigated, that key to CEGL000204, but that would best be considered CEGL000192 due to their augmented moisture supply.
Compare this association to ~Pseudotsuga menziesii / Symphoricarpos occidentalis Forest (CEGL000461)$$ that is derived from the Pseudotsuga menziesii / Symphoricarpos occidentalis Habitat Type and also occurs in the Little Rocky Mountains (Roberts 1980). These two associations have nearly identical species composition. The only difference is that Pseudotsuga menziesii is more abundant in the latter with 6% mean canopy cover. This type is also similar to ~Pinus ponderosa / Symphoricarpos albus Forest (CEGL000203)$$ which is common throughout Montana. However, in the Little Rocky Mountains, Symphoricarpos occidentalis replaces Symphoricarpos albus. Occurrences of ~Pinus ponderosa / Symphoricarpos occidentalis Forest (CEGL000204)$$ from this area should be accepted with caution until voucher specimens of Symphoricarpos occidentalis from this mountain range and study area have been examined. If one follows the key of Hansen et al. (1995), most occurrences of ~Pinus ponderosa / Symphoricarpos occidentalis Forest (CEGL000204)$$ would key to ~Pinus ponderosa / Prunus virginiana Forest (CEGL000192)$$ by virtue of having greater than 5% cover of Prunus virginiana and Amelanchier alnifolia. However, their respective landscape settings are to a fair degree non-overlapping. ~Pinus ponderosa / Symphoricarpos occidentalis Forest (CEGL000204)$$ occurs on upland slopes and well-drained sites, whereas CEGL000192 occurs on alluvial benches and toeslopes, where soil moisture is augmented. In mountain ranges of north-central Montana there are north- to northeast-facing slopes, possibly subirrigated, that key to CEGL000204, but that would best be considered CEGL000192 due to their augmented moisture supply.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: Pinus ponderosa is the only canopy tree (mean canopy cover of 61%); Pseudotsuga menziesii was present in 8% of stands (<1% cover). The understory is dominated by Symphoricarpos occidentalis (19%), but Amelanchier alnifolia (6%), Juniperus communis (7%), Prunus virginiana (6%), and Shepherdia canadensis (5%) are also common. Pseudoroegneria spicata (6%) is the only constant and common grass. Common forbs include Anemone multifida (2%), Balsamorhiza sagittata (3%), Galium boreale (1%), Solidago missouriensis (1%), and Thermopsis rhombifolia (1%) (Roberts 1980).
Dynamics: Presettlement stands in the warm, dry ponderosa pine habitat types were often open and park-like. Surface fires kept stands in open condition by thinning out seedling- and sapling-sized trees. However, many modern stands have become overstocked as a result of fire suppression. These overstocked stands are more prone to stand-replacing crown fires. Severe crown fires would cause stands to revert to grasslands and/or snowberry thickets (Fischer and Clayton 1983).
Environmental Description: This community occurs on gentle to moderate slopes in foothills and warm aspects of lower mountain slopes at 1040 to 1585 m (3400-5200 feet) (Roberts 1980). Mean annual precipitation is 35-40 cm (Soil Conservation Service 1981b). Soils are loams or sandy loams derived from limestone (primarily) and non-calcareous parent materials. Soil reaction is near-neutral (mean pH=6.9), and average duff depth is 6.4 cm (Roberts 1980).
Geographic Range: This type is known only from the foothills and lower montane slopes on the Little Rocky Mountains in north-central Montana.
Nations: US
States/Provinces: MT
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.688842
Confidence Level: Low
Confidence Level Comments: No Data Available
Grank: G3
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.2 Ponderosa Pine - Douglas-fir - Limber Pine Central Rocky Mountain Dry Forest Macrogroup | M501 | 1.B.2.Nb.2 |
| Group | 1.B.2.Nb.2.e Ponderosa Pine Northwestern Great Plains Forest & Woodland Group | G216 | 1.B.2.Nb.2.e |
| Alliance | A3465 Ponderosa Pine Mesic Black Hills Forest Alliance | A3465 | 1.B.2.Nb.2.e |
| Association | CEGL000204 Ponderosa Pine / Western Snowberry Forest | CEGL000204 | 1.B.2.Nb.2.e |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: = Pinus ponderosa / Symphoricarpos occidentalis Habitat Type (Roberts 1980)
- Bourgeron, P. S., and L. D. Engelking, editors. 1994. A preliminary vegetation classification of the western United States. Unpublished report. The Nature Conservancy, Western Heritage Task Force, Boulder, CO. 175 pp. plus appendix.
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- Hansen, P. L., G. R. Hoffman, and A. J. Bjugstad. 1984. The vegetation of Theodore Roosevelt National Park, North Dakota: A habitat type classification. General Technical Report RM-113. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO. 35 pp.
- Hansen, P. L., R. D. Pfister, K. Boggs, B. J. Cook, J. Joy, and D. K. Hinckley. 1995. Classification and management of Montana''s riparian and wetland sites. Miscellaneous Publication No. 54. Montana Forest and Conservation Experiment Station, School of Forestry, University of Montana. 646 pp. plus posters.
- Hansen, P. L., and G. R. Hoffman. 1988. The vegetation of the Grand River/Cedar River, Sioux, and Ashland districts of the Custer National Forest: A habitat type classification. General Technical Report RM-157. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO. 68 pp.
- MTNHP [Montana Natural Heritage Program]. 2002b. List of ecological communities for Montana. Montana Natural Heritage Program, Montana State Library, Helena, MT.
- Pfister, R. D., B. L. Kovalchik, S. F. Arno, and R. C. Presby. 1977. Forest habitat types of Montana. General Technical Report INT-34. USDA Forest Service, Intermountain Forest and Range Experiment Station, Ogden, UT. 174 pp.
- Roberts, D. W. 1980. Forest habitat types of the Bear''s Paw Mountains and Little Rocky Mountains, Montana. Unpublished thesis, Department of Forestry, University of Montana, Missoula. 116 pp.
- Soil Conservation Service. 1981b. Average annual precipitation Montana. USDA-SCS, Bozeman, MT.
- Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.