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CEGL000767 Pinus discolor / Muhlenbergia emersleyi Woodland
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: Border Pinyon / Bullgrass Woodland
Colloquial Name: No Data Available
Hierarchy Level: Association
Type Concept: This woodland association occurs in southeastern Arizona, southern New Mexico, and likely in adjacent Mexico. Stands occur on gently to moderately sloping alluvial plains, bajadas and canyon bottoms to steep rocky slopes in canyons, piedmont hills and mountains. Elevation ranges from 1460-2010 m (4780-6600 feet). Soils are shallow, gravelly or stony sandy loams or sandy clay loams, derived from a mixture of alluvium and colluvium. The vegetation is characterized by an open to moderately dense tree layer (15-70% cover) dominated by Pinus discolor and Juniperus deppeana. Evergreen oaks are often present in the tree subcanopy but generally have lower cover. An open shrub layer may be present, but the understory is typically dominated by the graminoid layer. The tree canopy ranges from 3 m to over 5 m tall. Stands range from open woodlands to moderately dense woodlands at higher elevations and in canyon bottoms. Other canopy trees are Quercus arizonica, Quercus emoryi, or Quercus grisea. A sparse to moderately dense shrub layer may be present, but graminoids dominate the understory. Characteristic shrubs and succulents include Acacia angustissima, Arctostaphylos pungens, Cercocarpus montanus, Dasylirion wheeleri, Fendlera rupicola, Garrya wrightii, Nolina microcarpa, Quercus toumeyi, Rhus trilobata, Yucca baccata, and Yucca madrensis. The graminoid layer is moderate to dense (25-80% cover) and is typically dominated by medium-tall bunchgrasses such as Bouteloua curtipendula, Eragrostis intermedia, or Muhlenbergia emersleyi, but it can be very diverse with both forbs and grasses.
Diagnostic Characteristics: A grassy woodland on moderate to steep slopes occurring in southeastern Arizona and southwestern New Mexico. Muhlenbergia emersleyi is usually present, although it may be lacking in some locations. Pinus discolor and Juniperus deppeana dominate the overstory, and oaks are present but scarce in the overstory.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: The single plot sampled at Buenos Aires National Wildlife Refuge is codominated by Quercus emoryi in the tree subcanopy but was classified to this pinyon-juniper woodland as a "best fit" because of the high cover of Pinus discolor (40%) and Juniperus deppeana (30%), and the relatively low cover of evergreen oaks did not dominate the stand (encinal).
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: The vegetation is characterized by an open to moderately dense tree layer (15-70% cover) dominated by Pinus discolor and Juniperus deppeana. Evergreen oaks are often present in the tree subcanopy but generally have lower cover. An open shrub layer may be present, but the understory is typically dominated by the graminoid layer. The tree canopy ranges from 3 m to over 5 m tall. Stands range from open woodlands to moderately dense woodlands at higher elevations and in canyon bottoms. Other canopy trees are Quercus arizonica, Quercus emoryi, or Quercus grisea. A sparse to moderately dense shrub layer may be present, but graminoids dominate the understory. Characteristic shrubs and succulents include Acacia angustissima, Arctostaphylos pungens, Cercocarpus montanus, Dasylirion wheeleri, Fendlera rupicola, Garrya wrightii, Nolina microcarpa, Quercus toumeyi, Rhus trilobata, Yucca baccata, and Yucca madrensis (= Yucca schottii). The graminoid layer is moderate to dense (25-80% cover) and is typically dominated by medium-tall bunchgrasses such as Bouteloua curtipendula, Eragrostis intermedia, or Muhlenbergia emersleyi, but it can be very diverse with both forbs and grasses.
Dynamics: No Data Available
Environmental Description: This woodland association occurs in southeastern Arizona, southern New Mexico, and likely in adjacent Mexico. Stands occur on gently to moderately sloping alluvial plains, bajadas and canyon bottoms to steep rocky slopes in canyons, piedmont hills and mountains. Elevation ranges from 1460-2010 m (4780-6600 feet). Soils are shallow, gravelly or stony sandy loams or sandy clay loams, derived from a mixture of alluvium and colluvium.
Geographic Range: These woodlands occur in the mountains of southern New Mexico and southeastern Arizona. They likely also occur in the mountains of the Mexican states of Chihuahua and Sonora.
Nations: MX?,US
States/Provinces: AZ, MXCHH?, MXSON?, NM
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.684660
Confidence Level: Low - Poorly Documented
Confidence Level Comments: No Data Available
Grank: G5
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.1 Warm Temperate Forest & Woodland Formation | F018 | 1.B.1 |
| Division | 1.B.1.Nd Madrean-Balconian Forest & Woodland Division | D060 | 1.B.1.Nd |
| Macrogroup | 1.B.1.Nd.1 Alligator Juniper - Mexican Pinyon - Arizona White Oak Madrean Lowland Evergreen Woodland Macrogroup | M010 | 1.B.1.Nd.1 |
| Group | 1.B.1.Nd.1.c Mexican Pinyon - Border Pinyon - Redberry Juniper Woodland Group | G200 | 1.B.1.Nd.1.c |
| Alliance | A3132 Mexican Pinyon - Border Pinyon - Two-needle Pinyon / Grass Understory Woodland Alliance | A3132 | 1.B.1.Nd.1.c |
| Association | CEGL000767 Border Pinyon / Bullgrass Woodland | CEGL000767 | 1.B.1.Nd.1.c |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: = Pinus discolor / Muhlenbergia emersleyi (Stuever and Hayden 1997b)
- Bassett, D., M. Larson, and W. Moir. 1987. Forest and woodland habitat types of Arizona south of the Mogollon Rim and southwestern New Mexico. Edition 2. USDA Forest Service, Southwestern Region, Albuquerque, NM.
- 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.
- Moir, W. H. 1982. A fire history of the high Chisos, Big Bend National Park, Texas. Southwest Naturalist 27:87-98.
- Moir, W. H., and J. O. Carleton. 1987. Classification of pinyon-juniper (P-J) sites on national forests in the Southwest. Pages 216-226 in: R. L. Everett, editor. Proceedings of the Pinyon-Juniper Conference, Reno, NV, 13-16 January 1986. General Technical Report. USDA Forest Service, Intermountain Forest and Range Experiment Station, Ogden, UT. 581 pp.
- Schulz, K. A. 2004. Vegetation classification of Buenos Aires National Wildlife Refuge, Arizona. Unpublished report submitted to USDI Fish and Wildlife Service. NatureServe, Western Regional Office, Boulder, CO.
- Stuever, M. C., and J. S. Hayden. 1997b. Plant associations of Arizona and New Mexico. Volume 2: Woodlands. USDA Forest Service, Southwestern Region, Habitat Typing Guides. 196 pp.
- USFS [U.S. Forest Service]. 1986. Forest and woodland habitat types (plant associations) of southern New Mexico and central Arizona (north of the Mogollon Rim). USDA Forest Service, Southwestern Region, Albuquerque, NM. Second edition, 140 pp. plus insert.
- Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.