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CEGL005649 Pinus edulis - Juniperus (monosperma, deppeana) / Cercocarpus montanus - Mixed Shrubs Woodland

Type Concept Sentence: No Data Available

Common (Translated Scientific) Name: Two-needle Pinyon - (One-seed Juniper, Alligator Juniper) / Alderleaf Mountain-mahogany - Mixed Shrubs Woodland

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This widespread woodland association occurs in foothills in the southern Rocky Mountains east of the Continental Divide in southern Colorado and New Mexico, extending east into the southwestern Great Plains the hills, canyons, escarpments and other breaks. It can be found on any slope position, though lower slopes are less common. Elevations range from 1472 to 2480 m (4830-8135 feet). Stands occur on gentle to steep slopes on all aspects. The soils are variable but generally shallow, poorly developed and skeletal, ranging from clayey marl to loamy sands. The unvegetated surface is characterized by bedrock, large and small rocks, and/or bare soil with little litter. Sandstone or shale are the most common parent materials. This association is characterized by an open to moderately dense tree canopy (10-60% cover) dominated by a combination of Pinus edulis and Juniperus spp. with a shrub layer dominated by Cercocarpus montanus. The tree canopy averages 2-5 m tall, but some stands may be as tall as 10 m. Pinus edulis and Juniperus monosperma codominate in most stands, but sometimes one may be more prevalent than the other. Other species of Juniperus may be present varying with geography and elevation such as Juniperus deppeana southern extent or and Juniperus scopulorum in higher elevation stands and along drainages. Juniperus osteosperma is not present. The total shrub cover may range from sparse to moderate. Cercocarpus montanus is the dominant shrub with up to 35% cover. It typically occurs as a short shrub but can be a tall shrub on some sites. Other shrubs may be present, including Amelanchier spp., Artemisia bigelovii, Artemisia tridentata, Chrysothamnus viscidiflorus, Gutierrezia sarothrae, Fendlera rupicola, Garrya ovata, Mahonia spp., Nolina microcarpa, Quercus gambelii, Quercus grisea, Rhus trilobata, or species of Yucca and Opuntia. Herbaceous cover is variable, ranging from sparse to moderately dense, and generally dominated by graminoids (>5% cover) with scattered forbs. Extremely open stands of this association, usually occurring on fractured slickrock exposures, may have as little as 5% total vegetation cover and an upper canopy only 2 m tall.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This is a widely distributed association found in the Colorado Rockies east of the Continental Divide south into south-central New Mexico. On dry, rocky sites, this pinyon-juniper woodland association may include stands with very open tree canopies (5-10% cover) in cases where the total vegetation cover is less than 15%. These stands may be similar to open Cercocarpus montanus shrublands with scattered pinyon and juniper trees but is considered to be a variation of the woodland type because of the ecological values of the trees.

In northwestern New Mexico, the distributional ranges of Juniperus monosperma and Juniperus osteosperma overlap. This association does not occur within the range of Juniperus osteosperma within the transition zone between the southern Rocky Mountains to the Colorado Plateau. Some stands may be dominated by Pinus edulis without any Juniperus spp. These stands are separated from the similar ~Pinus edulis - Juniperus osteosperma / Cercocarpus montanus - Mixed Shrubs Woodland (CEGL005657)$$ by geographic range (east of the Continental Divide in Colorado).

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available

Floristics: This association is characterized by an open to moderately dense tree canopy (10-60% cover) dominated by a combination of Pinus edulis and Juniperus spp. The canopy averages 2-5 m tall, but some stands may be as tall as 10 m. Pinus edulis and Juniperus monosperma codominate in most stands, but sometimes one may be more prevalent than the other. Pinus edulis and Juniperus spp. are also present as smaller individuals in the shrub and field strata. The species of Juniperus varies with geography and elevation. Juniperus monosperma is common in north-central New Mexico and southern Colorado. Juniperus deppeana is common in southern New Mexico. Juniperus scopulorum is more common in higher elevation stands. Juniperus osteosperma is absent as it occurs outside its range. The total shrub cover may range from sparse to moderate. Cercocarpus montanus is the dominant shrub with 1-35% cover. It typically occurs as a short shrub <2 m tall but can be a tall shrub (2-5 m) on some sites. Other shrubs may be present, including Amelanchier spp., Artemisia bigelovii, Artemisia tridentata, Ephedra viridis, Chrysothamnus viscidiflorus, Gutierrezia sarothrae, Fendlera rupicola, Fraxinus anomala, Garrya ovata, Mahonia spp., Nolina microcarpa, Purshia stansburiana, Quercus gambelii (<5% cover), Quercus grisea, Rhus trilobata, Symphoricarpos oreophilus, or species of Yucca and Opuntia. Herbaceous cover is variable, ranging from sparse to moderately dense, and generally dominated by graminoids (>5% cover) with scattered forbs. Associated graminoids include Achnatherum hymenoides (= Oryzopsis hymenoides), Andropogon gerardii, Aristida purpurea, Bouteloua curtipendula, Bouteloua gracilis, Bouteloua hirsuta, Carex rossii, Hesperostipa comata, Koeleria macrantha, Leymus salinus (= Elymus salinus), Muhlenbergia pauciflora, Pascopyrum smithii, Pleuraphis jamesii, Poa fendleriana, Pseudoroegneria spicata, and Schizachyrium scoparium. Common forbs include species of Chamaesyce, Cryptantha, Eriogonum, Machaeranthera, Packera, Penstemon, Petradoria, Phlox, and Tetraneuris. Extremely open stands of this association occurring on exposed and fractured slickrock may have as little as 5% total vegetation cover and an upper canopy only 2 m tall. Biological soil crusts are patchy but may contribute up to 27% cover and are generally well-developed.

Dynamics:  Fires in this association are thought to be infrequent because Pinus edulis and Juniperus monosperma are killed or severely damaged by burns and do not resprout (Wright et al. 1979). Cercocarpus montanus, however, resprouts after burning and will re-establish relatively quickly (Pase and Lindenmuth 1971, Bradley et al. 1992). Conifers will re-establish more slowly. Stands occur in dry and often rocky habitats where fire frequency is low because of fuel discontinuity. When fire occurs, it will likely be severe because of greater fuel loads from decadent shrubs (Bradley et al. 1992).
Environmental Description:  This broadly defined woodland association on colluvial slopes, sandstone hogbacks, dry foothills and mesas. It can be found on any slope position (upper, middle, or lower), though lower slopes are the least common. Elevations range from 1472 to 2480 m (4830-8135 feet). Stands occur on gentle to steep (3-36°) slopes on all aspects. The soils are variable but generally shallow, poorly developed and skeletal, ranging from clayey marl to loamy sands. The unvegetated surface is characterized by bedrock, large and small rocks, and/or bare soil. Litter has low cover. Parent materials are often sandstone or shale, but others are possible.
Geographic Range: This widespread woodland association is found foothills in the southern Rocky Mountains east of the Continental Divide in southern Colorado and New Mexico, extending east into the southwestern Great Plains the hills, canyons, escarpments and other breaks.

Nations: US

States/Provinces:  AZ, CO, NM, OK?


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.2 Cool Temperate Forest & Woodland Formation F008 1.B.2
Division 1.B.2.Nc Western North American Pinyon - Juniper Woodland & Scrub Division D010 1.B.2.Nc
Macrogroup 1.B.2.Nc.2 Two-needle Pinyon - One-seed Juniper Southern Rocky Mountain Woodland Macrogroup M897 1.B.2.Nc.2
Group 1.B.2.Nc.2.c Two-needle Pinyon - One-seed Juniper - Rocky Mountain Juniper Woodland Group G253 1.B.2.Nc.2.c
Alliance A3576 Two-needle Pinyon - One-seed Juniper Shrubby Woodland Alliance A3576 1.B.2.Nc.2.c
Association CEGL005649 Two-needle Pinyon - (One-seed Juniper, Alligator Juniper) / Alderleaf Mountain-mahogany - Mixed Shrubs Woodland CEGL005649 1.B.2.Nc.2.c
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: = Juniperus osteosperma - Pinus edulis / Amelanchier utahensis - Cercocarpus montanus Marlstone Barrens Plant Association (Baker 1983b)
= Juniperus osteosperma - Pinus edulis / Cercocarpus montanus - Peraphyllum ramosissimum Plant Association (Baker 1984a)
= Pinus edulis - Juniperus monosperma / Cercocarpus montanus / Andropogon gerardii Habitat Type (Kennedy 1983a)
= Pinus edulis - Juniperus monosperma / Cercocarpus montanus Habitat Type (Hess and Wasser 1982)
> Pinus edulis - Juniperus monosperma / Cercocarpus montanus Plant Association (Johnston 1987)
>< Pinus edulis - Juniperus osteosperma / Amelanchier utahensis - Cercocarpus montanus Plant Association (Johnston 1987)
> Pinus edulis - Juniperus osteosperma / Cercocarpus montanus Plant Association (Johnston 1987)
= Pinus edulis - Juniperus osteosperma / Cercocarpus montanus Plant Association (Vories 1974)
= Pinus edulis - Juniperus spp. / Cercocarpus montanus - Mixed Shrubs Woodland (Bradley et al. 1992a)
< Pinus edulis / Cercocarpus montanus (Stuever and Hayden 1997b)
= Pinus edulis / Cercocarpus montanus Plant Association (Larson and Moir 1987)
< Coronado Province Pinyon - Juniper Woodlands (Isaacson 1967)
< La Sal Province Pinyon - Juniper Woodlands (Isaacson 1967)
Concept Author(s): K.A. Schulz

Author of Description: K.A. Schulz, J. Drake and J. Coles

Acknowledgements: No Data Available

Version Date: 01-13-16
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