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G209 Pinus flexilis - Juniperus scopulorum Rocky Mountain Foothill Woodland Group
Type Concept Sentence: This foothill woodland group is found on rocky sites in the Rocky Mountains from southern Alberta to central Colorado, including escarpments and low hills across Wyoming and the western Great Plains, and is characterized by an open-tree canopy or patchy woodland that is dominated by either Pinus flexilis, Juniperus osteosperma, or Juniperus scopulorum.
Common (Translated Scientific) Name: Limber Pine - Rocky Mountain Juniper Rocky Mountain Foothill Woodland Group
Colloquial Name: Rocky Mountain Foothill-Rock Outcrop Limber Pine - Juniper Woodland
Hierarchy Level: Group
Type Concept: This group occurs in foothills and may extend into lower montane zones in the Rocky Mountains from southern Alberta and northern Montana south to central Colorado and on escarpments across Wyoming extending out into the western Great Plains. Elevation ranges from 1000-2400 m. These are rock outcrop, escarpment and patchy woodlands, occurring generally below continuous forests of Pseudotsuga menziesii or Pinus ponderosa. Climatologically, the region is semi-arid and has a continental regime of hot summers and cold winters. Precipitation patterns are variable, but snow is common in winter, and spring rains are an important contributor. These woodlands are restricted to shallow soils and fractured bedrock derived from a variety of parent material, including limestone, sandstone, dolomite, granite, and colluvium. An unusual plant association in Idaho occurs on relatively unweathered mafic lava flows, where it occurs in mesic pockets within the fractured lava. In all cases, soils have a high rock component (typically over 50% cover) and are coarse- to fine-textured, often gravelly and calcareous. Slopes are typically moderately steep to steep. At higher elevations, it is limited to the most xeric aspects on rock outcrops, and at lower elevations to the relatively mesic north aspects. Fire is infrequent and spotty because the rocky substrates prevent development of a continuous vegetation canopy needed to spread. Vegetation is characterized by an open-tree canopy or patchy woodland that is dominated by either Pinus flexilis, Juniperus osteosperma, or Juniperus scopulorum. This group generally occurs outside of the range of Pinus edulis, which is not present. A sparse to moderately dense short-shrub layer, if present, may include a variety of shrubs, such as Artemisia nova, Artemisia tridentata, Cercocarpus ledifolius, Cercocarpus montanus, Ericameria nauseosa, Juniperus horizontalis, Purshia tridentata, or Rhus trilobata. Herbaceous layers are generally sparse, but range to moderately dense, and are typically dominated by perennial graminoids such as Bouteloua gracilis, Hesperostipa comata, Koeleria macrantha, Piptatheropsis micrantha, Poa secunda, or Pseudoroegneria spicata. Within this group, there may be small patches of grassland or shrubland composed of some of the above species.
Diagnostic Characteristics: Patchy woodlands found on rock outcrops and escarpments at foothill elevations along the eastern Rocky Mountains Front out into the western Great Plains. Dominant and characteristic species are Pinus flexilis, Juniperus osteosperma, or Juniperus scopulorum. Understory diagnostic species include both widespread Interior West species such as Artemisia nova, Artemisia tridentata, Cercocarpus ledifolius, Cercocarpus montanus, Ericameria nauseosa, Purshia tridentata, or Pseudoroegneria spicata and primarily Great Plains species such as Bouteloua gracilis, Koeleria macrantha, or Schizachyrium scoparium. Floristically these are more related to the Great Plains than to the main Rocky Mountains. High winds, cold winters, and fractured rock substrates are limiting ecological factors influencing the species composition. This group is somewhat analogous to pinyon-juniper woodlands, but pinyon pines are not present this far north, and limber pine is more tolerant of the high winds generally found east of the Continental Divide out in the northwestern Great Plains.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: How to treat Pinus flexilis in the Rocky Mountains is still somewhat uncertain. For now, we have kept three groups which have limber pine as a component. The group described here is composed predominantly of limber pine or juniper that is elevationally below the zone of continuous lower montane forests found in the main Rocky Mountain cordillera. The associations placed in this group are restricted to foothill settings on rock outcrops, or to escarpments in the Great Plains. Associations extending from the foothill zone into the subalpine, such as ~Pinus flexilis / Arctostaphylos uva-ursi Woodland (CEGL000802)$$, are included in ~Rocky Mountain Subalpine-Montane Limber Pine - Bristlecone Pine Woodland Group (G221)$$. Additionally, there are Juniperus osteosperma-dominated stands included in this group from the Pryor, Big Horn, and Laramie mountain ranges because these stands are significantly disjunct from the main distribution of Juniperus osteosperma in the Colorado Plateau and Great Basin regions and have floristic similarities to the Great Plains. Finally, this foothill woodland group is relatively fine scale and closely related to ~Black Hills-Northwestern Great Plains Ponderosa Pine Forest & Woodland Group (G216)$$. These two groups could be combined into a single group and this original concept could be treated as an alliance of this larger Great Plains woodland group.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Patchy woodlands dominated by relatively short conifers (scrub woodlands). Undergrowth can be shrubby with typically broad-leaved deciduous shrubs, but sometimes microphyllous evergreen Artemisia or Purshia. Grasses are common, typically cool-season bunch grasses. Sometimes there is little to no undergrowth.
Floristics: This group is dominated by Pinus flexilis, Juniperus osteosperma, or Juniperus scopulorum. Pinus edulis is not present. A sparse to moderately dense short-shrub layer, if present, may include a variety of shrubs, such as Artemisia nova, Artemisia tridentata, Cercocarpus ledifolius, Cercocarpus montanus, Ericameria nauseosa, Juniperus horizontalis, Purshia tridentata, Rhus trilobata, or Rosa woodsii. Herbaceous layers are generally sparse, but range to moderately dense, and are typically dominated by perennial graminoids such as Bouteloua gracilis, Hesperostipa comata, Koeleria macrantha, Leymus innovatus (in Alberta), Piptatheropsis micrantha (= Piptatherum micranthum), Poa secunda, Pseudoroegneria spicata, or Schizachyrium scoparium.
Dynamics: Fire is infrequent and spotty because the rocky substrates prevent development of a continuous vegetation canopy needed to spread.
Environmental Description: This group occurs in foothill and lower montane zones in the Rocky Mountains from southern Alberta and northern Montana south to central Colorado and on escarpments across Wyoming extending out into the western Great Plains. Elevation ranges from 1000-2400 m. It occurs generally below continuous forests of Pseudotsuga menziesii or Pinus ponderosa. Climatologically, the region is semi-arid and has a continental regime of hot summers and cold winters. High winds are a common feature found to the east of the Continental Divide and out in the Great Plains; limber pine is adapted to these winds with highly flexible branches which prevent breakage. Precipitation patterns are variable, but snow is common in winter, and spring rains are an important contributor. These woodlands are restricted to shallow soils and fractured bedrock derived from a variety of parent material, including limestone, sandstone, dolomite, granite, and colluvium. An unusual plant association in Idaho occurs on relatively unweathered mafic lava flows, where it occurs in mesic pockets within the fractured lava. In all cases, soils have a high rock component (typically over 50% cover) and are coarse- to fine-textured, often gravelly and calcareous. Slopes are typically moderately steep to steep.
Climate: Climatologically, the region is semi-arid and has a continental regime of hot summers and cold winters. High winds are a common feature found to the east of the Continental Divide and out in the Great Plains; limber pine is adapted to these winds with highly flexible branches which prevent breakage. Precipitation patterns are variable, but snow is common in winter, and spring rains are an important contributor.
Soil/substrate/hydrology: These woodlands are restricted to shallow soils and fractured bedrock derived from a variety of parent material, including limestone, sandstone, dolomite, granite, and colluvium. An unusual plant association in Idaho occurs on relatively unweathered mafic lava flows, where it occurs in mesic pockets within the fractured lava. In all cases, soils have a high rock component (typically over 50% cover) and are coarse- to fine-textured, often gravelly and calcareous. Slopes are typically moderately steep to steep.
Climate: Climatologically, the region is semi-arid and has a continental regime of hot summers and cold winters. High winds are a common feature found to the east of the Continental Divide and out in the Great Plains; limber pine is adapted to these winds with highly flexible branches which prevent breakage. Precipitation patterns are variable, but snow is common in winter, and spring rains are an important contributor.
Soil/substrate/hydrology: These woodlands are restricted to shallow soils and fractured bedrock derived from a variety of parent material, including limestone, sandstone, dolomite, granite, and colluvium. An unusual plant association in Idaho occurs on relatively unweathered mafic lava flows, where it occurs in mesic pockets within the fractured lava. In all cases, soils have a high rock component (typically over 50% cover) and are coarse- to fine-textured, often gravelly and calcareous. Slopes are typically moderately steep to steep.
Geographic Range: This group occurs in foothill and lower montane zones in the Rocky Mountains from southern Alberta and northern Montana south to central Colorado and on escarpments across Wyoming extending out into the western Great Plains. This group also occurs in southeastern Idaho, though it would not be common there.
Nations: CA,US
States/Provinces: AB, CO, ID, MT, ND, NE, SD, UT, WY
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.836637
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.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.d Limber Pine - Rocky Mountain Juniper Rocky Mountain Foothill Woodland Group | G209 | 1.B.2.Nb.2.d |
| Alliance | A3424 Limber Pine / Shrub Understory Central Rocky Mountain Woodland Alliance | A3424 | 1.B.2.Nb.2.d |
| Alliance | A3426 Rocky Mountain Juniper - Utah Juniper / Shrub Understory Central Rocky Mountain Woodland Alliance | A3426 | 1.B.2.Nb.2.d |
| Alliance | A3427 Rocky Mountain Juniper - Utah Juniper / Grass Understory Central Rocky Mountain Woodland Alliance | A3427 | 1.B.2.Nb.2.d |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: >< Limber Pine: 219 (Eyre 1980)
>< Rocky Mountain Juniper: 220 (Eyre 1980)
>< Rocky Mountain Juniper: 220 (Eyre 1980)
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