Common (Translated Scientific) Name: Ponderosa Pine / Wax Currant Forest

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: These montane evergreen stands are common on the eastern side of the Continental Divide in Rocky Mountain National Park between 2200 and 2840 m (7215-9300 feet) elevation. They often occur on the southern flank of lateral moraines and on other dry, south-facing slopes at pitches that are moderate to somewhat steep (10-49%). Soils are rapidly drained loamy sands derived from granitic parent material. Exposed bedrock, boulders, and small rocks can make up 10-25% of the ground surface within the stand, and another 25-75% of the ground is covered in long needle litter and duff. Pinus ponderosa var. scopulorum forms an open canopy within this association. Trees reach between 10 and 20 m in height with areal coverage of 20-40%. In addition to Pinus ponderosa var. scopulorum, scattered individuals of Pseudotsuga menziesii can contribute up to 10% cover, and Pinus contorta var. latifolia, Pinus flexilis, and Juniperus scopulorum can be found in low concentrations. The association is defined by a consistent yet inconspicuous shrub layer dominated by Ribes cereum that covers only 20% of the surface area within the stand. The shrubs generally grow between 0.5-1 m tall and are dispersed throughout the stand. Several other shrub species can occur, but all with <5% cover. These species include Arctostaphylos uva-ursi, Ceanothus fendleri, Juniperus communis var. montana, Mahonia repens, Prunus virginiana var. melanocarpa, Purshia tridentata, and Rubus deliciosus. Herbaceous cover within the association can be variable. Some stands have up to 50% cover of dry montane graminoids such as Muhlenbergia montana and Carex rossii; other stands have only 10% herbaceous cover with a heavy litter layer blanketing the understory. Common forbs, nearly always found in trace amounts, include Antennaria spp., Artemisia ludoviciana, Draba spp., Eriogonum umbellatum var. umbellatum, Geranium caespitosum var. caespitosum, Potentilla fissa, Potentilla hippiana, Sedum lanceolatum ssp. lanceolatum, and Thermopsis divaricarpa. The invasive grasses Bromus tectorum and Poa pratensis have also been found in trace amounts within stands of this association.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This association is only known from Rocky Mountain National Park. It is not recognized as a separate habitat type in any U.S. Forest Service classifications. It was first classified as Xeric Foothill Woodland by Peet (1981) because of high constancy of Ribes cereum and Rubus deliciosus, although Purshia tridentata is frequently present but at lower cover. This association bears a remarkable resemblance to ~Pinus ponderosa var. scopulorum / Purshia tridentata Southern Rocky Mountain Woodland (CEGL005647)$$, which is relatively mesic with a shrub layer dominated by Purshia tridentata but has a similar mix of shrub species and could be treated within the variability of that type.

Similar NVC Types: No Data Available

note: No Data Available