Name:
Pinus albicaulis Woodland Alliance
Reference:
Western Ecology Working Group of...
Description:
This subalpine woodland alliance occurs locally on warm, dry, rocky, exposed sites in the mountains of the interior northwestern U.S. and the central and northern Rocky Mountains. Stands typically occur intermittently between the closed-canopy subalpine forestline and upper treeline, but may occur at lower elevations on rocky wind-swept ridges or where disturbance has reduced the cover of shade-tolerant tree species. Above the continuous forestline, these woodlands form patches separated by subalpine meadow or rock outcrops. Landforms include ridgetops, mountain slopes, and cirque headwalls and basins. Sites occur on all aspects, but are more typically south-facing. Substrates are generally rocky, shallow, coarse-textured soils. Woodlands included in this alliance have a sparse to moderate conifer tree canopy dominated or codominated by Pinus albicaulis. High-elevation stands are often stunted and may be only a few meters tall, and Pinus albicaulis may be the only tree in the canopy. Abies lasiocarpa is the most common associated tree species. Other associated tree species may include Pinus contorta, Pseudotsuga menziesii, Picea engelmannii, Tsuga mertensiana, and Pinus flexilis. There may be a sparse to moderate shrub layer consisting of tree regeneration and other woody species such as Arctostaphylos uva-ursi, Juniperus communis, Ribes spp., Shepherdia canadensis, Symphoricarpos oreophilus, and Vaccinium scoparium. The herbaceous layer ranges from absent on rocky sites to moderately dense cover of graminoids or forbs on more mesic sites. Associated herbaceous species include Achillea millefolium, Arnica spp., Calamagrostis rubescens, Carex geyeri, Cassiope mertensiana, Festuca idahoensis, Juncus parryi, Ligusticum grayi, Luzula glabrata var. hitchcockii, Phyllodoce empetriformis, Solidago multiradiata, and Xerophyllum tenax. Diagnostic of this alliance is the dominance of Pinus albicaulis in the open tree canopy.
Accession Code:
VB.CC.18753.PINUSALBICAULIS
Plot-observations of this Community Concept:
0
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