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Larix occidentalis / Vaccinium caespitosum Forest | Western Ecology Working Group of...
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Name: Larix occidentalis / Vaccinium caespitosum Forest Reference: Western Ecology Working Group of... Description: This small- to large-patch minor forested type occurs throughout the northern Rocky Mountains. Its presence is strongly associated with well-drained sites in frosty basins or benchlands where cold air accumulates. It is found at moderate elevations between 915 to 1220 m (3000-4000 feet) in the western portion of its distribution but occurs as high as 1525 m (5000 feet) on the Flathead and Kootenai national forests, and yet further to the east it may be found to 2195 m (7200 feet) in basins along the Continental Divide. These sites are postulated to experience frequent summer frost coupled with warm daily maximum temperatures; this factor combination is thought to be limiting to climax conifer species, which establish and grow slowly on these sites. Surface soils are mostly derived from alluvial and to lesser degree colluvial deposits, both gravelly and non-gravelly sandy loams to silts with acidic reaction (pH averaged 5.0 in Montana for comparable type). Sites with the above suite of characteristics are generally dominated by <i>Pinus contorta</i> in the overstory, but occasionally <i>Larix occidentalis</i> becomes abundantly established, the unique result of a plentiful local <i>Larix</i> cone crop and a stand-replacing disturbance (wildfire) and a non-serotinous local population of <i>Pinus contorta</i>. <i>Pseudotsuga menziesii</i> and <i>Pinus contorta</i> are present as a minor component of open canopies dominated by <i>Larix occidentalis</i>; <i>Abies lasiocarpa</i> and <i>Picea engelmannii</i> are present as depauperate specimens in the reproductive layers. Though short shrubs may be represented and even exhibit high constancy (e.g., <i>Amelanchier alnifolia, Lonicera utahensis, Spiraea betulifolia, Shepherdia canadensis, Juniperus communis</i>), it is the dwarf-shrub layer that dominates. Cover of the two indicators of the type, <i>Vaccinium caespitosum</i> and <i>Arctostaphylos uva-ursi</i>, varies markedly, from a few percent to nearly a continuous layer. Other dwarf-shrubs with a consistent presence and occasional abundance are <i>Linnaea borealis, Mahonia repens, Vaccinium scoparium</i>, and <i>Vaccinium myrtillus</i>. <i>Calamagrostis rubescens</i> consistently dominates the graminoid component, and frequently it fills the interstices between dwarf-shrubs to create a virtually unbroken layer. <i>Carex geyeri</i> and <i>Carex concinnoides</i> are also moderately constant within the type. Forbs are usually a negligible component with only <i>Arnica cordifolia, Orthilia secunda (= Pyrola secunda), Hieracium albiflorum</i>, and <i>Maianthemum racemosum</i> exhibiting moderate to high constancy.  Accession Code: VB.CC.31134.CEGL005882 Plot-observations of this Community Concept: 0
	Party Perspective according to: NatureServe (organization) Perspective from: 17-Nov-2014 to: 01-May-2019
	status: accepted This Community's Level: association This Community's Children: [none]		Names:   UID: ELEMENT_GLOBAL.2.728657 NatureServe Explorer   Translated: Western Larch / Dwarf Bilberry Forest   Scientific: Larix occidentalis / Vaccinium caespitosum Forest   Code: CEGL005882