Print Report
A3360 Picea mariana Krummholz Alliance
Type Concept Sentence: This alliance, known locally as "alpine krummholz" or "subalpine heath," is composed of severely wind-pruned, stunted Picea mariana, Abies balsamea, and boreal shrub thickets just above treeline in mountains, or on northern acidic rock outcrops, and at lower elevations where a cold microclimate is sustained by cold-air drainage. The vegetation ranges from dense thickets to patches interspersed with deciduous dwarf-shrubs, forbs, mosses, and lichens.
Common (Translated Scientific) Name: Black Spruce Krummholz Alliance
Colloquial Name: Black Spruce Krummholz
Hierarchy Level: Alliance
Type Concept: This alliance is composed of severely wind-pruned, stunted Picea mariana, Abies balsamea, and boreal heathland thickets bordering the treeline and true alpine vegetation. The vegetation ranges from dense thickets to patches interspersed with deciduous dwarf-shrubs, forbs, mosses, and lichens. The canopy is characterized by stunted Picea mariana and Abies balsamea, sometimes in association with Picea rubens, Betula papyrifera var. cordifolia, and Sorbus americana. Shrubs may form a distinct layer where stunted trees are scattered, or as distinct patches in association. Characteristic shrubs are ericaceous species such as Ledum groenlandicum, Kalmia angustifolia, Vaccinium vitis-idaea, Vaccinium uliginosum, Rhododendron canadense, as well as Empetrum nigrum and Sibbaldiopsis tridentata, and are of variable closure, but may be patchy and interspersed with expanses of bare or lichen-covered bedrock. Herbaceous species, such as Paronychia argyrocoma and Juncus trifidus, are usually confined to crevices. Pleurozium schreberi and Dicranum scoparium are characteristic mosses. This alliance occurs at high elevations, usually just above tree line, where cool temperatures and high winds prevail. Snow tends to accumulate in and around the stunted trees creating a protected environment. This alliance occurs in Maine, New Hampshire, Vermont, and New York. It is also likely to occur in Canada.
Diagnostic Characteristics: High-elevation, stunted thicket of boreal conifers and heaths in northern New England and adjacent Canada.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This vegetation bears a resemblance to spruce-fir forests occurring downslope, but is dominated by Picea mariana rather than Picea rubens.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Physiognomy of this alliance is variable, ranging from sparse woodland to shrubland to sparsely vegetated rock; many occurrences have patches of all three. The tree canopy is sparse, averaging less than 20%, and individuals are stunted. Most trees in this community actually fall into the "tall shrub" physiognomic form. Tall shrubs may be scattered, or form patches in somewhat protected areas. The dwarf-shrub layer is very well-developed and the dominant feature of the vegetation. Herbs are sparse. The bryoid layer is variable but is often extensive, with both bryophytes and lichens.
Floristics: The canopy is characterized by stunted Picea mariana and Abies balsamea, sometimes in association with Picea rubens, Betula papyrifera var. cordifolia (= Betula cordifolia), and Sorbus americana. Shrubs may form a distinct layer where stunted trees are scattered, or as distinct patches in association with conifer patches. Characteristic shrubs are ericaceous species such as Ledum groenlandicum, Kalmia angustifolia, Vaccinium vitis-idaea, Vaccinium uliginosum, Rhododendron canadense, as well as Empetrum nigrum, Sibbaldiopsis tridentata, Viburnum nudum var. cassinoides and are of variable closure, but may be patchy and interspersed with expanses of bare or lichen-covered bedrock. Herbaceous species, such as Paronychia argyrocoma (= var. albimontana) and Juncus trifidus, are usually confined to crevices. Other herbaceous associates can include Clintonia borealis, Cornus canadensis, Deschampsia flexuosa, Gaultheria hispidula, Maianthemum canadense, Mitella nuda, Solidago macrophylla, and Trientalis borealis. The bryoid layer is characterized by the mosses Dicranum scoparium, Hylocomium splendens, Leucobryum glaucum, Pleurozium schreberi, Polytrichum strictum, as well as lichens of the genera Cetraria and Cladonia.
Dynamics: Temperature and wind are the main limiting factors that structure the vegetation. Cold temperatures support this vegetation at lower elevations where it occurs at the base of talus slopes that receive cold-air drainage. In alpine settings, wind shear and cold temperatures limit the growth form of boreal conifers.
Environmental Description: This vegetation occurs on acidic bedrock on northern bedrock outcrops, upper ridges, and summits, ranging in elevation from 550 m (1800 feet) (in the north) to 1430 m (4700 feet). It also occurs at the base of talus slopes at lower elevations (215 m [700 feet]) where cold-air drainage sustains a microclimate that is significantly cooler than the surrounding setting. Soil development is restricted to crevices or sheltered areas, where shallow organic accumulation occurs over a thin mineral layer, with shallow peat accumulating in depressions. The organic horizon may be saturated by fog in spring and fall but dry in summer. Soils are shallow, stony, coarse gravels and sands over gravel, scree or bedrock.
Geographic Range: This alliance occurs at high elevations in the northern Appalachian Mountains, ranging to lower elevations in northern Maine and maritime Canada.
Nations: CA,US
States/Provinces: ME, NB, NH, NS?, NY, QC, VT
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.899484
Confidence Level: Moderate
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
| Type | Name | Database Code | Classification Code |
|---|---|---|---|
| Class | 4 Polar & High Montane Scrub, Grassland & Barrens Class | C04 | 4 |
| Subclass | 4.B Temperate to Polar Alpine & Tundra Vegetation Subclass | S12 | 4.B |
| Formation | 4.B.1 Temperate & Boreal Alpine Tundra Formation | F037 | 4.B.1 |
| Division | 4.B.1.Na Eastern North American Alpine Tundra Division | D042 | 4.B.1.Na |
| Macrogroup | 4.B.1.Na.1 Eastern North American Alpine Tundra Macrogroup | M131 | 4.B.1.Na.1 |
| Group | 4.B.1.Na.1.d <i>Vaccinium uliginosum - Diapensia lapponica - Carex bigelowii</i> Temperate Alpine Tundra Group | G909 | 4.B.1.Na.1.d |
| Alliance | A3360 Black Spruce Krummholz Alliance | A3360 | 4.B.1.Na.1.d |
| Association | CEGL006031 (Black Spruce, Balsam Fir) / Sheep Laurel - Bog Labrador-tea Dwarf-shrubland | CEGL006031 | 4.B.1.Na.1.d |
| Association | CEGL006038 Black Spruce - Balsam Fir / Shrubby Fivefingers Shrubland | CEGL006038 | 4.B.1.Na.1.d |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: < Alpine-heath (Vogelmann 1964)
< Boreal talus woodland (Thompson and Sorenson 2000)
< Cold-air talus woodland (Thompson and Sorenson 2000)
< Dwarf evergreen shrub (Whitney and Moeller 1982)
? Dwarf shrub heath (Bliss 1963)
< Krummholz (Bean 1926)
< Krummholz (Bliss 1963)
? Krummholz and heath-krummholz (Sperduto and Nichols 2004)
? Subalpine cold-air talus barren (Sperduto and Nichols 2004)
< Subalpine krummholz (Thompson and Sorenson 2000)
< Wind-shaped coastal krummholz (Bouchard and Hay 1976)
< Boreal talus woodland (Thompson and Sorenson 2000)
< Cold-air talus woodland (Thompson and Sorenson 2000)
< Dwarf evergreen shrub (Whitney and Moeller 1982)
? Dwarf shrub heath (Bliss 1963)
< Krummholz (Bean 1926)
< Krummholz (Bliss 1963)
? Krummholz and heath-krummholz (Sperduto and Nichols 2004)
? Subalpine cold-air talus barren (Sperduto and Nichols 2004)
< Subalpine krummholz (Thompson and Sorenson 2000)
< Wind-shaped coastal krummholz (Bouchard and Hay 1976)
- Bean, R. C. 1926. Some plants found on our Maine mountains. Maine Naturalist 6:33-37.
- Bliss, L. C. 1963. Alpine plant communities of the Presidential Range, New Hampshire. Ecology 44:678-697.
- Bouchard, A., and S. Hay. 1976. The vascular flora of the Gros Morne National Park Coastal Plain in Newfoundland. Rhodora 78:207-260.
- Faber-Langendoen, D., J. Drake, M. Hall, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, M. Russo, K. Schulz, L. Sneddon, K. Snow, and J. Teague. 2013-2019b. Screening alliances for induction into the U.S. National Vegetation Classification: Part 1 - Alliance concept review. NatureServe, Arlington, VA.
- Sperduto, D. D., and W. F. Nichols. 2004. Natural communities of New Hampshire: A guide and classification. New Hampshire Natural Heritage Bureau, DRED Division of Forests and Lands, Concord. 242 pp.
- Thompson, E. H., and E. R. Sorenson. 2000. Wetland, woodland, wildland: A guide to the natural communities of Vermont. The Nature Conservancy and the Vermont Department of Fish and Wildlife. University Press of New England, Hanover, NH. 456 pp.
- Vogelmann, H. W. 1964. Natural areas in Vermont. Some ecological sites of public importance. Agricultural Experiment Station of Vermont, Burlington, VT. 26 pp.
- Whitney, G. G., and R. E. Moeller. 1982. An analysis of the vegetation of Mt. Cardigan, New Hampshire: A rocky, subalpine New England summit. Bulletin of the Torrey Botanical Club 109:177-188.