Print Report

A0744 Rhododendron catawbiense - Rhododendron carolinianum - Kalmia latifolia Shrub Bald Alliance

Type Concept Sentence: This alliance includes evergreen shrublands dominated by ericaceous species, most often Rhododendron catawbiense, Rhododendron carolinianum, or Kalmia latifolia occurring on steep, exposed slopes, ridges, and rock outcrops in the southern Appalachian Mountains.

Common (Translated Scientific) Name: Catawba Rosebay - Carolina Azalea - Mountain Laurel Shrub Bald Alliance

Colloquial Name: Catawba Rosebay - Carolina Azalea - Mountain Laurel Shrub Bald

Hierarchy Level:  Alliance

Type Concept: This alliance includes evergreen shrublands occurring in the southern Appalachian Mountains. These shrublands are dominated by evergreen ericaceous species, most often Rhododendron catawbiense, Rhododendron carolinianum, or Kalmia latifolia. Deciduous shrubs may be present and even locally dominant. Openings in the shrub stratum may contain sparse herbaceous cover, including Deschampsia flexuosa, Galax urceolata, Gaultheria procumbens, Goodyera pubescens, Melampyrum lineare, Mitchella repens, Pteridium aquilinum, Selaginella tortipila, and Zigadenus leimanthoides. Mosses and lichens are also typical in more open occurrences. This evergreen, sclerophyllous vegetation is of low stature (<0.5 m) and occurs at the highest elevations in the southern Appalachian Mountains on steep, exposed slopes, ridges, thin soils and rock outcrops. It is typically found at elevations over 1770 m (5800 feet) in northwestern North Carolina and eastern Tennessee.

Diagnostic Characteristics: Distinctive shrublands dominated primarily by Rhododendron catawbiense, Rhododendron carolinianum, or Kalmia latifolia, but with some examples dominated or codominated by Leiophyllum buxifolium, restricted to higher elevations in the Southern Appalachians.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Similar, but floristically different, ericaceous shrublands occur in the Mahoosuc Mountains of Maine (Fahey 1976).

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: These shrublands are dominated by low-statured (<0.5 m) evergreen ericaceous species, most often Rhododendron catawbiense, Rhododendron carolinianum, or Kalmia latifolia.

Floristics: These shrublands are dominated by low-statured (<0.5 m) evergreen ericaceous species, most often Rhododendron catawbiense, Rhododendron carolinianum, or Kalmia latifolia. Deciduous shrubs may be present and even locally dominant. The occurrence and relative abundance of associated shrub species vary with elevation and adjacent vegetation. Other shrubs include Clethra acuminata, Gaylussacia baccata, Leiophyllum buxifolium, Leucothoe recurva, Aronia melanocarpa, Pieris floribunda, Rhododendron maximum, Vaccinium corymbosum, Vaccinium corymbosum, Vaccinium simulatum, Vaccinium stamineum, and Viburnum nudum var. cassinoides. This alliance includes vegetation dominated by Leiophyllum buxifolium growing in dense mats with a krummholz structure, with significant areas of bare rock. These examples are at least 25% vegetated with at least 75% of the total shrub cover composed of Leiophyllum buxifolium. Openings in the shrub stratum may contain sparse herbaceous cover, including Deschampsia flexuosa, Galax urceolata, Gaultheria procumbens, Goodyera pubescens, Melampyrum lineare, Mitchella repens, Pteridium aquilinum, Selaginella tortipila, and Zigadenus leimanthoides. Mosses and lichens are also typical in more open occurrences.

Dynamics:  These shrublands are subject to extremes in moisture due to extreme cold, high precipitation, frequent fog, and desiccating winds in combination with shallow, nutrient-poor soils. Windfall, landslides, and small, localized lightning-caused fires are important in the establishment and maintenance of these shrublands. This community can result from secondary succession after fire or logging or can occur as a topo-edaphic climax on steep or exposed sites. This vegetation may result from primary succession or from secondary succession when lichens, mosses, and eventually shrubs invade rock exposed by landslides or catastrophic fires.
Environmental Description:  This alliance includes evergreen shrublands occurring on steep, exposed slopes, ridges, thin soils, and rock outcrops at the highest elevations in the southern Appalachian Mountains. It is typically found at elevations over 1770 m (5800 feet) in northwestern North Carolina and eastern Tennessee. These shrublands are subject to extremes in moisture due to extreme cold, high precipitation, frequent fog, and desiccating winds in combination with shallow, nutrient-poor soils.
Geographic Range: This alliance is found in the southern Appalachian Mountains from Virginia south to Georgia. Examples in the Cumberlands of Kentucky and Southern Blue Ridge and Ridge and Valley of Virginia are rare and of limited extent.

Nations: US

States/Provinces:  GA, KY, NC, SC?, TN, VA


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: GNR

Greasons: No Data Available
Type Name Database Code Classification Code
Class 2 Shrub & Herb Vegetation Class C02 2
Subclass 2.B Temperate & Boreal Grassland & Shrubland Subclass S18 2.B
Formation 2.B.2 Temperate Grassland & Shrubland Formation F012 2.B.2
Division 2.B.2.Nc Eastern North American Grassland & Shrubland Division D024 2.B.2.Nc
Macrogroup 2.B.2.Nc.1 Catawba Rosebay / Michaux''s Saxifrage - Flattened Oatgrass Felsic & Mafic Scrub & Grassland Macrogroup M506 2.B.2.Nc.1
Group 2.B.2.Nc.1.a Catawba Rosebay - Mountain Fetterbush - Mountain Alder Southern Appalachian Shrub Bald Group G658 2.B.2.Nc.1.a
Alliance A0744 Catawba Rosebay - Carolina Azalea - Mountain Laurel Shrub Bald Alliance A0744 2.B.2.Nc.1.a
Association CEGL003814 Mountain Laurel - Catawba Rosebay - (Black Huckleberry, Mountain Fetterbush, Highbush Blueberry) Shrubland CEGL003814 2.B.2.Nc.1.a
Association CEGL003816 Carolina Azalea Shrubland CEGL003816 2.B.2.Nc.1.a
Association CEGL003818 Catawba Rosebay Shrubland CEGL003818 2.B.2.Nc.1.a
Association CEGL003951 Sand-myrtle Dwarf-shrubland CEGL003951 2.B.2.Nc.1.a
Association CEGL004516 Catawba Rosebay - Mountain Fetterbush Shrubland CEGL004516 2.B.2.Nc.1.a
Association CEGL004819 Minniebush - (Southern Mountain Cranberry, Upland Highbush Blueberry, Highbush Blueberry) - American Mountain-ash Shrubland CEGL004819 2.B.2.Nc.1.a
Association CEGL007876 Carolina Azalea - Catawba Rosebay - Sand-myrtle Shrubland CEGL007876 2.B.2.Nc.1.a
Concept Lineage: Six (of 6) from A.744, one from A.1063.

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: ? Picea rubens/Leiophyllum buxifolium outcrop community (Wiser 1993)
? Picea rubens/Leiophyllum buxifolium outcrop community (Wiser et al. 1996)
>< IC4a. Heath Bald Shrubland (Allard 1990)
>< Oligotrophic Scrub (Rawinski 1992)
Concept Author(s): K.D. Patterson, in Faber-Langendoen et al. (2013)

Author of Description: M. Pyne

Acknowledgements: The work of S. Wiser, A. Risk, C. Newell, and R.H. Whittaker is gratefully acknowledged.

Version Date: 09-26-14
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