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A2610 Toxicodendron diversilobum Scrub Alliance

Type Concept Sentence: This shrubland alliance is known from the southern, central and northern California coasts where Toxicodendron diversilobum is dominant or codominant.

Common (Translated Scientific) Name: Pacific Poison-oak Scrub Alliance

Colloquial Name: Pacific Poison-oak Scrub

Hierarchy Level:  Alliance

Type Concept: The vegetation of this shrubland alliance is characterized canopies dominated or codominated by Toxicodendron diversilobum which has >50% relative cover. Other shrub associates include Artemisia californica, Diplacus aurantiacus, Heteromeles arbutifolia, Keckiella cordifolia, Malosma laurina, Salvia leucophylla, Salvia mellifera, and Sambucus nigra. Scattered trees such as Juglans californica and Quercus agrifolia may be present. This shrubland alliance is known from the southern, central and northern California coasts. It occurs on somewhat steep to steep northwest- and northeast-facing slopes at low elevations between sea level and 719 m.

Diagnostic Characteristics: This shrubland alliance of the southern, central and northern California coasts has canopies with >50% relative cover of Toxicodendron diversilobum in association with other coastal shrubs.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This shrubland alliance is not currently well-known and the description is based on Sawyer et al. (2009).

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: This alliance is characterized by moderate cover of cold-deciduous shrubs <2 m in height with a sparse herbaceous layer. Scattered trees may be present.

Floristics: The vegetation is characterized canopies dominated or codominated by Toxicodendron diversilobum which has >50% relative cover. Other shrub associates include Artemisia californica, Diplacus aurantiacus, Heteromeles arbutifolia, Keckiella cordifolia, Malosma laurina, Salvia leucophylla, Salvia mellifera, and Sambucus nigra. Scattered trees such as Juglans californica and Quercus agrifolia may be present.

Dynamics:  Toxicodendron diversilobum sprouts vigorously from the root crown and from rhizomes after fire or other mechanical disturbance. Fire is not required for seed germination, but Keeley (1987) reported significant increase when seeds are exposed to charate. Seedlings originate from a seed bank and from fresh seed dispersed by birds. Dense thickets develop in areas when stands have been burned several times (Burcham 1974, Howard 1994).
Environmental Description:  This shrubland alliance occurs on somewhat steep to steep northwest- and northeast-facing slopes at low elevations between sea level and 719 m.
Geographic Range: This shrubland alliance is known from the southern, central and northern California coasts.

Nations: US

States/Provinces:  CA


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.1 Mediterranean Scrub & Grassland Formation F038 2.B.1
Division 2.B.1.Na Californian Scrub & Grassland Division D327 2.B.1.Na
Macrogroup 2.B.1.Na.2 Coastal Sagebrush - Black Sage - Coyotebrush Coastal Scrub Macrogroup M044 2.B.1.Na.2
Group 2.B.1.Na.2.c Californian North Coastal & Mesic Scrub Group G662 2.B.1.Na.2.c
Alliance A2610 Pacific Poison-oak Scrub Alliance A2610 2.B.1.Na.2.c
Association CEGL003473 Pacific Poison-oak - Coyotebrush - Thimbleberry Shrubland CEGL003473 2.B.1.Na.2.c
Association CEGL003736 Pacific Poison-oak - Coastal Sagebrush / Giant Wildrye Shrubland CEGL003736 2.B.1.Na.2.c
Association CEGL003745 Pacific Poison-oak - Orange Bush-monkeyflower Shrubland CEGL003745 2.B.1.Na.2.c
Concept Lineage: equivalent to A.2610

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: = Toxicodendron diversilobum (Poison oak scrub) Alliance (Sawyer et al. 2009) [37.940.00]
= Toxicodendron diversilobum Alliance (Poison oak scrub) (Buck-Diaz et al. 2012)
= Toxicodendron diversilobum Shrubland Alliance (CNPS 2017) [37.940.00]
< Coastal Sage-Chaparral Scrub (#37G00) (Holland 1986b)
Concept Author(s): J.O. Sawyer et al. (2009)

Author of Description: M.E. Hall

Acknowledgements: No Data Available

Version Date: 09-26-14
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