Sweetgale Dwarf  birch / Water horsetail
Myrica gale Betula nana / Equisetum fluviatile  
n = 6
II.C.2.d. Open Low Shrub Birch-Ericaceous Shrub Bog.
Ecosystem: Relict Lakebed / Drainageway








This is a newly documented type for Alaska.  Two sweetgale (Myrica gale) dwarf birch (Betula nana) types have been documented, but both have other associates, and lack water horsetail (Equisetum fluviatile).  One, described by Seguin (1977, in Viereck, 1992) for Portage flats, has willow (Salix spp.) and bluej (Calamagrostis canadensis) as associates; the other, described by Rosenberg (1986) near the Kenai River, has shrubby cinquefoil (Dasiphora floribunda) and Labrador tea (Ledum palustre ssp. decumbens) as associates.  That community is nearly identical to the sweetgale shrubby cinquefoil type described elsewhere in this document.

Sweetgale dwarf birch / water horsetail is common on Kenai lowland wetlands, and can form extensive stands where it occurs.  The shrubs form a thicket, and are relatively tall, averaging between 70 cm and 1.2 m.  Frequently, standing water occupies microtopographic-low spots.  This community occurs on relict glacial lakebeds in broad zones of shallow groundwater discharge- near the base of terraces or along the margins of poorly defined drainageways.  

It typically occupies a zone between Barclay willow / bluejoint field horsetail (Salix barclayi / Calamagrostis canadensis - Equisetum arvense) discharge slopes above, and the strang-flark complex where sweetgale occurs with shrubby cinquefoil and a variety of sedges, below.  

Associated plants, typically found where micro-topography is more developed, are: bog blueberry (Vaccinium uliginosum), shrubby cinquefoil, field horsetail (Equisetum arvense) and crowberry (Empetrum nigrum).  In the typical stand, however, few associates are present besides the named dominants.  

The water table is shallow, averaging 14 cm; it is often at or above the surface. Peat averages 101 cm thick.  All six sites visited are jurisdictional wetlands.

Table 1. Frequency of occurrence and hydric status of soil series named at NRCS holes.  Bold type indicates soils on the NRCS Alaska hydric soils list. 

   Soil Series n

Hydric Criteria Number

STARICHKOF 3 1, 2B2, 3
1Proposed series, definitely hydric

 Table 2.  Summary of plant frequency and average cover for plants occurring in more than 50% of plots.

          Wetland Indicator Status


f  Average Cover   Alaska National
Shrubs/Stunted tree
stunted Picea X lutzii   0.7 3.3 np
Myrica gale1,2 1.0 30.0 OBL OBL
Betula nana 1.0 15.8 FAC FAC, OBL
Vaccinium uliginosum 1.0 1.7 FAC FACU+, FACW
Dasiphora floribunda   0.8 10.8 FAC FAC-, FACW
Empetrum nigrum 0.8 8.6 FAC FACU, FACW
Dwarf shrubs
Vaccinium oxycoccos 0.7 0.3 OBL OBL
Equisetum fluviatile 1.0 10.3 OBL OBL
Equisetum arvense 0.8 10.7 FAC* FAC*, FACW-
Eriophorum angustifolium   0.8 1.8 OBL OBL
Rubus chamaemorus 0.7 2.3 FACW FACW
Open water 0.8 11.5
np- not present on the wetland indicator status list
1,2 Plant with known morphological and physiological adaptation for occurrence in wetlands (USACE, 1987)


 Introduction and Key to Plant Communities  

Introduction and Key to Ecosystems

    Kenai Hydric Soils    Map Unit Summary    Methods    Glossary

Contact: Mike Gracz
Kenai Watershed Forum 
PO Box 15301
Fritz Creek, AK  99603
The Alaska Natural Heritage Program
Environment and Natural Resource Institute
University of Alaska, Anchorage
707 A Street, Suite 101
Anchorage, Alaska  99501

04 May 2007 09:50