Lutz spruce / Sitka alder / Field horsetail
Picea X lutzii / Alnus viridis ssp. sinuata / Equisetum arvense   
n = 34
I.A.2.  Open Needleleaf Forest
Ecosystem: Discharge Slope, Relict Glacial Lakebed 


Lutz spruce (Picea X lutzii) types are not described in either The Alaska Vegetation Classification (Viereck, et. al., 1992) or the Copper River classification (Boggs, 2000).  However, two types, the Sitka or white spruce (Picea sitchensis or P. glauca) / Sitka alder (Alnus viridis ssp. sinuata) communities are similar to the Kenai lowlands Lutz spruce / Sitka alder / field horsetail (Equisetum arvense) community.  On Chugach National Forest, DeVelice, et. al. (1999) describe both a Lutz spruce - field horsetail type and a Lutz spruce - Sitka alder type with field horsetail as a common associate.

Lutz spruce / Sitka alder / field horsetail is widespread and common south of Ninilchik.  It typically occurs where an upland discharges to a larger fen at a relict glacial lakebed or drainageway margin.  It was also found above riparian zones, or on relict lakebeds along a subtle slope break.  The open Lutz spruce canopy is now mostly killed by the spruce bark beetle (Dendroctonus rufipennis), though many of these stands were measured before the beetle population became epidemic. 

Typically, a tall open canopy of spruce shaded an open, tall alder shrub layer, with abundant horsetail groundcover.  Bluejoint (Calamagrostis canadensis) cover can be abundant, especially in more open stands or after significant bark beetle-caused mortality.  Trailing raspberry (Rubus pedatus) can form carpets; Canadian burnet (Sanguisorba canadensis) and twisted stalk (Streptopus amplexifolius) are common associates scattered amongst the horsetail.  

Nearly half the sites visited have organic horizons thick enough to qualify as organic soils (40 cm).  The water table is usually close to the surface, and pools are common.  The pH was strongly acid (5.3) at the one site measured.  This vegetation does not always indicate a wetland.  Five of the 34 plots failed to meet hydric soils criterion for a jurisdictional wetland; three others are close calls.

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

  Soil Series n

Hydric Criteria Number

STARICHKOF 5 1, 2B2, 3
NIKOLAI    1  1
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
tall Picea X lutzii 0.9 32.2 np
Alnus viridis ssp. sinuata 0.9 35.3 FAC FAC, FACW*
Spiraea stevenii 0.6 1.6 FAC FAC
Vaccinium ovalifolium 0.6 1.3 FAC FACU*, FAC
Equisetum arvense 0.9 55.9 FAC* FAC*, FACW-
Calamagrostis canadensis 0.8 19.9 FAC FAC, OBL
Rubus pedatus 0.7 13.0 FAC* FACU*, FAC*
Streptopus amplexifolius 0.6 0.8 FAC UPL, OBL
Trientalis europaea 0.6 0.7 FAC FAC*, FAC
Sanguisorba canadensis 0.6 8.5 FACW FACW,
Linnaea borealis 0.6 1.7 FACU FACU-, FAC
Chamerion angustifolium 0.6 2.3 FACU FACU, FAC
Dryopteris expansa 0.6 6.5 FACU FACU, FACW
Rubus arcticus 0.5 0.4 FAC FAC
Moss 0.9 44.2
Open water 0.6 2.1         
np- not present on the wetland indicator status list.


 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 09:51