Lutz spruce / Field horsetail - Oakfern
Picea X lutzii / Equisetum arvense - Gymnocarpium dryopteris
n = 12
I.A.2. Open Needleleaf Forest
Ecosystem: Discharge Slope

Lutz spruce (Picea X lutzii) forest types are poorly documented in Alaska.  On Chugach National Forest, a somewhat similar type was described by DeVelice, et. al. (1999) (Lutz spruce Oakfern, PICLUT-GYMDRY) but with very little field horsetail representation.

Lutz spruce / field horsetail (Equisetum arvense) oakfern (Gymnocarpium dryopteris) plant communities are primarily located on the discharge slopes of terraced moraines, which are more common south of Clam Gulch.  One of the sites visited, however, is located near Mackey Lake, east of Soldotna, and two others are near the coast north of Nikiski.   This community occurs at the upper edge of the groundwater discharge zone, and often does not indicate a regulatory wetland.

A tall, moderately open, forest tops a lush herbaceous understory of horsetail, with an open oakfern component.  Bluejoint grass (Calamagrostis canadensiscan be common, though scattered, and Canadian burnet (Sanguisorba canadensis) is present.  Barclay's willow (Salix barclayi) may also be common, scattered, or absent.  

The organic horizon is generally thin, but at the site near Soldotna, it was thicker than 150 cm.  Either the water table is, or redoximorphic features are, always encountered in the soil profile, but frequently deeper than 30 cm (one foot).  The pH at one site was strongly acid (4.6).  This plant community does not always indicate wetland conditions; only five of 12 sites included in this analysis could be classified as regulatory wetlands.

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

    Soil Series n

Hydric Criteria Number

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   0.8 42.9 np
tall Betula papyrifera   0.6 1.7 FACU FACU, FAC+
medium Picea X lutzii   0.8 5.4 np
regeneration Picea X lutzii   0.7 2.9 np
regeneration Betula papyrifera   0.6 0.4 FACU FACU, FAC+
Salix1 barclayi   0.7 19.5 FAC FAC, FACW
Spiraea stevenii   0.7 0.4 FAC FAC
Vaccinium ovalifolium   0.6 0.6 FAC FACU*, FAC
Equisetum arvense 1.0 50.8 FAC* FAC*, FACW-
Gymnocarpium dryopteris   1.0 35.1 FACU UPL, FAC
Calamagrostis canadensis   0.9 10.8 FAC FAC, OBL
Sanguisorba canadensis 0.9 9.5 FACW FACW,
Streptopus amplexifolius   0.9 0.7 FAC UPL, OBL
Chamerion angustifolium   0.9 0.2 FACU FACU, FAC
Rubus pedatus 0.8 14.7 FAC* FACU*, FAC*
Orthilia secunda   0.8 3.0 FACU* UPL, FAC+
Trientalis europaea 0.8 1.3 FAC FAC*, FAC
Linnaea borealis 0.8 1.1 FACU FACU-, FAC
Lycopodium annotinum 0.7 1.5 FAC FACU*, FAC
Geranium erianthum 0.7 1.0 np
Rubus arcticus 0.7 0.5 FAC FAC
Valeriana capitata   0.6 4.1 FAC FAC
Equisetum sylvaticum 0.6 2.5 FACU FACU, FACW
Dryopteris expansa   0.6 1.3 FACU FACU, FACW
Moss 1.0 60.1
Lichen 0.9 0.4
Open water 0.6 0.4
np- not on the wetland indicator status list
1 Plant with known morphological 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 09:51