|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.
|STARICHKOF||5||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|
|tall Picea X lutzii||0.9||32.2||np|
|Alnus viridis ssp. sinuata||0.9||35.3||FAC||FAC, FACW*|
|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|
|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|
|np- not present on the wetland indicator status list.|
|Contact: Mike Gracz Kenai Watershed Forum PO Box 15301 Fritz Creek, AK 99603 907-235-2218||
Alaska Natural Heritage Program
and Natural Resource Institute
707 A Street, Suite 101
Anchorage, Alaska 99501
04 May 2007 09:51