|Lutz spruce / Field horsetail – Bluejoint|
|Picea X lutzii / Equisetum arvense – Calamagrostis canadensis|
|n = 91|
|I.A.2 Open Needleleaf Forest|
|Ecosystem: Discharge Slope|
Although this is one of the most common wetland types on the Kenai lowlands, it is incompletely documented elsewhere in Alaska. DeVelice, et. al. (1999) describe both a Lutz spruce (Picea X lutzii) – bluejoint grass (Calamagrostis canadensis) and a Lutz spruce – field horsetail (Equisetum arvense) type. The Lutz spruce / field horsetail – bluejoint type described here has characteristics of both. The abundance of this community on the Kenai lowlands is probably due in part to spruce bark beetle (Dendroctonus rufipennis) mortality opening the spruce canopy, and an attendant increase in bluejoint cover.
Lutz spruce / field horsetail - bluejoint grass is widespread on toeslopes, mainly south of Ninilchik. It occurs on toeslopes adjacent to peatlands, and along terrace risers where groundwater discharge or dense till maintains a water table near the surface. It occurs less frequently on discharge slopes adjacent to (underfit) stream valley walls.
A tall, open canopy of spruce shades an understory of equally abundant tall bluejoint and field horsetail. Shieldfern (Dryopteris expansa), fireweed (Chamerion angustifolium) and woodland horsetail (Equisetum sylvaticum) are frequent associates. Trailing raspberry (Rubus pedatus) often forms discontinuous ground cover carpets.
Organic horizons are thin, although a few sites had layers more than 1 meter thick. The water table varies considerably, and the presence of shallow redoximorphic features in the soil is often the only indication that these locales are wet for some time during the growing season. pH varied widely from very strongly acid (4.5) to neutral (6.8), at the three sites where it was measured.
A Lutz spruce / field horsetail - bluejoint community does not always indicate that the soil criteria for classification as a jurisdictional wetland are met; one or more hydric soil indicators were found at only 54 of the 91 samples. Higher field horsetail cover generally indicates wetter conditions.
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.
|STARICHKOF||2||1, 2B2, 3|
|1Proposed series, definitely hydric|
|2Proposed series, hydric status unknown|
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||35.2||np|
|medium Picea X lutzii||0.8||8.2||np|
|regeneration Picea X lutzii||0.8||0.9||np|
|Vaccinium ovalifolium||0.6||1.2||FAC||FACU*, FAC
|Ribes triste||0.7||0.5||FAC||FAC. OBL|
|Calamagrostis canadensis||1.0||34.9||FAC||FAC, OBL|
|Equisetum arvense||1.0||36.8||FAC*||FAC*, FACW-
|Rubus pedatus||0.9||16.3||FAC*||FACU*, FAC*|
|Dryopteris expansa||0.9||9.6||FACU||FACU, FACW
|Chamerion angustifolium||0.9||7.5||FACU||FACU, FAC
|Equisetum sylvaticum||0.8||9.2||FACU||FACU, FACW
|Trientalis europaea||0.8||0.7||FAC||FAC*, FAC|
|Streptopus amplexifolius||0.8||1.6||FAC||UPL, OBL|
|Sanguisorba canadensis||0.8||8.9||FACW||FACW, FACW+|
|Linnaea borealis||0.7||1.5||FACU||FACU-, FAC
|Orthilia secunda||0.7||0.8||FACU*||UPL, FAC+|
|Gymnocarpium dryopteris||0.7||40.0||FACU||UPL, FAC|
|Lycopodium annotinum||0.6||2.0||FAC||FACU*, FAC|
|np- not on wetland indicator status
|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