Community Field Guide
Scientific Name:
Picea engelmannii / Lysichiton americanus Forest
Common Name:
Engelmann spruce / skunk cabbage Forest
Community Description
Environment:
This association occurs in low-elevation valleys, from 2500 to 3000 feet, within a mountainous region west of the Continental Divide in the northern Rockies. In this region the ranges are oriented northwesterly to southeasterly, and alternate with broad, nearly level valleys. The valley floors often consist of sediments deposited in lakes during late Tertiary and early Quaternary periods. The climate is modified by the influence of Pacific maritime air masses which results in cooler summers, milder winters (but still cold), greater cloudiness and precipitation evenly distributed throughout the year. Heavy snows occur during the winters. This association is found in valley bottoms, on level sites with high water tables. Sites are typically adjacent to low-gradient, meandering streams or ponds. Soils are wet throughout the year, with standing water in soil depressions; the water table surface is usually found less than 50 cm below the ground surface. Organic matter content is high, and gleying is occasionally present. Exposed rocks are not present.
Vegetation:
This a moderately open, forested wetland association, dominated by the evergreen needle-leaved trees Picea engelmannii or Picea glauca, or a hybrid of the two. Other trees present may include the conifers Abies lasiocarpa, Pinus contorta or Pseudotsuga menziesii, but only Picea spp. are successful in dominating these wet sites. Small depressions with standing water are interspersed among the trees. The shrub layer is abundant and dominated by a mix of tall, broad-leaved deciduous species. These include Alnus incana, Betula occidentalis, and Cornus sericea. The low, creeping shrub Cornus canadensis is common as well. The perennial forb Lysichiton americanus is important in the lush herbaceous layer, growing on the edge of water and on moist microsites throughout the understory. Other common herbaceous species include the forb Galium triflorum, the fern Athyrium filix-femina, and the rhizomatous, perennial grass Cinna latifolia.
Range:
This association is confined to the Flathead Valley Section (M333B) of the Northern Rocky Mountains Province of Bailey (1995). Its presence corresponds roughly with the Inland Maritime climatic regime, but the driving variable of greatest importance is permanent soil saturation (spring flooding common).
Management:
Windthrow following timber harvest limits the potential for timber management in this type, as do concerns over easily compacted wet soils. A rise in the water table following timber harvest could interfere with forest regeneration (Hansen et al. 1995). Saturated soils are highly susceptible to soil compaction or disturbance by livestock or heavy machinery.
Global Rank: G2 State Rank: S2
Global Rank Comments:
This association, the wettest within the Picea engelmannii Series, has a naturally restricted, perhaps relictual, distribution. It occurs on permanently saturated soils of low elevations in the valleys of northwestern Montana (primarily in the vicinity of Flathead and Whitefish lakes). Only one stand has received protection; four stands, all high-quality, have been quantitatively sampled but anecdotal information places the number of known occurrences at approximately triple this number. It is undocumented what past impacts have been to the type; almost certainly there has been a reduction in the type, stands having been logged in the first generation of forest cutting and sites drained for agricultural production. The logistic difficulties associated with harvesting on permanently saturated soils has precluded cutting of several stands as has the fact that some stands are on public land and their uniqueness was recognized by trained silviculturists. This type remains under continuing threat of development and timber cutting (most remaining stands are on private land) but as these sites are unequivocal Jurisdictional Wetlands they are theoretically protected by law through section 404 of the Clean Water Act and the swamp-buster provision of the Food Security Act.
Community References
Identifier:
CEGL000412
Author:
M.S. Reid, Mod. 99-04-14 / J. Greenlee
Citations:
Bailey 1995, Hansen et al. 1991, Hansen et al. 1995
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This information is from the:
Montana Natural Heritage Program
Montana State Library--Natural Resource Information System
1515 East Sixth Ave., Helena, MT 59620-1800
406 444-3989
mtnhp.org
mtnhp@mt.gov
