State 1
Spruce/Spruce Muskeg Sedge Open Forest

Community 1.1
Spruce/Spruce Muskeg Sedge Open Forest

Spruce/spruce muskeg sedge open forest consists of open to moderately open stands of spruce, with occasional woodland and moderately closed stands. Compared to Spruce/shrub birch woodland and Spruce/lichen woodland, herbs are abundant to very abundant in the ground layer of Spruce/spruce muskeg sedge open forest. Spruce/spruce muskeg sedge open forest represents late seral to potential vegetation on sites where it occurs. Sites that have remained undisturbed by wildfire for a long period generally have shallow permafrost and a perched water table. This type develops from Low shrub birch scrub and Spruce/shrub birch woodland. The Riparian-Wetland Status Classification varies from upland to Palustrine needle-leafed evergreen scrub-shrub and forested (Cowardin et al. 1979)

Forest overstory. Overstory composition varies from Picea mariana to mixed P. mariana and P. glauca. Tree canopy cover ranges from 10 to 50 percent. Trees are typically 15 to 35 feet (4.6 to 10.7 m) in height and 4.0 to 6.5 inches (10.0 to 16.5 cm) in diameter at ground level. Trees and small stands to 60 feet (18 m) in height occasionally occur. Basal area of trees varies considerably between stands, ranging from 30 to 125 feet2/acre (6.9 to 28.7 m2/ha) in 13 sample stands.

Forest understory. Carex lugens typically ranges from 15 to occasionally over 70 percent canopy cover. Other important herbs include Petasites frigidus, Equisetum spp., Rubus chamaemorus, Eriophorum brachyantherum, and Arctagrostis latifolia. Mosses and lichens are well-represented to more commonly abundant on the soil surface.

Like other spruce cover types, medium, low, and dwarf shrubs are also important in Spruce/spruce muskeg sedge open forest. Total shrub canopy cover ranges from around 30 to 70 percent or more. Betula glandulosa approximately 4.5 to 6 feet (0.4 to 1.8 m) in height and Ledum spp. and Vaccinium uliginosum 2 to 3.5 feet (0.6 to 1.1 m) in height are the most important shrubs. In most stands, Salix planifolia also is a common medium shrub. S. glauca and other tall willows are common to well-represented in many stands. Common low shrubs include V. vitis-idaea, Empetrum nigrum, Arctostaphylos rubra, and S. myrtillifolia.

State 2
Low Shrub Birch Scrub

Community 2.1
Low Shrub Birch Scrub

Spruce/shrub birch woodland consists of woodland to occasionally moderately open stands of spruce. Distribution and extent: river corridor and uplands; one of the most extensive and widely distributed cover types in the survey area Elevation: 1,850 to 3,000 feet (564 to 914 m) Landforms: nearly level stream terraces; nearly level to strongly sloping lacustrine terraces; and moderately steep to steep hill slopes, escarpments, and alluvial fans Principal soils: all mineral soils on stream terraces and uplands in the survey area; organic mat thickness ranges from 0 to 10 inches (0 to 25 cm) Spruce/shrub birch woodland is best described as mid to late seral. This type develops on a wide variety of sites following fire, either from Low shrub birch scrub or Low shrub birch/lichen scrub. On sandy and gravelly soils on stream terraces, outwash plains, and strandline deposits, and other sites with a short fire return interval, Spruce/shrub birch woodland is probably the potential. Elsewhere, continued succession may lead to Spruce/spruce muskeg sedge open forest and possibly Black spruce/closed sheath cottongrass woodland. Riparian-Wetland Status Classification: almost always upland; occasionally Palustrine needle-leafed evergreen scrub-shrub and forested (Cowardin et al. 1979)

Forest overstory. Overstory composition varies from Picea glauca to mixed P. glauca and P. mariana. Tree canopy cover ranges from 10 to 55 percent. Trees are typically 15 to 35 feet (4.6 to 10.7 m) in height and 4 to 6.5 inches (10 to 16.5 cm) in diameter at ground level. Trees and small stands to 60 feet (18.3 m) in height occasionally occur. Basal area of trees varies considerably between stands, ranging from 23 to 130 feet2/acre (5.3 to 29.8 m2/ha) in 18 sample stands. Snags and charred boles and downfall are well-represented in burned stands.

Forest understory. The understory is dominated by abundant to very abundant medium, low, and dwarf shrubs. There are usually two relatively distinct shrub layers. The upper layer is approximately 4.5 to 6 feet ( 1.4 to 1.8 m) in height. The overall dominant medium shrub is Betula glandulosa; however, Salix planifolia is common in most stands. S. glauca and other tall willows are common to well-represented in many stands. The lower shrub layer is composed of a number of low and dwarf ericaceous shrub 0.5 to 3.5 feet (0.2 to 1.1 m) in height. Common to abundant species include Ledum spp., Vaccinium uliginosum, V. vitis-idaea, Empetrum nigrum, and Arctostaphylos rubra. Total shrub canopy cover ranges from around 45 to 90 percent or more.

Herbs generally are of minor importance in Spruce/shrub birch woodland. Commonly occurring species include Petasites frigidus, Arctagrostis latifolia, Equisetum spp., Rubus chamaemorus, and Carex lugens. Mosses and lichens on the ground surface range from sparse, scattered patches to nearly continuous, luxuriant cover, depending on fire history and stand age.

State 3
Low Shrub Birch Scrub

Community 3.1
Low Shrub Birch Scrub

Low shrub birch scrub consists of moderately open to closed stands of medium and low shrubs dominated by Betula glandulosa, Ledum spp., and Vaccinium uliginosum. Distribution and extent: widely distributed throughout the uplands; extensive Elevation: 1,900 to 3,500 feet (579 to 1,067 m) Landforms: primarily level to moderately steep stream terraces, lacustrine terraces, and hill slopes; steep mountain slopes; all aspects Principal soils: various (This type occurs on most mineral upland and stream terrace soils in the area and occasionally on organic soils.) Depth to permafrost: permafrost usually absent; where present, ranges from 0 to 50 inches (0 to 127 cm) or more below the mineral surface. Depth to seasonally high water table: usually greater than 60 inches (greater than 152 cm); many stands with water table at 0 to 40 inches (0 to 102 cm) or deeper In most places, Low shrub birch scrub appears to be an early, post-fire seral stage leading to Spruce/shrub birch woodland or Spruce/spruce muskeg sedge open forest. Most stands have common to well-represented scattered trees and unburned woodland to reseed the stand, and Picea glauca and P. mariana seedlings and saplings are common. At higher elevations and on steep slopes, seed trees and seedlings are generally absent to uncommon, suggesting that progression toward the woodland stages in these stands may take a long time. Above about 2,700 feet (823 m), Low shrub birch scrub, where present, is probably the potential vegetation. The Carex lugens understory phase described above appears to be a condition associated with crown fires in which the woodland understory was essentially unburned or only lightly burned. These are the stands which more than likely have permafrost and a water table present in the soil profile. Riparian-Wetland Status Classification: usually upland; occasionally Palustrine broad-leaved deciduous scrub-shrub, saturated, mineral and organic (Cowardin et al. 1979)

Forest understory. Dwarf shrub, primarily Vaccinium vitis-idaea and Empetrum nigrum, also are usually abundant. B. glandulosa is typically 4.5 to 7 feet (1.4 to 2.1 m) in height and forms an irregular, broken upper shrub layer. Other shrubs are usually about 3 feet (0.9 m) in height or less and fill in the spaces between and below the birch. In many stands, Picea glauca and/or P. mariana saplings, small trees, and relic trees are common to well-represented. Canopy cover of the upper shrub layer ranges from 25 to 70 percent. Total shrub canopy cover is usually between 50 and 90 percent.

In most stands, the herb layer is sparse to open. The number of different herb species is usually fairly high; however, no species are particularly abundant. Important herbs include Equisetum spp., Petasites frigidus, Epilobium angustifolium, Arctagrostis latifolia, and Calamagrostis canadensis. A mosaic of feathermoss, lichen, and litter covers the ground surface. In some stands on more mesic sites, Carex lugens is abundant to very abundant, and lichen is usually considerably more abundant. Most stands show evidence of recent burns, and snags and woody litter are common to well-represented.