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. 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. 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 55 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. 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. 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

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. Dwarf shrub, primarily Vaccinium vitis-idaea and Empetrum nigrum, also are usually abundant. 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 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 overstory. In many stands, Picea glauca and/or P. mariana saplings, small trees, and relic trees are common to well-represented.

Forest understory. 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. 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.