State 1
Balsam poplar-white spruce/thinleaf alder open forest

Community 1.1
Balsam poplar-white spruce/thinleaf alder open forest

This plant community is the historic, potential natural community for this ecological site. Balsam poplar-white spruce/thinleaf alder open forest consists of open to moderately open stands of mixed Populus balsamifera and Picea glauca. Tree canopy cover generally ranges from around 30 to 60 percent. Occasional woodland stands (10-25 percent forest canopy cover) also occur. Tree heights and diameters vary widely in Balsam poplar-white spruce/thinleaf alder forest. Included are stands dominated by tall, medium diameter Populus balsamifera in which Picea glauca form a somewhat lower, secondary layer. At the other extreme are stands dominated by Picea glauca 45 to 65 feet (13.7 to 19.8 m) in height and 8 to 14 inches (20 to 36 cm) in diameter at breast height, in which the shorter, subdominant Populus balsamifera are beginning to die off in the stand. In all stands, Populus balsamifera trees tend to be poorly formed with broken, irregular, partially dead crowns. Tree basal area in two sample stands was 210 and 275 feet2/acre (48.2 and 63.1 m2/ha). The forest understory is characterized by a sparse to closed layer of Alnus tenuifolia 7 to 20 feet (2.1 to 6.1 m) in height. Alder canopy cover ranges from 15 to 85 percent. In general, alder canopy cover decreases as the forest canopy cover increases. Salix alaxensis, a tall shrub remnant from earlier successional stages, is common in some stands. Most stands have a sparse to moderately open low shrub layer. Important low shrubs include Rosa acicularis, Viburnum edule, Ribes spp., and Salix spp. The herb layer is highly variable in Balsam poplar-white spruce/thinleaf alder open forest. Herb canopy cover ranges from sparse to closed and includes a wide variety of low to tall grasses and forbs. Important herbs include Calamagrostis canadensis, Arctagrostis latifolia, Equisetum spp. Artemisia tilesii, Epilobium angustifolium, Aster sibiricus, and Hedysarum alpinum. Leaf litter and mulch cover most of the soil surface in most stands. Woody litter from beaver felled Populus balsamifera and decadent willows are well-represented to abundant in many stands.

Forest overstory. Balsam poplar/thinleaf alder open forest consists of woodland to moderately open stands of Populus balsamifera. Picea glauca is common in the overstory in many stands and is often well-represented as a secondary tree layer. Tree canopy cover generally ranges from 15 to 60 percent. Balsam poplar/thinleaf alder open forest includes mature stands with trees 35 to 65 feet (10.7 to 19.8 m) in height and 7 to 11 inches (18 to 28 cm) in diameter at breast height. Larger diameter trees are in many stands. Younger stands of shorter, smaller trees and advanced regeneration also are included. Tree basal area in mature stands ranges from 160 to 275 feet2/acre (36.7 to 63.1 m2/ha). In all stands, regardless of age, Populus balsamifera trees tend to be poorly formed with broken, irregular, partially dead crowns. Most trees show evidence of heart rot and decay.

Forest understory. The forest understory is characterized by a sparse to closed layer of Alnus tenuifolia 6 to 20 feet (1.8 to 6.1 m) in height. Alder canopy cover ranges from 15 to 85 percent. In general, alder canopy cover decreases as the forest canopy cover increases. Salix alaxensis, a tall shrub remnant from earlier successional stages, is common in some stands. Most stands have a sparse to moderately open low shrub layer. Important low shrubs include Rosa acicularis, Viburnum edule, Ribes spp., and Salix spp.

The herb layer is highly variable in Balsam poplar/thinleaf alder open forest. Herb canopy cover ranges from sparse to closed and includes a wide variety of low to tall grasses and forbs. Important herbs include Arctagrostis latifolia, Equisetum spp. Artemisia tilesii, Epilobium angustifolium, Aster sibiricus, and Hedysarum alpinum. Leaf litter and mulch cover most of the soil surface in most stands. Woody litter from beaver felled Populus balsamifera and decadent willows is well-represented to abundant in many stands.

State 2
Balsam poplar/thinleaf alder open forest

Community 2.1
Balsam poplar/thinleaf alder open forest

Balsam poplar/thinleaf alder open forest consists of woodland to moderately open stands of Populus balsamifera. Picea glauca is common in the overstory in many stands and is often well-represented as asecondary tree layer.

Forest overstory. Tree canopy cover generallyranges from 15 to 60 percent. Balsam poplar/thinleafalder open forest includes mature stands with trees 35to 65 feet (10.7 to 19.8 m) in height and 7 to 11inches (18 to 28 cm) in diameter at breast height.Larger diameter trees are in many stands. Younger stands of shorter, smaller trees and advancedregeneration also are included. Tree basal area in mature stands ranges from 160 to 275 feet2/acre
(36.7 to 63.1 m2/ha). In all stands, regardless of age, Populus balsamifera trees tend to be poorly formed with broken, irregular, partially dead crowns. Most
trees show evidence of heart rot and decay.
The forest understory is characterized by a sparse to closed layer of Alnus tenuifolia 6 to 20 feet (1.8 to 6.1 m) in height. Alder canopy cover ranges from 15 to 85 percent. In general, alder canopy cover decreases as the forest canopy cover increases. Salix alaxensis, a tall shrub remnant from earlier
successional stages, is common in some stands. Most stands have a sparse to moderately open low shrub layer. Important low shrubs include Rosa acicularis, Viburnum edule, Ribes spp., and Salix spp. The herb layer is highly variable in Balsam poplar/thinleaf alder open forest.

Forest understory. Herb canopy cover ranges from sparse to closed and includes a wide variety of low to tall grasses and forbs. Important
herbs include Arctagrostis latifolia, equisetum spp. Artemisia tilesii, Epilobium angustifolium, Aster sibiricus, and Hedysarum alpinum. Leaf litter and mulch cover most of the soil surface in most stands. Woody litter from beaver felled Populus balsamifera
and decadent willows is well-represented to abundant in many stands.

State 3
Tall thinleaf alder scrub

Community 3.1
Tall thinleaf alder scrub

Tall thinleaf alder scrub consists of occasionally open to closed alder 10 to 20 feet (3.0 to 6.1 m) in height. Lower layers include an open to moderately open low shrub layer in most stands and a moderately open to closed herb layer.

Forest understory. Canopy cover of the tall alder layer typically ranges from 55 to 90 percent, although more open stands are frequently encountered. This layer is dominated by Alnus tenuifolia, and Salix alaxensis is common in many stands. Canopy cover of the low shrub layer generally ranges from 20 to 50 percent. Important species include Salix barclayi, S. monticola, and Rosa acicularis. Potentilla fruticosa is common in some stands. Calamagrostis canadensis and Arctagrostis latifolia, which dominate the herb layer, are generally about as tall as and intermixed with the low shrub layer. Other important tall herbs include Epilobium latifolium and Artemisia tilesii. Equisetum spp. are abundant medium herbs in most stands. Herb canopy cover generally ranges from around 40 to more than 90 percent. Seedlings of Picea glauca and Populus balsamifera are common to well-represented in the herb layer in most stands. The ground surface is covered with leaf litter and grass mulch.

State 4
Tall thinleaf alder/ willow scrub

Community 4.1
Tall thinleaf alder/ willow scrub

Tall thinleaf alder-feltleaf willow scrub consists of moderately open to closed stands of mixed Alnus tenuifolia and Salix alaxensis 10 to 20 feet (3.0 to 6.1 m) in height. Lower layers include a sparse to occasionally open low shrub layer and a sparse to moderately open herb layer. Canopy cover of the Alnus tenuifolia-Salix alaxensis layer ranges from 25 to more than 90 percent. Low shrub canopy cover is usually fairly sparse, ranging from around 10 percent to occasionally as much as 25 percent. Important low shrubs include Salix barclayi, S. monticola, Potentilla fruticosa, and Rosa acicularis. The herb layer is dominated by Calamagrostis canadensis and Arctagrostis latifolia, which are generally as tall or taller than, and intermixed with, the low shrubs. Other important herbs include Epilobium angustifolium, Agropyron trachycaulum, Artemisia tilesii, Polemonium acutiflorum, Equisetum spp., Aster sibiricus, and Hedysarum alpinum. Seedling and saplings of Populus balsamifera and Picea glauca are common in most stands. Leaf litter and herb mulch cover much of the soil surface. Setting Distribution and extent: river corridor throughout the alder zone; moderate extent Elevation: 1,900 to 2,400 feet (579 to 732 m) Landforms: level to nearly level flood plains; terrace height from 2 to 7 feet (0.6 to 2.1 m) Principal soils: Dackey and Kluna Depth to seasonally high water table: variable; ranges from less than 20 to greater than 60 inches (less than 51 to greater than 152 cm) Flooding frequency: frequent to occasional Successional Status Tall thinleaf alder-feltleaf willow scrub is an early seral stage of flood plain succession in the alder zone. It appears to develop directly from the Tall feltleaf willow and Tall feltleaf willow/alder scrub types. In Tall thinleaf alder-feltleaf willow scrub, Alnus tenuifolia and Salix alaxensis occupy approximately the same shrub canopy level. Over time, the alder will continue to increase in height and the willow will begin to die out, leading to Tall thinleaf alder scrub. Seedlings and saplings of Populus balsamifera and Picea glauca are already present in the Tall thinleaf alder-feltleaf willow scrub stage.

State 5
Tall thinleaf alder-feltleaf willow scrub

Community 5.1
Tall thinleaf alder-feltleaf willow scrub

Tall thinleaf alder/willow scrub consists of open to closed stands of mixed Alnus tenuifolia 8 to 15 feet (2.4 to 4.6 m) in height, and somewhat shorter Salix spp., with an open to moderately closed herb layer below. Canopy cover of the alder/willow layer ranges from 25 to more than 90 percent. Important willows include Salix barclayi, S. planifolia, and S. monticola. In most stands, Potentilla fruticosa and Rosa acicularis are common low shrubs, and seedlings and saplings of Populus balsamifera and Picea glauca are common. Calamagrostis canadensis, Arctagrostis latifolia, and other tall and medium herbs dominate the herb layer. Other important herbs include Equisetum spp., Epilobium angustifolium, Artemisia tilesii, Aster sibiricus, Hedysarum alpinum, Poa spp., and Rubus arcticus. In depressions and other wet microsites, Carex aquatilis often is well-represented to abundant. Leaf litter and herb mulch cover much of the soil surface. Setting Distribution and extent: river corridor throughout the alder zone; moderate extent Elevation: 1,900 to 2,400 feet (579 to 732 m) Landforms: level to nearly level point bars on flood plains; range in terrace height—generally from 2 to 4 feet (0.6 to 1.2 m) Principal soils: Dackey Depth to seasonally high water table: variable; ranges from less than 20 to greater than 60 inches (less than 51 to greater than 152 cm) Flooding frequency: occasional to frequent in many places Successional Status Tall thinleaf alder/willow scrub is an early seral stage of flood plain succession in the alder zone. It appears to develop directly from Low willow/herb scrub. Over time, the alder will continue to increase in height and relative canopy cover and the willow will decease in abundance, leading to Tall thinleaf alder scrub. Seedlings and saplings of Populus balsamifera and Picea glauca are already present in Tall thinleaf alder-willow scrub.

State 6
Tall feltleaf willow scrub

Community 6.1
Tall feltleaf willow scrub

Tall feltleaf willow scrub consists of open to moderately closed willow 7 to 15 feet (2.1 to 4.6 m) in height. Lower layers include a sparse to moderately closed low willow layer and an open to moderately closed herb layer. The tall willow is composed entirely of Salix alaxensis—canopy cover ranges from 25 to 70 percent. The low shrub layer ranges from 10 to 70 percent canopy cover and is composed primarily of S. barclayi and S. planifolia. Potentilla fruticosa and Vaccinium uliginosum are present in most stands, but other shrubs are generally of minor importance. The composition and abundance of the herb layer is variable, depending on stand location relative to the river channel and the frequency and duration of flooding. Herb cover ranges from 30 to 60 percent in most stands. Important herbs include Calamagrostis canadensis, Equisetum spp., Epilobium angustifolium, Hedysarum alpinum, Parnassia palustris, and Rubus arcticus. Leaf litter, woody debris, and small patches of moss cover most of the soil surface. Picea glauca and Populus balsamifera seedlings are occasional to common in many stands. Setting Distribution and extent: river corridor throughout the survey area; minor extent Elevation: 1,900 to 2,900 feet (579 to 884 m) Landforms: level flood plains; frequently immediately adjacent to the river channel; terrace height is usually less than 4 feet (less than 1.2 m) Principal soils: Tangoe and Dackey Depth to seasonally high water table: variable; ranges from 10 to 60 inches (25 to 152 cm) Flooding frequency: frequent to occasional Successional Status Salix alaxensis is a rapidly growing pioneering species on flood plains, and well adapted to frequent flooding and siltation. This species also appears to be relatively short lived and intolerant of canopy competition. Tall feltleaf willow scrub is an early seral stage of flood plain succession in both the alder and willow zones. Within the willow zone, this cover type typically occurs as stands of small extent on gravelly and silty bars immediately adjacent to the channel. Within the alder zone, Tall feltleaf willow scrub along with Tall feltleaf willow/alder scrub occur spatially and successionally between Sparsely vegetated alluvium and the Thinleaf alder scrub cover types.

State 7
Low willow/hrb scrub

Community 7.1
Low willow/hrb scrub

Low willow/herb scrub consists of moderately open to closed willow 2 to 7 feet (0.6 to 2.1 m) in height with a moderately closed to closed herb layer. Low shrub canopy cover ranges from 40 to 95 percent. Dominant shrubs include Salix planifolia, S. barclayi, and often S. monticola. S. alaxensis forms an open tall shrub layer in some stands. Other low shrubs are relatively unimportant except for Potentilla fruticosa and Vaccinium uliginosum. In most stands, the herb layer is composed of a rich variety of species. Herb and dwarf shrub canopy cover is typically greater than 80 percent. Occasionally the herb layer is only sparse to open. Important herbs include Calamagrostis canadensis, Epilobium angustifolium, Equisetum spp., Mertensia paniculata, Polemonium acutiflorum, Swertia perennis, and often Carex aquatilis. Rubus arcticus and Salix reticulata are common dwarf shrubs in many stands. The ground surface is covered with feathermoss patches and herbaceous and woody litter. Setting Distribution and extent: river corridor throughout the survey area; primarily the Middle Fork, Main Stem north of Canyon Rapids, and the upper reaches of the North and South Branches; moderate extent Elevation: 1,950 to 2,900 feet (594 to 884 m) Landforms: level to occasionally moderately sloping flood plains and low stream terraces; terrace height usually less than about 4 feet (less than about 1.2 m) Principal soils: Dackey, cool; Tangoe; Swedna, high elevation; Swedna; and Ogtna Depth to seasonally high water table: variable; mostly 10 to 40 inches (25 to 102 cm) Flooding frequency: frequent to occasional Successional Status Low willow/herb scrub occurs from above treeline down into the forest zone, and successional status varies from potential to early seral vegetation depending on the site. Within the forest zone, most stands have uncommon to common Picea glauca and often Populus balsamifera seedlings, saplings, and small trees. With forest development, terrace height usually increases from channel migration and down-cutting. Flooding frequency decreases and the soils become better drained. Along the Middle Fork immediately below Dickey Lake, Low willow/herb scrub is potential vegetation or possibly seral to Low shrub birch scrub, which replaces the willow on stream terraces as terrace height increases and periodic flooding ceases. In many places, Low willow/herb scrub occurs in close proximity with, and is transitional to, Low willow/water sedge scrub. Flooding is less frequent and of shorter duration in Low willow/herb scrub compared with Low willow/water sedge scrub. Also, surface ponding is less prevalent in Low willow/herb scrub.

State 8
Sparsely vegetated alluvium

Community 8.1
Sparsely vegetated alluvium

Sparsely vegetated alluvium consists of sparse stands of pioneering species on areas of recently deposited or exposed alluvium. Vegetative cover in these stands is generally low, ranging from less than 20 percent to 45 percent, or occasionally more. A wide variety of plant species in various combinations are in these stands. Common species on areas of Sparsely vegetated alluvium are listed in the Species Summary List. Sparsely vegetated alluvium is a pioneering stage of flood plain succession in both the willow and alder zones. All species in the Sparsely vegetated alluvium type appear to share several key adaptive traits—the ability to rapidly invade disturbed sites and exposed alluvium, and the ability to tolerate annual flooding and repeated siltation. Many of these pioneering species are dominants in later stages of vegetative progression. Examples include Salix alaxensis, Alnus tenuifolia, Populus balsamifera, and Picea glauca. Others are apparently intolerant of competition and soon become rare or absent as vegetation development progresses. Examples include Epilobium latifolium, Achillea millefolium, Fragaria virginiana, and Erigeron spp. Wetland Status Classification: Palustrine vegetated unconsolidated shore, Palustrine persistent emergent, Palustrine broad-leaved deciduous scrub-shrub (Cowardin et al. 1979); water regime ranges from temporarily to intermittently flooded; soils are mineral; usually riparian