Natural Resources
Conservation Service

Ecological site F236XY157AK

Boreal Woodland Moist Loamy Plains

Last updated: 2/13/2024
Accessed: 11/21/2024

Home / Esd catalog / MLRA 236X / Ecological site F236XY157AK

USC

Metric

General information

Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.

MLRA notes

Major Land Resource Area (MLRA): 236X–Bristol Bay-Northern Alaska Peninsula Lowlands

The Bristol Bay-Northern Alaska Peninsula Lowland Major Land Resource Area (MLRA 236) is located in Western Alaska. This MLRA covers approximately 19,500 square miles and is defined by an expanse of nearly level to rolling lowlands, uplands and low to moderate hills bordered by long, mountain footslopes. Major rivers include the Egegik, Mulchatna, Naknek, Nushagak, and Wood River. MLRA 236 is in the zone of discontinuous permafrost. It is primarily in areas with finer textured soils on terraces, rolling uplands and footslopes. This MLRA was glaciated during the early to middle Pleistocene. Moraine and glaciofluvial deposits cover around sixty percent of the MLRA. Alluvium and coastal deposits make up a large portion of the remaining area (Kautz et al., 2012; USDA, 2006).

Climate patterns across this MLRA shift as one moves away from the coast. A maritime climate is prominent along the coast, while continental weather, commonly associated with Interior Alaska, is more influential inland. Across the MLRA, summers are general short and warm while winters are long and cold. Mean annual precipitation is 13 to 50 inches, with increased precipitation at higher elevations and areas away from the coast. Mean annual temperatures is between 30 and 36 degrees F (USDA, 2006).

The Bristol Bay-Northern Alaska Peninsula MLRA is principally undeveloped wilderness. Federally managed land includes parts of the Katmai and Aniakchak National Parks, and the Alaska Peninsula, Becharof, Togiak and Alaska Maritime National Wildlife Refuges. The MLRA is sparsely populated. Principal communities include Dillingham, Naknek, and King Salmon. Commercial fishing in Bristol Bay and the Bering Sea comprises a major part of economic activity in the MLRA. Other land uses include subsistence activities (fishing, hunting, and gathering) and sport hunting and fishing (USDA, 2006).

Ecological site concept

This boreal ecological site is on convex to linear slopes on drift plain talfs, comprised of mineral materials transported by glacier. Site elevation is 20 to 920 feet above sea level. Slopes are nearly level to gentle (0 – 5 percent). Soil hydrology, fertility, and a fire regime shape the vegetation on this site. A deep water table likely discourages recruitment of upland species. Soil development is weak, negatives affecting plant recruitment and growth.

The reference state supports three communities. The reference plant community is characterized as a white spruce woodland (Viereck et al., 1992). It is composed of a white spruce canopy with an open understory of ericaceous shrubs, grasses, mosses and lichens. Two early communities are the result of a fire cycle comprised of often low-intensity burns.

Associated sites

R236XY109AK	Subarctic Low Scrub Peat Drainages R236XY109AK described organic depressions on drift plains. These are features on the plains described by this site.
F236XY115AK	Boreal Forest Loamy Moist Slopes F236XY115AK describes rises on drift plains. Rises have soils that do not support a water table, have aquic soil conditions or undergo cryoturbation. This differs from the soil associated with F236XY157AK and results in different vegetative communities.

R236XY109AK

Subarctic Low Scrub Peat Drainages

R236XY109AK described organic depressions on drift plains. These are features on the plains described by this site.

F236XY115AK

Boreal Forest Loamy Moist Slopes

F236XY115AK describes rises on drift plains. Rises have soils that do not support a water table, have aquic soil conditions or undergo cryoturbation. This differs from the soil associated with F236XY157AK and results in different vegetative communities.

Similar sites

F236XY115AK	Boreal Forest Loamy Moist Slopes Both sites are on drift plains. F236XY115AK is on rises, which are drier than the talf positions of this site. Site and soil conditions create a woodland in this site and a forest on F236XY115AK.

F236XY115AK

Boreal Forest Loamy Moist Slopes

Both sites are on drift plains. F236XY115AK is on rises, which are drier than the talf positions of this site. Site and soil conditions create a woodland in this site and a forest on F236XY115AK.

Table 1. Dominant plant species

Tree	(1) Picea glauca
Shrub	(1) Betula nana (2) Empetrum nigrum
Herbaceous	Not specified

Download full description

Physiographic features

This site is on linear to convex slopes of drift plain talfs. Elevation ranges from 20 to 920 feet above sea level. Slopes are nearly level to gentle (0 – 5 percent). This site is found at all aspects. Ponding and flooding do not typically occur. A deep (39 – 59 inches) water table is present year-round.

Table 2. Representative physiographic features

Geomorphic position, flats	(1) Talf
Landforms	(1) Plains > Plain
Runoff class	Negligible to low
Flooding frequency	None
Ponding duration	Very brief (4 to 48 hours)
Ponding frequency	None
Elevation	20 – 920 ft
Slope	5%
Water table depth	39 – 59 in
Aspect	W, NW, N, NE, E, SE, S, SW

Table 3. Representative physiographic features (actual ranges)

Runoff class	Negligible to low
Flooding frequency	None
Ponding duration	Very brief (4 to 48 hours)
Ponding frequency	None to rare
Elevation	980 ft
Slope	5%
Water table depth	11 – 59 in

Climatic features

The climate of this site reflects that of the MLRA, which is described as maritime polar (EPA, 2013). Temperatures are moderated by the nearby Bristol Bay and norther Pacific bodies of water. Annual precipitation ranges from 21 – 34 inches with approximately 40 percent occurring during the June-September growing season (PRISM, 2018).

Table 4. Representative climatic features

Frost-free period (characteristic range)	75-100 days
Freeze-free period (characteristic range)	65-90 days
Precipitation total (characteristic range)	21-34 in
Frost-free period (actual range)	75-100 days
Freeze-free period (actual range)	65-90 days
Precipitation total (actual range)	15-41 in
Frost-free period (average)	90 days
Freeze-free period (average)	75 days
Precipitation total (average)	29 in

Characteristic range

Actual range

Bar

Line

Figure 1. Monthly precipitation range

Characteristic range

Actual range

Bar

Line

Figure 2. Monthly minimum temperature range

Characteristic range

Actual range

Bar

Line

Figure 3. Monthly maximum temperature range

Bar

Line

Figure 4. Monthly average minimum and maximum temperature

Figure 5. Annual precipitation pattern

Figure 6. Annual average temperature pattern

Soil features

Soils are young and weakly developed Inceptisols (Soil Survey Staff, 2013). They are very deep and well drained. They support a cryic temperature regime and an udic moisture regime. Parent material is volcanic ash over loess and/or drift.

Soil characteristics affecting vegetation include hydrology, development and fertility. A deep water table is present between 39 and 59 inches throughout the year. This is too deep to favor obligate wetland species, but likely discourages recruitment of upland species. Soil development affects plant recruitment and growth. Recruitment and growth are likely slow on weakly developed soils like this one, evidenced by an ochric epipedon and a cambic horizon. However, the presence of volcanic ash and andic soil properties likely increase soil fertility, increasing growth rates and recruitment possibilities. Further information is needed to determine the roles that soil development and fertility play on the vegetation on this site.

Correlated soil components in MLRA 236: D36-Boreal woodland loamy eolian slopes, moist; Okstukuk

Table 5. Representative soil features

Parent material	(1) Loess (2) Drift
Surface texture	(1) Silt loam (2) Highly organic silt loam
Drainage class	Well drained
Permeability class	Moderate
Soil depth	60 in
Surface fragment cover <=3"	Not specified
Surface fragment cover >3"	Not specified
Available water capacity (0-10in)	1.6 – 2.5 in
Soil reaction (1:1 water) (0-10in)	3.6 – 5.7
Subsurface fragment volume <=3" (Depth not specified)	Not specified
Subsurface fragment volume >3" (Depth not specified)	Not specified

Table 6. Representative soil features (actual values)

Drainage class	Moderately well drained to well drained
Permeability class	Moderate
Soil depth	60 in
Surface fragment cover <=3"	Not specified
Surface fragment cover >3"	Not specified
Available water capacity (0-10in)	1.6 – 2.5 in
Soil reaction (1:1 water) (0-10in)	3.6 – 5.7
Subsurface fragment volume <=3" (Depth not specified)	Not specified
Subsurface fragment volume >3" (Depth not specified)	Not specified

Ecological dynamics

This site is on linear to convex slopes of drift plain talfs. Local site factors such as hydrology, soil factors and fire support three communities on this site. The reference plant community is a white spruce woodland.

Vegetation reflects the underlying soil. A deep water table and aquic soil conditions are present throughout the year. This is too deep to favor obligate wetland species, but likely discourages recruitment of upland species. It also likely limits the growth of white spruce, preventing a forest from developing. Wet soils also can mitigate the effects of fire. Volcanic ash and andic soil properties likely increase soil fertility beyond typical weakly developed soils with an ochric epipedon and a cambic horizon.

Fire is the major documented disturbance regime on this site. Fire is natural and typically is unmanaged. High-intensity and low-intensity fires affect the recovery of vegetation differently. The severity of a burn generally refers to the proportion of the surface organic mat and tree canopy consumed during a fire (Chapin et al., 2006). Fires in cooler and moister habitats tend to result in low-intensity burns, which is typical for this ecological site. A low intensity burn will result in a community similar to that of the reference plant community (1.1). High intensity burns occur less frequently. These fires burn the organic layer and kill most of the plant life. The post-fire community after an intense fire is very different from the reference plant community. The fire cycle is expected to be around 100 years on this site, based on tree ages and depth to charcoal in the soil.

Windthrow may contribute to keeping the forest canopy open and promoting plant diversity in the understory. Willows are slightly to moderately browsed by moose. This does not appear to affect the ecological processes of the site.

The information in this Ecological Dynamics section, including the state-and-transition model (STM), was developed based on current field data, professional experience, and a review of the scientific literature. As a result, all possible scenarios or plant species may not be included. Key indicator plant species, disturbances, and ecological processes are described to inform land management decisions.

State and transition model

More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective text

Ecosystem states

1. Reference State

State 1 submodel, plant communities

1.1. White spruce/black crowberry-dwarf birch

1.2. Quaking aspen-white spruce/black crowberry-bog blueberry/bluejoint grass

1.3. Quaking aspen/dwarf birch-marsh Labrador tea/bluejoint grass

1.1A	-	Fire.
1.2A	-	Fire recovery.
1.2B	-	Fire.
1.3A	-	Fire recovery.

State 1
Reference State

Figure 7. Typical area of the reference plant community.

The reference state supports three community phases, which are distinguished by the developed structure and dominance of the vegetation and by their ecological function and stability. The reference community phase is needleleaf woodland. The presence of each community is dictated temporally by fire. This report provides baseline inventory data for the vegetation in this ecological site. Future data collection is needed to provide further information about existing plant communities and the disturbance regimes that result in transitions from one community to another. Common and scientific names are from the USDA PLANTS database. Community phases are characterized by the Alaska Vegetation Classification System (Viereck et al., 1992).

Community 1.1
White spruce/black crowberry-dwarf birch

Figure 8. Typical area of community 1.1.

Figure 9. Frequency and canopy cover of plants in community 1.1.

The reference plant community is needleleaf woodland (Viereck et al., 1992) with an understory of low and dwarf shrubs and mosses. Major species include white spruce (Picea glauca), black crowberry (Empetrum nigrum), dwarf birch (Betula nana), spirea (Spiraea stevenii), lingonberry (Vaccinium vitis-idaea), bog blueberry (Vaccinium uliginosum), and bluejoint grass (Calamagrostis canadensis). Slightly wetter areas may support high concentrations of willow (Salix spp.). Individual or small clusters of birch trees (Betula spp.) may be present. A diverse moss community is common, and it may include various sphagnum mosses (Sphagnum spp.), polytrichum mosses (Polytrichum spp.), splendid feathermoss (Hylocomium splendens), and Schreber’s big redstem moss (Pleurozium schreberi). Lichens typically are in the ground cover. Other ground cover commonly includes herbaceous litter and woody litter.

Dominant plant species

white spruce (Picea glauca), tree
black crowberry (Empetrum nigrum), shrub
dwarf birch (Betula nana), shrub
beauverd spirea (Spiraea stevenii), shrub
lingonberry (Vaccinium vitis-idaea), shrub
bog blueberry (Vaccinium uliginosum), shrub
bluejoint (Calamagrostis canadensis), grass
splendid feather moss (Hylocomium splendens), other herbaceous
Schreber's big red stem moss (Pleurozium schreberi), other herbaceous
knights plume moss (Ptilium crista-castrensis), other herbaceous

Community 1.2
Quaking aspen-white spruce/black crowberry-bog blueberry/bluejoint grass

Figure 10. Typical area of community 1.2.

Figure 11. Frequency and canopy cover of plants in community 1.2.

The late fire community phase is a closed mixed forest that has an understory of low and dwarf shrubs. The tree canopy cover may vary greatly depending on the period since the last fire and the point in transition between the early fire community phase and the reference community phase. This community supports an overstory of quaking aspen (Populus tremuloides) and white spruce and an understory of bog blueberry, black crowberry, resin birch (Betula glandulosum), and bluejoint grass. Other species include spirea, various willows, Altai fescue, fireweed, stiff clubmoss, and field horsetail (Equisetum arvense). Mosses, particularly feathermosses, generally are in the ground cover, and lichens typically are a minor component. The ground cover may include woody litter and herbaceous litter. Some areas are bare soil.

Dominant plant species

quaking aspen (Populus tremuloides), tree
white spruce (Picea glauca), tree
bog blueberry (Vaccinium uliginosum), shrub
black crowberry (Empetrum nigrum), shrub
resin birch (Betula glandulosa), shrub
bluejoint (Calamagrostis canadensis), grass
fireweed (Chamerion angustifolium), other herbaceous
splendid feather moss (Hylocomium splendens), other herbaceous
Schreber's big red stem moss (Pleurozium schreberi), other herbaceous
knights plume moss (Ptilium crista-castrensis), other herbaceous

Community 1.3
Quaking aspen/dwarf birch-marsh Labrador tea/bluejoint grass

Figure 12. Typical area of community 1.3.

Figure 13. Frequency and canopy cover of plants in community 1.3.

The early fire community phase is open low scrubland that includes regenerative quaking aspen. Typically, this community consists of dwarf birch, marsh Labrador tea, bog blueberry, and halberd willow (Salix hastata) with regenerative quaking aspen throughout. Standing, dead white spruce trees are present. Other common species include bluejoint grass, sedges (Carex spp.), fireweed, and Nootka lupine (Lupinus nootkatensis). Mosses generally are in the ground cover, including polytrichum mosses (Polytrichum spp.). Other ground cover includes herbaceous litter and woody litter. Some areas are bare soil.

Dominant plant species

quaking aspen (Populus tremuloides), tree
dwarf birch (Betula nana), shrub
marsh Labrador tea (Ledum palustre ssp. decumbens), shrub
bog blueberry (Vaccinium uliginosum), shrub
bluejoint (Calamagrostis canadensis), grass
fireweed (Chamerion angustifolium), other herbaceous
polytrichum moss (Polytrichum piliferum), other herbaceous

Pathway 1.1A
Community 1.1 to 1.3

White spruce/black crowberry-dwarf birch

Quaking aspen/dwarf birch-marsh Labrador tea/bluejoint grass

A high intensity fire removes trees and taller shrubs and burns the organic soil layer. Increased light and exposed mineral soil are ideal for quaking aspen seedlings to colonize, with is highly competitive in burned areas (DeByle et al., 1987). Pockets of shrubs in wet spots are likely to escape fire damage and remain a propagation source via seeding or vegetative spread. Based on burn evidence in the soil, the fire cycle is hypothesized to repeat every 100 years.

Pathway 1.2A
Community 1.2 to 1.1

Quaking aspen-white spruce/black crowberry-bog blueberry/bluejoint grass

White spruce/black crowberry-dwarf birch

White spruce (Picea glauca) continues to grow and spread, eventually shading out quaking aspen (Lavertu et al. 1994; Howard, 1996). The shrub community diversifies. The time required for this transition likely depends on various factors, including the reproduction rate of white spruce seeds and the growth rate of shrubs and trees.

Pathway 1.2B
Community 1.2 to 1.3

Quaking aspen-white spruce/black crowberry-bog blueberry/bluejoint grass

Quaking aspen/dwarf birch-marsh Labrador tea/bluejoint grass

Fire can remove trees and shrubs. Fuel load is relatively low in community 1.2. Typical fire intensity and frequency are unknown in this community.

Pathway 1.3A
Community 1.3 to 1.2

Quaking aspen/dwarf birch-marsh Labrador tea/bluejoint grass

Quaking aspen-white spruce/black crowberry-bog blueberry/bluejoint grass

The post-fire community is comprised of fast-growing herbaceous species and extant individuals that did not burn. Quaking aspen continues to grow as white spruce seedlings appear. This transition rate depends on several site and plant factors, including the growth rate of quaking aspen, distance to a seed source for white spruce, and the reproduction and growth rates of pioneer and extant shrubs.

Additional community tables

Supporting information

Inventory data references

Modal points for Community 1.1
07AO00402
07AO02202
10TD14102
10TD11501
10TD11502
07SS03603

Modal points for community 1.2
10TD11503

Modal points for community 1.3
07AO002501
07AO002502

References

Viereck, L.A., C. T. Dyrness, A. R. Batten, and K. J. Wenzlick. 1992. The Alaska vegetation classification. U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station General Technical Report PNW-GTR-286..

Other references

Chapin, F. S., III; L. A. Viereck; P. Adams; K. Van Cleve; C. L. Fastie; R. A. Ott; D. Mann; and J. F. Johnstone. 2006. Chapter 7: Successional processes n the Alaskan boreal forest. In Alaska’s Changing Boreal Forest. F. Stuart Chapin and Mark W. Oswood, Institute of Arctic Biology; Keith van Cleve, Forest Soils Laboratory, University of Alaska, U.S. Department of Agriculture, Forest Service; Leslie A. Viereck, Forest Soils Laboratory, Institute of Northern Forestry; and David L. Verbyla, Department of Forest Sciences, University of Alaska, editors. Oxford University Press, New York, New York. Pages 100-116.

DeByle, N.V., W.C. Fischer, and C. Bevins. 1987. Wildfire occurrence in aspen stands in the interior western United States. Western Journal of Applied Forestry. Volume 2: 73-76.

Howard, Janet L. 1996. Populus tremuloides. In: Fire Effects Information System. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Available at https://www.fs.fed.us/database/feis/plants/tree/poptre/all.html. Accessed May 7, 2013.

Kautz, D.R., P. Taber, and S. Nield, editors. 2012. Land Resource Regions and Major Land Resource Areas of Alaska. United States Department of Agriculture, Natural Resources Conservation Service (USDA–NRCS).

Lavertu, D., Y. Mauffette, and Y. Bergeron. 1994. Effects of stand age and litter removal on the regeneration of Populus tremuloides. Journal of Vegetation Science. Volume 5: 561-568.

PRISM Climate Group. (PRISM) Oregon State University. https://prism.oregonstate.edu. Date created October 2018. Accessed 3 Mar 2023.

Scenarios Network for Alaska and Arctic Planning (SNAP).  Historical Monthly Temperature – 1km, 1901-2009. http://ckan.snap.uaf.edu/dataset/. Accessed 20 Mar 2023.

Scenarios Network for Alaska and Arctic Planning (SNAP).  Historical monthly and derived precipitation products downscaled from CRU TS data via the delta methods – 2km, 1901-2009.  http://ckan.snap.uaf.edu/dataset/. Accessed 20 Mar 2023.

Soil Survey Staff. 2013. Simplified Guide to Soil Taxonomy. USDA-Natural Resources Conservation Service, National Soil Survey Center, Lincoln, NE.

United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land Resource Regions and Major Land Resource Areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296.

US Environmental Protection Agency (EPA). Level III Ecoregions of the Conterminous United States. UP ESP Office of Research and Development. Corvallis, OR. http://edg.epa.gov/. Created 16 Apr 2013. Accessed 20 Mar 2023.

Contributors

Phil Barber
Michael Margo
Sue Tester
Kendra Moseley
Steph Schmit
Steff Shoemaker
Jamin Johanson

Approval

Kirt Walstad, 2/13/2024

Rangeland health reference sheet

Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.

Author(s)/participant(s)
Contact for lead author
Date	02/14/2024
Approved by	Kirt Walstad
Approval date
Composition (Indicators 10 and 12) based on	Annual Production

Indicators

Number and extent of rills:
Presence of water flow patterns:
Number and height of erosional pedestals or terracettes:
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Number of gullies and erosion associated with gullies:
Extent of wind scoured, blowouts and/or depositional areas:
Amount of litter movement (describe size and distance expected to travel):
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):

Dominant:

Sub-dominant:

Other:

Additional:
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Average percent litter cover (%) and depth ( in):
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
Perennial plant reproductive capability: