Natural Resources
Conservation Service
Major Land Resource Area 220X
Major Land Resource Area
Accessed: 04/24/2026
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Ecological sites
Major Land Resource Areas
Ecological site photos
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precipitation
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Precipitation
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Elevation
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Parent material origin
Parent material kind
Soil texture
Elevation typically between 0 and 3000 feet and vegetation representative of the subalpine and maritime life zones. This vegetation represents the Alexander Archipelago-Gulf of Alaska Coast Area (MLRA 220).
Elevation ≥ 3000 feet and vegetation representative of the alpine life zone. Alpine vegetation belongs to the Southern Alaska Coastal Mountains Area (MLRA 222).
Elevation between 1500 and 3000 feet and vegetation representative of the subalpine life zone.
Elevation typically between 0 and 1500 feet and vegetation representative of the maritime life zone.
Parent material is alluvium. Site associated with flood plains.
Parent material not alluvium and landform not associated with flood plain.
Hydrologic-driven (water influenced) communities
Not hydrologically driven (nor water influenced) communities
persistent water table throughout the growing season.
R220XY362AK – Subalpine Sedge Wet Flood Plain
R220XY362AK – Subalpine Sedge Wet Flood Plain
drier soils then above.
R220XY361AK – Subalpine Shrub Dry Flood Plain
R220XY361AK – Subalpine Shrub Dry Flood Plain
Soils are primarily organic material over bedrock.
Not as above. Parent material typically colluvium and/or residuum.
Dry soils, folistic.
F220XY338AK – Subalpine Forests Dry Organic Slopes
F220XY338AK – Subalpine Forests Dry Organic Slopes
Wet soils, histic.
F220XY204AK – Subalpine Forests Organic Wet Slopes
F220XY204AK – Subalpine Forests Organic Wet Slopes
Soil parent material is calcareous.
F220XY202AK – Subalpine Woodlands Gravelly Dry Slopes, Limestone
F220XY202AK – Subalpine Woodlands Gravelly Dry Slopes, Limestone
Soil parent material is not calcareous.
Site associated with avalanche chutes or soil creep. Alder is typically common and dominant.
Not as above.
Avalanche chutes.
R220XY349AK – Subalpine Scrub Gravelly Dry Chutes
R220XY349AK – Subalpine Scrub Gravelly Dry Chutes
Site associated with soil creep. Soils commonly have buried, mixed, and/or broken soil horizons. Soils with thick A-horizons are common.
R220XY358AK – Subalpine Scrub Gravelly Dry Slopes
R220XY358AK – Subalpine Scrub Gravelly Dry Slopes
Well- to moderately-well drained soils. Soils do not have a persistent water table at any depth during the growing season.
Wetter soils then above.
F220XY205AK – Subalpine Woodlands Gravelly Moist Slopes
F220XY205AK – Subalpine Woodlands Gravelly Moist Slopes
Occurs at the lowest band of subalpine vegetation. Trees more productive compared to es 350. Krummholz and alpine species less common.
F220XY200AK – Subalpine Forest Gravelly Dry Slopes
F220XY200AK – Subalpine Forest Gravelly Dry Slopes
Occurs at the highest band of subalpine vegetation. Trees less productive compared to es 200. Krummholz and alpine species more common.
F220XY350AK – Subalpine Woodland Gravelly Dry Slopes
F220XY350AK – Subalpine Woodland Gravelly Dry Slopes
Coastal hydrology controlled: ES Group Coastal/Estuaries
Inland hydrology controlled
Alluvium parent material
R220XY450AK – Estuarine Herbaceous Loamy Floodplain
R220XY450AK – Estuarine Herbaceous Loamy Floodplain
Marine and fluvial marine deposits
Silty and clayey marine deposits with flooding and potential ponding
R220XY329AK – Estuarine Herbaceous Tidal Marsh
R220XY329AK – Estuarine Herbaceous Tidal Marsh
Sandy deposits and eolian sands
Water table above 30 inches
R220XY424AK – Estuarine Herbaceous Sandy Beach Plain
R220XY424AK – Estuarine Herbaceous Sandy Beach Plain
no water table above 30 inches
R220XY422AK – Estuarine Herbaceous Dry Sand
R220XY422AK – Estuarine Herbaceous Dry Sand
Open, non-channel, hydrology
Riparian, or channel driven, hydrology: ES Group 1: Floodplains and drainageways
ES Group 2 - Open Wetlands
ES Group 3 - Wooded Wetlands
Depressions
Glacial valley floors
R220XY436AK – Maritime Graminoid Loamy Wet Plain
R220XY436AK – Maritime Graminoid Loamy Wet Plain
Thick organic horizons (Histosols), commonly associated with muskegs.
R220XY434AK – Maritime Scrubland Peat Plain Depression
R220XY434AK – Maritime Scrubland Peat Plain Depression
Comparatively thinner organic horizons (Inceptisols and Entisols).
R220XY461AK – Maritime Scrub Sandy Depressions
R220XY461AK – Maritime Scrub Sandy Depressions
nearly level to gentle slopes. Common on outwash delta, outwash plains, and till plains.
Steeper slopes then above. Footslopes and backslopes of hills and mountains.
F220XY447AK – Maritime Forest Loamy Organic Slopes
F220XY447AK – Maritime Forest Loamy Organic Slopes
Coarse-textured soils (sandy and sandy-skeletal particle size class)
F220XY455AK – Maritime Forest Sandy Coastal Plain
F220XY455AK – Maritime Forest Sandy Coastal Plain
Fine-textured soils (coarse-loamy, fine-loamy particle size class)
F220XY435AK – Maritime Forest Loamy Wet Plains
F220XY435AK – Maritime Forest Loamy Wet Plains
Active floodplains
Drainageways
Lower floodplain along channel, shrub dominated
R220XY426AK – Maritime Shrub Low Flood Plain
R220XY426AK – Maritime Shrub Low Flood Plain
Higher floodplain or floodplain step, above channel, forest dominated
F220XY427AK – Maritime Forest Gravelly High Floodplain
F220XY427AK – Maritime Forest Gravelly High Floodplain
Steeper sloping drainageways on mountain slopes and hills
R220XY444AK – Maritime Scrub Gravelly Steep Drainageways
R220XY444AK – Maritime Scrub Gravelly Steep Drainageways
Lower sloping drainageways along coastal plains and outwash
R220XY425AK – Maritime Shrub Drainageway
R220XY425AK – Maritime Shrub Drainageway
Shrub and scrub driven upland or neutral sites: ES Group 6 - Upland Scrub
Tree, or forested, driven sites
Steep active slopes (Avalanche driven communities)
R220XY443AK – Maritime Scrub Loamy Steep Slopes
R220XY443AK – Maritime Scrub Loamy Steep Slopes
Steep, stable or less active slopes, shallow soils
R220XY446AK – Maritime Scrub Loamy Escarpments
R220XY446AK – Maritime Scrub Loamy Escarpments
Higher Elevation and slope driven sites: ES Group 5 - Forested Slopes and Mountains
Lower elevation hills and flat sites: ES Group 4 - Forested flats and hills
Shallow organic soils
F220XY439AK – Maritime Stunted Woodland Shallow Organic Slopes
F220XY439AK – Maritime Stunted Woodland Shallow Organic Slopes
Non-organic soils
Coarser textured soils (sands and gravels)
Finer textured, loamy soils
Alluvial soils and alluvium driven sites
F220XY430AK – Maritime Forest Sandy Plain Alluvial Fan
F220XY430AK – Maritime Forest Sandy Plain Alluvial Fan
Gravelly slopes
F220XY441AK – Maritime Forest Gravelly Slopes
F220XY441AK – Maritime Forest Gravelly Slopes
Mid to low elevation slopes
High elevation slopes
F220XY433AK – Maritime Forest Loamy Slopes
F220XY433AK – Maritime Forest Loamy Slopes
Warmer, south aspect slopes
F220XY468AK – Maritime Forest Loamy Slopes Warm
F220XY468AK – Maritime Forest Loamy Slopes Warm
Steeper, non-aspect affected slopes
F220XY442AK – Maritime Forest Loamy Steep Slopes
F220XY442AK – Maritime Forest Loamy Steep Slopes
Shallow soils
F220XY440AK – Maritime Forest Loamy Plains
F220XY440AK – Maritime Forest Loamy Plains
Deep to very deep soils
Eolian or wind deposited materials
F220XY466AK – Maritime Forest Sandy Plains Eolian
F220XY466AK – Maritime Forest Sandy Plains Eolian
Alluvial or outwash materials
Alluvium on stream terraces
F220XY460AK – Maritime Forest Gravelly Alluvial Plains
F220XY460AK – Maritime Forest Gravelly Alluvial Plains
Glacial outwash and till deposits
F220XY432AK – Maritime Forest Gravelly Plain
F220XY432AK – Maritime Forest Gravelly Plain
Long term average mean annual precipitation
- No filter
- 140 – 500cm (55 – 197in)
—
cm
Long term average frost free days
- No filter
- 110 – 130days
—
days
- No filter
- 0 – 200m (0 – 700ft)
- 200 – 400m (700 – 1300ft)
- 400 – 600m (1300 – 2000ft)
- 600 – 800m (2000 – 2600ft)
- 800 – 1000m (2600 – 3300ft)
- 1000 – 1200m (3300 – 3900ft)
- 1200 – 1400m (3900 – 4600ft)
- 1400 – 1600m (4600 – 5200ft)
—
m
- No filter
- 0 – 3%
- 3 – 5%
- 5 – 10%
- 10 – 15%
- 15 – 20%
- 20 – 25%
- 25 – 30%
- 30 – 35%
- 35 – 40%
- 40 – 45%
- 45 – 50%
- 50 – 60%
- 60 – 70%
- 70 – 80%
- 80 – 90%
- 90 – 100%
—
%
- No filter
- Abandoned channel
- Alluvial fan
- Avalanche chute
- Beach plain
- Beach ridge
- Beach terrace
- Delta
- Depression
- Drainageway
- Dune
- Dune slack
- Escarpment
- Flood plain
- Fluviomarine bottom
- Fluviomarine terrace
- Glacial-valley floor
- Hill
- Hillslope
- Marine terrace
- Moraine
- Mountain
- Mountain slope
- Mountain valley
- Muskeg
- Outwash delta
- Outwash plain
- Stream terrace
- Terrace
- Tidal marsh
- Till plain
- No filter
- Graywacke
- Limestone, unspecified
- Metamorphic, unspecified
- Sedimentary, unspecified
- No filter
- Alluvium
- Beach sand
- Colluvium
- Eolian deposits
- Eolian sands
- Estuarine deposits
- Fluviomarine deposits
- Glaciofluvial deposits
- Lacustrine deposits
- Loess
- Marine deposits
- Organic, mossy material
- Organic, unspecified
- Outwash
- Residuum
- Till, ablation
- Till, unspecified
- Volcanic ash
Soil surface texture
- No filter
- Coarse sand
- Coarse sandy loam
- Fine sand
- Fine sandy loam
- Loam
- Loamy coarse sand
- Loamy fine sand
- Loamy sand
- Loamy very fine sand
- Sand
- Sandy clay
- Sandy clay loam
- Silt
- Silty clay loam
- Silt loam
- Sandy loam
- Very fine sand
- Very fine sandy loam
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Ecological site keys
MLRA 220 - Alexander Archipelago-Gulf of Alaska Coast - Master Key
I.
Elevation typically between 0 and 3000 feet and vegetation representative of the subalpine and maritime life zones. This vegetation represents the Alexander Archipelago-Gulf of Alaska Coast Area (MLRA 220).
A.
Elevation between 1500 and 3000 feet and vegetation representative of the subalpine life zone.
B.
Elevation typically between 0 and 1500 feet and vegetation representative of the maritime life zone.
II.
Elevation ≥ 3000 feet and vegetation representative of the alpine life zone. Alpine vegetation belongs to the Southern Alaska Coastal Mountains Area (MLRA 222).
Subalpine Ecological Sites Key
I.
Parent material is alluvium. Site associated with flood plains.
A.
persistent water table throughout the growing season.
... R220XY362AK – Subalpine Sedge Wet Flood Plain
II.
Parent material not alluvium and landform not associated with flood plain.
A.
Soils are primarily organic material over bedrock.
B.
Not as above. Parent material typically colluvium and/or residuum.
1
Soil parent material is calcareous.
... F220XY202AK – Subalpine Woodlands Gravelly Dry Slopes, Limestone
2
Soil parent material is not calcareous.
i.
Site associated with avalanche chutes or soil creep. Alder is typically common and dominant.
b.
Site associated with soil creep. Soils commonly have buried, mixed, and/or broken soil horizons. Soils with thick A-horizons are common.
... R220XY358AK – Subalpine Scrub Gravelly Dry Slopes
ii.
Not as above.
a.
Well- to moderately-well drained soils. Soils do not have a persistent water table at any depth during the growing season.
1)
Occurs at the lowest band of subalpine vegetation. Trees more productive compared to es 350. Krummholz and alpine species less common.
... F220XY200AK – Subalpine Forest Gravelly Dry Slopes
2)
Occurs at the highest band of subalpine vegetation. Trees less productive compared to es 200. Krummholz and alpine species more common.
... F220XY350AK – Subalpine Woodland Gravelly Dry Slopes
Lowland Maritime Ecological Site Key
I.
Hydrologic-driven (water influenced) communities
A.
Coastal hydrology controlled: ES Group Coastal/Estuaries
2
Marine and fluvial marine deposits
i.
Silty and clayey marine deposits with flooding and potential ponding
... R220XY329AK – Estuarine Herbaceous Tidal Marsh
ii.
Sandy deposits and eolian sands
B.
Inland hydrology controlled
1
Open, non-channel, hydrology
i.
ES Group 2 - Open Wetlands
a.
Depressions
1)
Thick organic horizons (Histosols), commonly associated with muskegs.
... R220XY434AK – Maritime Scrubland Peat Plain Depression
2)
Comparatively thinner organic horizons (Inceptisols and Entisols).
... R220XY461AK – Maritime Scrub Sandy Depressions
ii.
ES Group 3 - Wooded Wetlands
a.
nearly level to gentle slopes. Common on outwash delta, outwash plains, and till plains.
1)
Coarse-textured soils (sandy and sandy-skeletal particle size class)
... F220XY455AK – Maritime Forest Sandy Coastal Plain
2)
Fine-textured soils (coarse-loamy, fine-loamy particle size class)
... F220XY435AK – Maritime Forest Loamy Wet Plains
b.
Steeper slopes then above. Footslopes and backslopes of hills and mountains.
... F220XY447AK – Maritime Forest Loamy Organic Slopes
2
Riparian, or channel driven, hydrology: ES Group 1: Floodplains and drainageways
i.
Active floodplains
b.
Higher floodplain or floodplain step, above channel, forest dominated
... F220XY427AK – Maritime Forest Gravelly High Floodplain
ii.
Drainageways
a.
Steeper sloping drainageways on mountain slopes and hills
... R220XY444AK – Maritime Scrub Gravelly Steep Drainageways
b.
Lower sloping drainageways along coastal plains and outwash
... R220XY425AK – Maritime Shrub Drainageway
II.
Not hydrologically driven (nor water influenced) communities
A.
Shrub and scrub driven upland or neutral sites: ES Group 6 - Upland Scrub
1
Steep active slopes (Avalanche driven communities)
... R220XY443AK – Maritime Scrub Loamy Steep Slopes
2
Steep, stable or less active slopes, shallow soils
... R220XY446AK – Maritime Scrub Loamy Escarpments
B.
Tree, or forested, driven sites
1
Higher Elevation and slope driven sites: ES Group 5 - Forested Slopes and Mountains
ii.
Non-organic soils
a.
Coarser textured soils (sands and gravels)
1)
Alluvial soils and alluvium driven sites
... F220XY430AK – Maritime Forest Sandy Plain Alluvial Fan
b.
Finer textured, loamy soils
1)
Mid to low elevation slopes
2
Lower elevation hills and flat sites: ES Group 4 - Forested flats and hills
ii.
Deep to very deep soils
b.
Alluvial or outwash materials
The Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
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