Natural Resources
Conservation Service
Ecological site QX197X01X507
Dry Coastal Forest
Last updated: 8/22/2026
Accessed: 10/08/2026
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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): 197X–Volcanic Islands of American Samoa
This MLRA consists of the islands of Tutuila, Aunuu, Ofu, Olosega, and Tau. The islands have extremely steep, highly dissected mountains, small valleys, and a narrow coastal plain. More than half of the area has slopes of more than 70 percent. The highest elevations are 3,056 feet (930 meters) on Tau and 2,142 feet (650 meters) on Tutuila. The islands consist of Pleistocene-age, basic igneous rocks, mainly basalt with some andesite and trachyte (USDA-NRCS, 2006).
The climate is moist, warm, and humid. Average annual rainfall ranges from 125 inches (3,175 millimeters) to more than 250 inches (6,350 millimeters). Rainfall varies over short distances due to topography. The driest months are June through September; the wettest months are December through March. Average annual temperature is 81 degrees F (27 degrees C). Relative humidity is 73 to 90 percent throughout the year. Prevailing winds are easterly trade winds. Cyclones occasionally strike the area (USDA-NRCS, 2006).
Soils are Mollisols, Andisols, Entisols, Oxisols, and Histosols. Soil moisture regimes are udic or perudic; the soil temperature regime is isohyperthermic. Natural vegetation is mostly tropical hardwood forest (USDA-NRCS, 2006).Classification relationships
This ecological site occurs within Major Land Resource Area (MLRA) 197 – Volcanic Islands of American Samoa.
Ecological site concept
This ecological site occurs on the islands of Tutuila and Tau in American Samoa. It occurs on near level to steep (0 to 40 percent) uplands near the coast at elevations ranging from 0 to 390 feet (0 to 120 meters) elevation. Access is easy on the south side of Tutuila and restricted elsewhere (Green et al., 2015; USDA-SCS, 1984).
Soils are in the Andisols order. They formed in volcanic ash overlying tuff or lava. Soil temperature regimes are isohyperthermic; soil moisture regimes are udic. Average annual rainfall ranges from 128 to 133 inches (3,250 to 3,380 millimeters). Water runoff is slow to rapid. Soil temperatures are slightly warmer than those in most other areas of American Samoa. Effective rooting depths range from 8 to 28 inches (20 to 70 centimeters). Rock fragment content is absent except in the case of one soil. Salty sea winds commonly occur, and soils may sometimes become relatively dry (USDA-SCS, 1984).
This forest type has the highest tree density in American Samoa. The tree canopy grows up to 49 feet (15 meters) tall. Ground cover and epiphytes are sparse (USDA-SCS, 1984; Whistler, 2002).Associated sites
QX197X01X503 Lavaflow Forest
Lavaflow Forest Ecological Site adjoins Dry Coastal Forest Ecological Site where uplands and mountain slopes descend to young aa lava flows near the coast. Lavaflow Forest Ecological Site has organic soils that formed in the interstices between aa rocks. Dry Coastal Forest Ecological Site has mineral soils formed from volcanic ash deposited over hard tuff, or, in one case, in the interstices between aa rocks.
QX197X01X504 Alluvial Valley Forest
Alluvial Valley Forest Ecological Site adjoins Dry Coastal Forest Ecological Site where sloping uplands, side slopes, and mountain slopes descend to alluvium-filled valleys near the coast. Alluvial Valley Forest Ecological Site has somewhat poorly drained Cumulic Mollisols with very deep rooting depth that formed in alluvium. Dry Coastal Forest Ecological Site has well drained Andisols with limited rooting depth formed from volcanic ash deposited over hard tuff, or, in one case, in the interstices between aa rocks.
QX197X01X509 Very Steep Forest
Very Steep Forest Ecological Site adjoins Dry Coastal Forest Ecological Site where very steep mountain slopes descend to meet lower elevation, less steep slopes. Very Steep Forest Ecological Site consists of Andisols, Andic Mollisols, and Mollisols on slopes of 70 to 130 percent, at elevations of up to 2,100 feet, and having mean annual rainfall of 150 to 250 inches. Dry Coastal Forest Ecological Site consists of Andisols on slopes of 0 to 40 percent, at elevations up to 400 feet, and having mean annual rainfall of 120 to 160 inches.
Similar sites
QX197X01X502 Sandy Littoral Forest
Dry Coastal Forest Ecological Site is similar to Sandy Littoral Forest Ecological Site in that both ecological sites are exposed to more-or-less salt-laden winds near the coast. They differ in that Dry Coastal Forest Ecological Site occurs to elevations of 400 feet, has well drained soils, and does not undergo flooding, whereas Sandy Littoral Forest Ecological Site occurs to elevations of 15 feet, has somewhat excessively to excessively drained soils, and undergoes occasional, very brief to brief flooding by seawater.
Table 1. Dominant plant species
Tree (1) Diospyros
Shrub Not specified
Herbaceous (1) Asplenium nidus
Legacy ID
F197XY507AS
Physiographic features
This ecological site occurs on cinder cones and craters on mountain slopes or low elevation hillslopes.
Table 2. Representative physiographic features
Landforms (1) Island > Mountain slope
(2) Island > Cinder cone
(3) Island > Hillslope
Runoff class Low to high Flooding frequency None Ponding frequency None Elevation 0 – 390 ft Slope 0 – 40 % Water table depth 60 in Aspect Aspect is not a significant factor Climatic features
The area is characterized by abundant rain and warm, humid days and nights. Average annual precipitation in this ecological site ranges from 128 to 133 inches (3,250 to 3,380 millimeters). Mean annual air temperature is 80 degrees F (27 degrees C). The driest period is June through September (winter), and the wettest is December through March (summer), although heavy showers and long, rainy periods can occur in any month. June, July, and August are the coolest months, and January, February, and March are the warmest. Daytime temperatures typically reach the upper 80 degrees F in summer and the middle 80 degrees F in winter, while nighttime temperatures are in the middle 70 degrees F in summer and low 70 degrees F in winter.
The prevailing winds throughout the year are the easterly trade winds. They tend to be more directly from the east in December through March and mostly from the east-southeast and southeast during the rest of the year. The trade winds are less prevalent in summer than in winter. About 25 to 30 thunderstorms occur in an average year, mainly during the rainy season. The area lies across the path of tropical disturbances, including cyclones, that come usually from the north, but occasionally from east or west.Table 3 Representative climatic features
Frost-free period (characteristic range) 370 days Freeze-free period (characteristic range) 370 days Precipitation total (characteristic range) 130-130 in Frost-free period (actual range) 370 days Freeze-free period (actual range) 370 days Precipitation total (actual range) 120-160 in Frost-free period (average) 370 days Freeze-free period (average) 370 days Precipitation total (average) 130 in Characteristic rangeActual rangeBarLineFigure 1. Monthly precipitation range
Characteristic rangeActual rangeBarLineFigure 2. Monthly minimum temperature range
Characteristic rangeActual rangeBarLineFigure 3. Monthly maximum temperature range
BarLineFigure 4. Monthly average minimum and maximum temperature
Figure 5. Annual precipitation pattern
Figure 6 Annual average temperature pattern
Climate stations used
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(1) PAGO PAGO WSO AP [AQW00061705], AS
">Influencing water features
There are no water features in this site.
Soil features
Soils are in the Andisols order. They formed in volcanic ash overlying residuum weathered from tuff or basalt. Soil temperature regimes are isohyperthermic and soil moisture regimes are udic. Soil temperatures are slightly warmer than those in most other areas of American Samoa. Effective rooting depths range from 8 to 28 inches (20 to 70 centimeters). Rock fragment content is absent except in the case of Iliili. Soil components correlated to this ecological site are Iliili (5, 32), Puapua (26, 28, 29, 30), and Sogi (28, 29, 30).
Table 4. Representative soil features
Parent material (1) Volcanic ash – basalt
(2) Volcanic ash – tuff
(3) Residuum
Surface texture (1) Clay loam
(2) Highly organic, extremely stony clay loam
Family particle size (1) Medial
(2) Medial-skeletal
(3) Medial over ashy
Drainage class Well drained Permeability class Moderately rapid to rapid Depth to restrictive layer 8 – 28 in Soil depth 8 – 28 in Surface fragment cover <=3" 5 – 9 % Surface fragment cover >3" Not specified Available water capacity
(0-40in)3 – 5.5 in Calcium carbonate equivalent
(0-40in)Not specified Electrical conductivity
(0-40in)Not specified Sodium adsorption ratio
(0-40in)0 – 1 Soil reaction (1:1 water)
(0-40in)6.1 – 7.3 Subsurface fragment volume <=3"
(0-40in)5 – 9 % Subsurface fragment volume >3"
(0-40in)Not specified Table 5. Representative soil features (actual values)
Drainage class Not specified Permeability class Not specified Depth to restrictive layer 0 in Soil depth 0 in Surface fragment cover <=3" 0 % Surface fragment cover >3" 0 – 55 % Available water capacity
(0-40in)1 – 5.6 in Calcium carbonate equivalent
(0-40in)0 % Electrical conductivity
(0-40in)0 mmhos/cm Sodium adsorption ratio
(0-40in)0 Soil reaction (1:1 water)
(0-40in)0 Subsurface fragment volume <=3"
(0-40in)0 % Subsurface fragment volume >3"
(0-40in)0 – 55 % Ecological dynamics
The main natural disturbance is strong storms that can damage or kill vegetation by high wind speeds. The main human disturbance is clearing of native vegetation to create grassland and abandonment of grassland that may result in at least temporary dominance of introduced weedy plants (Forestry Program, Division of Community and Natural Resources, 2010; Sene, 2020; Space and Flynn, 2000; Webb and Fa`aumu, 1999; Whistler, 2002).
Many species specific names are not in USDA Plants Database, but can be found in the listed references or in other sources online, like Plants of the World Online from the Kew Royal Botanic Gardens or iNaturalist. Many common names in the State and Transition model are locally known names.State and transition model
Custom diagramStandard diagram
More interactive model formats are also available. View Interactive Models
More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective textEcosystem states
T1A - Removal of native vegetation and planting, or allowing colonization by, introduced grass species. T1B - Previously cleared of forest and then abandoned. T1C - Wind damage or ungulate grazing to the forest when there is a nearby source of seeds of invasive species. R2A - Suppression of grassland vegetation and replanting with native species. T2B - Abandonment of grasslands. R3B - Active restoration measures. R3A - Land clearing, weed control, and replanting grasses. T3A - Growth of an overstory of trees with an understory of shade-tolerant shrubs, vines, ferns, forbs, and grasses. R4A - Active restoration measures. R4B - Presence of an abundant tree seed bank in the soil. State 1 submodel, plant communities
1.1A - Storms or fires that damage or kill trees causes a canopy opening. 1.2A - Adequate time to recover after disturbance. State 2 submodel, plant communities
2.1A - Invasion of the site by shrubs and forbs. 2.2A - Reducing grazing and browsing pressure and weed control. State 3 submodel, plant communities
State 4 submodel, plant communities
State 1
Reference StateThis ecological site is a forest with a medium tall (50 feet or 15 meters) tree canopy and high tree density. Ground cover is sparse, and epiphytes are few. Soils can sometimes become dry. This site is exposed to salty sea winds (Forestry Program, Division of Community and Natural Resources, 2010; Sene, 2020; Space and Flynn, 2000; Webb and Fa`aumu, 1999; Whistler, 2002).
Dominant plant species
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diospyros (Diospyros), tree
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sea hibiscus (Hibiscus tiliaceus), tree
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Hawai'I birdnest fern (Asplenium nidus), other herbaceous
Community 1.1
Au Auli – Anume/Hawai'i Birdnest FernDominant tree species are auauli (Diospyros samoensis), anume (Diospyros foliosa), alaa (Planchonella garberi), tiger's claw (Erythrina variegata), asi vao (Syzygium clusiifolium), mana ui (Garuga floribunda), sea putat (Barringtonia asiatica), tropical almond (Terminalia catappa), and asi vai (Syzygium dealatum). Sea or beach hibiscus (Hibiscus tiliaceus) also may occur (Forestry Program, Division of Community and Natural Resources, 2010; Green et al., 2015; Sene, 2020; Webb and Fa`aumu, 1999; Whistler, 2002; Whistler, 1994; Whistler, 1992).
Ferns include Hawai'i birdnest fern (Asplenium nidus), haresfoot ferns (Davallia spp.), and musk fern (Phymatosorus grossum). Batflower or Polynesian arrowroot (Tacca leontopetaloides), an ancient introduction, occurs in places. The epiphytic orchids Dendrobium dactylodes and Dendrobium cunninghamii (biflorum) are common. Climbing vines include fue selela (Hoya australis), maunaloa (Canavalia cathartica), rosarypea or matamoso (Abrus precatorius), seabean (Mucuna gigantea), threeleaf derris or fue oona (Derris trifoliata), fue manogi (Piper macropiper var. macropiper), centipede tongavine or fue laufao (Epipremnum pinnatum), Jasminum didymum, and ieie (Freycinetia spp.) (Forestry Program, Division of Community and Natural Resources, 2010; Green et al., 2015; Sene, 2020; Webb and Fa`aumu, 1999; Whistler, 2002; Whistler, 1994; Whistler, 1992).Dominant plant species
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diospyros (Diospyros), tree
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Hawai'I birdnest fern (Asplenium nidus), other herbaceous
Community 1.2
Diospyros spp. – Beach HibiscusThe same tree species as in Community Phase 1.1 remain in this phase, but other tree species, commonly sea or beach hibiscus (Hibiscus tiliaceus) can join the canopy as the forest regrows. Ground vegetation becomes temporarily more abundant. Epiphytes are less common than in 1.1 (Forestry Program, Division of Community and Natural Resources, 2010; Green et al., 2015; Sene, 2020; Webb and Fa`aumu, 1999; Whistler, 2002; Whistler, 1994; Whistler, 1992).
Dominant plant species
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diospyros (Diospyros), tree
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sea hibiscus (Hibiscus tiliaceus), tree
Pathway 1.1A
Community 1.1 to 1.2Storms or fires that damage or kill trees causes a phase change from 1.1 to 1.2 typified by a partial, temporary change in dominant tree species and a temporary increase in ground level vegetation.
Pathway 1.2A
Community 1.2 to 1.1This community phase will revert to phase 1.1 with gradual regrowth of native species when given adequate time to recover after disturbance.
State 2
Naturalized Grassland StateThis community phase is dominated by hilograss (Paspalum conjugatum). When not excessively grazed, it includes the legume Spanish clover (also called zarzbacoa comun) (Desmodium incanum). White leadtree (Leucaena leucocephala) may be present. This small, leguminous tree is browsed by cattle (Forestry Program, Division of Community and Natural Resources, 2010; Green et al., 2015; Sene, 2020; Space and Flynn, 2000; USDA-SCS, 1984; Webb and Fa`aumu, 1999; Whistler, 2002; Whistler, 1994; Whistler, 1992).
Dominant plant species
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white leadtree (Leucaena leucocephala), tree
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hilograss (Paspalum conjugatum), grass
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zarzabacoa comun (Desmodium incanum), other herbaceous
Community 2.1
White Leadtree/Hilograss/Spanish CloverThis community phase is dominated by hilograss (Paspalum conjugatum). When not excessively grazed, it includes the legume Spanish clover (Desmodium incanum). White leadtree (Leucaena leucocephala) may be present. This small, leguminous tree is browsed by cattle (Forestry Program, Division of Community and Natural Resources, 2010; Green et al., 2015; Sene, 2020; USDA-SCS, 1984; Space and Flynn, 2000; Webb and Fa`aumu, 1999; Whistler, 2002; Whistler, 1994; Whistler, 1992).
Dominant plant species
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white leadtree (Leucaena leucocephala), tree
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hilograss (Paspalum conjugatum), grass
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zarzabacoa comun (Desmodium incanum), other herbaceous
Community 2.2
Comb Bushmint – Nettleleaf Velvetberry/Bermudagrass – HilograssThis community phase consists largely of Bermudagrass (Cynodon dactylon) and hilograss. Shrubs, vines, and forbs occupy some of the site due to reduction of grass competitiveness by excessive grazing. Some common species include: redflower ragleaf or fua lele (Crassocephalum crepidioides) a large, invasive forb; comb bushmint (Hyptis pectinata), a shrub; diamond burbank or mautofu (Triumfetta rhomboidea), a tall shrub; and nettleleaf velvetberry (Stachytarpheta urticifolia), a low shrub. Remnant white leadtree (Leucaena leucocephala) are probably present.
Dominant plant species
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comb bushmint (Hyptis pectinata), shrub
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nettleleaf velvetberry (Stachytarpheta urticifolia), shrub
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Bermudagrass (Cynodon dactylon), grass
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hilograss (Paspalum conjugatum), grass
Pathway 2.1A
Community 2.1 to 2.2Community phase 2.1 will change to 2.2 by invasion of the site by shrubs and forbs. This process is facilitated by excessive grazing and browsing, which reduces the competitive advantage of hilograss and white leadtree.
Pathway 2.2A
Community 2.2 to 2.1Community phase 2.2 can shift back to phase 2.1 by reducing grazing and browsing pressure on remnant hilograss and white leadtree and, when necessary, performing spot weed control on shrubs and vines.
State 3
Cleared and Abandoned StateThis state consists of one community phase dominated by a variable mixture of small trees, shrubs, vines, forbs, and grasses that thrive in sunny environments. Remnant hilograss is present.
Dominant plant species
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sensitive plant (Mimosa), shrub
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Bermudagrass (Cynodon dactylon), grass
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hilograss (Paspalum conjugatum), grass
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romerillo (Bidens alba), other herbaceous
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mile-a-minute (Mikania micrantha), other herbaceous
Community 3.1
Giant Sensitive Plant/Beggar’s Tick/Mile-A-Minute Vine/Bermudagrass – HilograssThis community phase consists of Bermudagrass and hilograss with a variable array of shrubs, forbs, vines, and young trees that thrive in sunny environments. Giant sensitive plant (Mimosa diplotricha), comb bushmint (Hyptis pectinata), mautofu (Triumfetta rhomboidea), and nettleleaf velvetberry (Stachytarpheta urticifolia) are dominant. The shrub layer may also include seedlings and saplings of any native trees that may have persisted on or near the site or invasive, introduced tree species such as African tuliptree (Spathodea campanulata), red beadtree (Adenanthera pavonina), and tamaligi or peacocksplume (Falcataria moluccana). Romerillo (Bidens alba), mile-a-minute vine (Mikania micrantha) and the large, introduced forb fua lele (Crassocephalum crepidioides) may be present.
Dominant plant species
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sensitive plant (Mimosa), shrub
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Bermudagrass (Cynodon dactylon), grass
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hilograss (Paspalum conjugatum), grass
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romerillo (Bidens alba), other herbaceous
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mile-a-minute (Mikania micrantha), other herbaceous
State 4
Invaded Forest StateThis state consists of one community phase. It is forested with both overstory and understory composed of a variable mix of native and introduced species. The actual species composition on a given site depends on the original native species composition, the disturbance history, and the species composition existing near the site before, during, and after disturbances (Forestry Program, Division of Community and Natural Resources, 2010; Green et al., 2015; Sene, 2020; Space and Flynn, 2000; USDA-SCS, 1984; Webb and Fa`aumu, 1999; Whistler, 2002; Whistler, 1994; Whistler, 1992).
Dominant plant species
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diospyros (Diospyros), tree
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African tuliptree (Spathodea campanulata), tree
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derris (Derris), shrub
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running mountaingrass (Oplismenus compositus), grass
Community 4.1
Diospyros Spp. – African Tuliptree/New Guinea Creeper/Running MountaingrassThe overstory consists of large trees. Any of the native species listed for State 1 Reference may be present. Introduced tree species are likely to be present; common examples of these are African tuliptree (Spathodea campanulata), tamaligi or peacocksplume (Falcataria moluccana), and red beadtree (Adenanthera pavonina) (Forestry Program, Division of Community and Natural Resources, 2010; Green et al., 2015; Sene, 2020; Space and Flynn, 2000; USDA-SCS, 1984; Webb and Fa`aumu, 1999; Whistler, 2002; Whistler, 1994; Whistler, 1992).
The understory consists of an unpredictable mixture of native and introduced shrubs, ferns, vines, forbs, and grasses that have some shade tolerance. See State 1 Reference for examples of native species. Common examples of introduced understory species are New Guinea creeper (Derris malaccensis) and running mountaingrass (Oplismenus compositus) (Forestry Program, Division of Community and Natural Resources, 2010; Green et al., 2015; Sene, 2020; Space and Flynn, 2000; USDA-SCS, 1984; Webb and Fa`aumu, 1999; Whistler, 2002; Whistler, 1994; Whistler, 1992).Dominant plant species
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diospyros (Diospyros), tree
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African tuliptree (Spathodea campanulata), tree
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derris (Derris), shrub
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running mountaingrass (Oplismenus compositus), grass
Transition T1A
State 1 to 2The Reference State (1) transitions to the Naturalized Grassland State (2) by removal of native vegetation and planting, or allowing colonization by, introduced grass species.
Transition T1B
State 1 to 3The Reference State (1) transitions to the Cleared and Abandoned State (3) if previously cleared of forest and then abandoned. This allows heliophytes, both native and introduced, to temporarily cover the ground.
Transition T1C
State 1 to 4The Reference State (1) transitions to the Invaded Forest State (4) by wind damage to the forest when there is a nearby source of seeds of invasive species or, more gradually, by damage to the forest understory by ungulates, especially feral pigs, when there is a source of seeds of invasive species.
Restoration pathway R2A
State 2 to 1The Naturalized Grassland State (2) can be restored to the Reference State (1) by suppression of grassland vegetation and replanting with native species. Natural reseeding by native forest species can be expected if there is a nearby stand of suitable species.
Transition T2B
State 2 to 3The Naturalized Grassland State (2) transitions to the Cleared and Abandoned State (3) upon abandonment of grasslands, which are invaded by low-statured, native or introduced heliophytes.
Restoration pathway R3B
State 3 to 1The Cleared and Abandoned State (3) may be restored to the Reference State (1). The intensity of active restoration measures will be determined by the presence or lack of nearby native forest or, at least, some native trees as well as the density and species mix of grasses, vines, shrubs, and invasive trees present on the site, especially if many competitive introduced species are present.
Restoration pathway R3A
State 3 to 2The Cleared and Abandoned State (3) may be restored to the Naturalized Grassland State (2) by land clearing, weed control, and replanting grasses.
Transition T3A
State 3 to 4The Cleared and Abandoned State (3) transitions to the Invaded Forest State (4) by growth of an overstory of trees with an understory of shade-tolerant shrubs, vines, ferns, forbs, and grasses. The species mix is variable but may be mostly introduced species or a combination of native and introduced species.
Restoration pathway R4A
State 4 to 1The Invaded Forest State (4) can be restored to the Reference State (1). The difficulty, cost, and likelihood of success will depend on the species composition and amount and competitiveness of introduced species present on a given site.
Restoration pathway R4B
State 4 to 3The Invaded Forest State (4) Invaded Forest can be restored to the Cleared and Abandoned State (3). After this “restoration,” the Cleared and Abandoned State (3) is likely to rapidly transition back to the Invaded Forest State (4) due to presence of an abundant tree seed bank in the soil.
Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 7. Community 1.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 8. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 9. Community 2.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 10. Community 3.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 11. Community 4.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Supporting information
Inventory data references
NASIS soil component data.
Other references
Forestry Program, Division of Community and Natural Resources. (2010). American Samoa Forest Assessment and Resource Strategy. American Samoa Community College, Pago Pago, American Samoa.
Green, K, Kittel, G., Lopez, C., Ainsworth, A., Selvig, M., Vaivai, V., Akamine, K., Tukman, M., and Kudray, G. (2015). Vegetation Mapping Inventory Project, National Park of American Samoa. USDI-NPS Natural Resource Stewardship and Science. Fort Collins, Colorado.
Sene, D. M. (2020). Forest Action Plan. Forestry Program, American Samoa Community College, Pago Pago, American Samoa.
Space, J. C. and Flynn, T. (2000). Observations on invasive plant species in American Samoa. USDA Forest Service, Pacific Southwest Research Station, Honolulu. http://www.hear.org/pier/references/pierref000021.htm
USDA-NRCS. (2006). Major Land Resource Regions. USDA Agriculture Handbook 296. http://soils.usda.gov/MLRAExplorer
USDA-SCS. (1984). Soil Survey of Islands of American Samoa. Nakamura, S., Chavez, C. L. and Roybal, M. W. in cooperation with the Government of American Samoa.
USDI-FWS. (1982). Wildlife and Wildlife Habitat of American Samoa. II. Accounts of Flora and Fauna. R Banks, editor. Washington DC.
Webb, E. L. and Fa`aumu, S. (1999). Diversity and structure of tropical rain forest of Tutuila, American Samoa: effects of site age and substrate. Plant Ecology 44: 257-274.
Whistler, W. A. (2002). The Samoan Rainforest. Isle Botanica, Honolulu.
Whistler, W. A. (1994). Botanical Inventory of the Proposed Tutuila and Ofu Units of the National Park of American Samoa. Technical Report 87. National Park Service. Honolulu.
Whistler, W. A. (1992). Botanical Inventory of the Proposed Ta`u Unit of the National Park of American Samoa. Technical Report 83. National Park Service. Honolulu.Contributors
David Clausnitzer PhD
John Proctor
Ann Tan
Carolyn Auweloa
Daniel Bowman
Jennifer Fedenko
Amy Koch
Kendra Moseley
Sarah Quistberg
Jill Ficke-Beaton
Daniel Block
Brendan Brazee
Curtis TalbotApproval
Jamin Johanson, 8/22/2026
Acknowledgments
Assistance, advice, review, and/or insights: Michael Constantinides, NRCS-PIA Jennifer Higashino, USFWS and NRCS Mike Kolman, NRCS
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 06/16/2026 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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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:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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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:
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Perennial plant reproductive capability:
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PrintThe 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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