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Ecological site QX197X01X507

Dry Coastal Forest

Last updated: 6/12/2025
Accessed: 12/05/2025

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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): 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 (931 meters) on Tau and 2,142 feet (653 meters) on Tutuila. The islands consist of Pleistocene-age, basic igneous rocks, mainly basalt with some andesite and trachyte.

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.

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.

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 400 feet (0 to 123 meters) elevation. Access is easy on the south side of Tutuila and restricted elsewhere.

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 120 to 160 inches (300 to 400 centimeters). 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 40 inches (20 to 100 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.

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.

Associated sites

QX197X01X503	Lavaflow Forest Lavaflow Forest adjoins Dry Coastal Forest where uplands and mountain slopes descend to young aa lava flows near the coast. Lavaflow Forest has organic soils that formed in the interstices between aa rocks; Dry Coastal Forest 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 adjoins Dry Coastal Forest where sloping uplands, side slopes, and mountain slopes descend to alluvium-filled valleys near the coast. Alluvial Valley Forest has somewhat poorly drained Cumulic Mollisols with very deep rooting depth that formed in alluvium; Dry Coastal Forest 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 adjoins Dry Coastal Forest where very steep mountain slopes descend to meet lower elevation, less steep slopes. Very Steep Forest consists of Andisols, Andic Mollisols, and Mollisols on slopes of 70 to 130 percent, at elevations of 0 to 2100 feet, and having mean annual rainfall of 150 to 250 inches. Dry Coastal Forest consists of Andisols on slopes of 0 to 40 percent, at elevations of 0 to 400 feet, and having mean annual rainfall of 120 to 160 inches.

QX197X01X503

Lavaflow Forest

Lavaflow Forest adjoins Dry Coastal Forest where uplands and mountain slopes descend to young aa lava flows near the coast. Lavaflow Forest has organic soils that formed in the interstices between aa rocks; Dry Coastal Forest 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 adjoins Dry Coastal Forest where sloping uplands, side slopes, and mountain slopes descend to alluvium-filled valleys near the coast. Alluvial Valley Forest has somewhat poorly drained Cumulic Mollisols with very deep rooting depth that formed in alluvium; Dry Coastal Forest 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 adjoins Dry Coastal Forest where very steep mountain slopes descend to meet lower elevation, less steep slopes. Very Steep Forest consists of Andisols, Andic Mollisols, and Mollisols on slopes of 70 to 130 percent, at elevations of 0 to 2100 feet, and having mean annual rainfall of 150 to 250 inches. Dry Coastal Forest consists of Andisols on slopes of 0 to 40 percent, at elevations of 0 to 400 feet, and having mean annual rainfall of 120 to 160 inches.

Similar sites

QX197X01X502	Sandy Littoral Forest Dry Coastal Forest is similar to Sandy Littoral Forest in that both ecological sites are exposed to more-or-less salt-laden winds near the coast. They differ in that Dry Coastal Forest occurs to elevations of 400 feet, has well drained soils, and does not undergo flooding, whereas Sandy Littoral Forest occurs to elevations of 15 feet, has somewhat excessively to excessively drained soils, and undergoes occasional, very brief to brief flooding by seawater.

QX197X01X502

Sandy Littoral Forest

Dry Coastal Forest is similar to Sandy Littoral Forest in that both ecological sites are exposed to more-or-less salt-laden winds near the coast. They differ in that Dry Coastal Forest occurs to elevations of 400 feet, has well drained soils, and does not undergo flooding, whereas Sandy Littoral Forest 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

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Physiographic features

This ecological site occurs on mountain slopes.

Table 2. Representative physiographic features

Landforms	(1) Island > Mountain slope
Runoff class	Low to high
Flooding frequency	None
Ponding frequency	None
Elevation	600 ft
Slope	45%
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 (3250 to 3380 millimeters). Mean annual air temperature is 80F (27C). 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 80s in summer and the middle 80s F in winter, while nighttime temperatures are in the middle 70s in summer and low 70s 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)	365 days
Freeze-free period (characteristic range)	365 days
Precipitation total (characteristic range)	128-133 in
Frost-free period (actual range)	365 days
Freeze-free period (actual range)	365 days
Precipitation total (actual range)	120-163 in
Frost-free period (average)	365 days
Freeze-free period (average)	365 days
Precipitation total (average)	130 in

Characteristic range

Actual range

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Figure 1. Monthly precipitation range

Characteristic range

Actual range

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Figure 2. Monthly minimum temperature range

Characteristic range

Actual range

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Figure 3. Monthly maximum temperature range

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Figure 4. Monthly average minimum and maximum temperature

Figure 5. Annual precipitation pattern

Figure 6. Annual average temperature pattern

Climate stations used

(1) PAGO PAGO WSO AP [AQW00061705], AS

Soil features

ILIILI, PUAPUA, SOGI

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. Soil temperatures are slightly warmer than those in most other areas of American Samoa. Effective rooting depths range from 9 to 26 inches (23 to 66 centimeters). Rock fragment content is absent except in the case of Iliili.

Table 4. Representative soil features

Parent material	(1) Volcanic ash
Surface texture	(1) Clay loam (2) Mucky, extremely stony clay
Family particle size	(1) Medial (2) Medial-skeletal
Drainage class	Well drained
Permeability class	Very slow
Depth to restrictive layer	9 – 26 in
Soil depth	9 – 26 in
Surface fragment cover <=3"	Not specified
Surface fragment cover >3"	9%
Available water capacity (0-40in)	4 – 5 in
Calcium carbonate equivalent (0-40in)	Not specified
Electrical conductivity (0-40in)	Not specified
Sodium adsorption ratio (0-40in)	1
Soil reaction (1:1 water) (0-40in)	6.1 – 7.3
Subsurface fragment volume <=3" (0-40in)	9%
Subsurface fragment volume >3" (0-40in)	28%

Table 5. Representative soil features (actual values)

Drainage class	Not specified
Permeability class	Not specified
Depth to restrictive layer	Not specified
Soil depth	Not specified
Surface fragment cover <=3"	Not specified
Surface fragment cover >3"	Not specified
Available water capacity (0-40in)	1 – 5 in
Calcium carbonate equivalent (0-40in)	Not specified
Electrical conductivity (0-40in)	Not specified
Sodium adsorption ratio (0-40in)	Not specified
Soil reaction (1:1 water) (0-40in)	5.6 – 7.3
Subsurface fragment volume <=3" (0-40in)	Not specified
Subsurface fragment volume >3" (0-40in)	Not specified

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.

State and transition model

Custom diagram

Standard diagram

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Click on state and transition labels to scroll to the respective text

Ecosystem states

1. Reference State

2. Naturalized Grassland State

3. Cleared and Abandoned State

4. Invaded Forest State

T1A	-	State 1 Refence transitions to State 2 Naturalized Grassland by removal of native vegetation and planting, or allowing colonization by, introduced grass species.
T1B	-	State 1 Refence transitions to State 3 Cleared and Abandoned if previously cleared of forest and then abandoned. This allows heliophytes, both native and introduced, to temporarily cover the ground.
T1C	-	State 1 Reference transitions to State 4 Invaded Forest 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.
R2A	-	State 2 Naturalized Grassland can be restored to State 1 Reference 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.
T2B	-	State 2 Naturalized Grassland transitions to State 3 Cleared and Abandoned upon abandonment of grasslands, which are invaded by low-statured, native and/or introduced heliophytes.
R3B	-	State 3 Cleared and Abandoned may be restored to State 1 Reference. 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.
R3A	-	State 3 Cleared and Abandoned may be restored to State 2 Naturalized Grassland by land clearing, weed control, and replanting grasses.
T3A	-	State 3 Cleared and Abandoned transitions to State 4 Invaded Forest 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.
R4A	-	State 4 Invaded Forest can be restored to the Reference State. 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.
R4B	-	State 4 Invaded Forest can be restored to State 3 Cleared and Abandoned. After this “restoration,” State 3 is likely to rapidly transition back to State 4 due to presence of an abundant tree seed bank in the soil.

State 1 submodel, plant communities

1.1. Au auli – anume/bird’s nest fern

1.2. Diospyros spp. – beach hibiscus

P1.1A	-	Storms 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.
P1.2A	-	This community phase will revert to phase 1.1 with gradual regrowth of native species when given adequate time to recover after disturbance.

State 2 submodel, plant communities

2.1. White leadtree/Hilograss/Spanish clover

2.2. Comb bushmint – nettleleaf velvetberry/Bermudagrass – hilograss

P2.1A	-	Community 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.
P2.2A	-	Community 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 submodel, plant communities

3.1. Giant sensitive plant/beggar’s tick/mile-a-minute vine/Bermudagrass – hilograss

State 4 submodel, plant communities

4.1. Diospyros spp. – African tulip tree/New Guinea creeper/running mountaingrass

State 1
Reference State

This ecological site is 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.

Community 1.1
Au auli – anume/bird’s nest fern

Dominant tree species are auauli (Diospyros samoensis), anume (Diospyros elliptica, alaa (Planchonella garberi), Erythrina variegata, asi vao (Syzygium clusiifolium), mana ui (Garuga floribunda), Barringtonia asiatica, tropical almond (Terminalia catappa), and asi vai (Syzygium dealatum). Beach hibiscus (Hibiscus tiliaceus) also may occur. Ferns include bird’s nest fern (Asplenium nidus), haresfoot ferns (Davallia spp.), and musk fern (Microsorum grossum). Polynesian arrowroot (Tacca leontopetaloides), an ancient introduction, occurs in places. The epiphytic orchids Dendrobium dactylodes and Dendrobium biflorum are common. Climbing vines include fue selela (Hoya australis), mauna loa (Canavalia cathartica), matamoso (Abrus precatorius), sea bean (Mucuna gigantea), fue oona (Derris trifoliata), fue manogi (Piper graeffei), fue laufao (Epipremnum pinnatum), Jasminum didymum, and ieie (Freycinetia spp.).

Dominant plant species

diospyros (Diospyros), tree
Hawai'I birdnest fern (Asplenium nidus), other herbaceous

Community 1.2
Diospyros spp. – beach hibiscus

The same tree species as in Community Phase 1.1 remain in this phase, but other tree species, commonly 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.

Dominant plant species

diospyros (Diospyros), tree
sea hibiscus (Hibiscus tiliaceus), tree

Pathway P1.1A
Community 1.1 to 1.2

Storms 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 P1.2A
Community 1.2 to 1.1

This 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 State

This 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.

Community 2.1
White leadtree/Hilograss/Spanish clover

This 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.

Dominant plant species

white leadtree (Leucaena leucocephala), tree
hilograss (Paspalum conjugatum), grass
zarzabacoa comun (Desmodium incanum), other herbaceous

Community 2.2
Comb bushmint – nettleleaf velvetberry/Bermudagrass – hilograss

This community phase consists largely of Bermudagrass and hilograss. Shrubs, vines, and forbs occupy some of the site due to reduction of grass competitiveness by excessive grazing. Some common species include: fua lele (Crassocephalum crepidioides) a large, invasive forb; comb bushmint (Hyptis pectinata), a shrub; 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

comb bushmint (Hyptis pectinata), shrub
nettleleaf velvetberry (Stachytarpheta urticifolia), shrub
Bermudagrass (Cynodon dactylon), grass
hilograss (Paspalum conjugatum), grass

Pathway P2.1A
Community 2.1 to 2.2

Community 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 P2.2A
Community 2.2 to 2.1

Community 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 State

This 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.

Community 3.1
Giant sensitive plant/beggar’s tick/mile-a-minute vine/Bermudagrass – hilograss

This 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 tulip tree (Spathodea campanulata), red beadtree (Adenanthera pavonina), and tamaligi or peacocks plume (Falcataria moluccana). Mile-a-minute vine (Mikania micrantha) and the large, introduced forb fua lele (Crassocephalum crepidioides) may be present.

Dominant plant species

sensitive plant (Mimosa), shrub
Bermudagrass (Cynodon dactylon), grass
hilograss (Paspalum conjugatum), grass
romerillo (Bidens alba), other herbaceous
mile-a-minute (Mikania micrantha), other herbaceous

State 4
Invaded Forest State

This state consists of one community phase. It is forest 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.

Community 4.1
Diospyros spp. – African tulip tree/New Guinea creeper/running mountaingrass

The 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 tulip tree (Spathodea campanulata), tamaligi or peacocks plume (Falcataria moluccana), and red beantree (Adenanthera pavonina). 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).

Dominant plant species

diospyros (Diospyros), tree
African tuliptree (Spathodea campanulata), tree
derris (Derris), shrub
running mountaingrass (Oplismenus compositus), grass

Transition T1A
State 1 to 2

The 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 3

The 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 4

The 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 1

The 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 3

The Naturalized Grassland State (2) transitions to the Cleared and Abandoned State (3) upon abandonment of grasslands, which are invaded by low-statured, native and/or introduced heliophytes.

Restoration pathway R3B
State 3 to 1

The 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 2

The 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 4

The 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 1

The 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 3

The 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

Supporting information

Other references

Annotated References for F197XY507AS Dry Coastal Forest

Dixon JB and Schulze DG, eds. 2002. Soil Mineralogy with Environmental Applications. Volume 7. Soil Science Society of America. Available online at: https://acsess.onlinelibrary.wiley.com/doi/book/10.2136/sssabookser7 Exhaustive treatment of basics of soil mineralogy and implications for environmental management.

Forestry Program, Division of Community and Natural Resources. 2010. American Samoa Forest Assessment and Resource Strategy. American Samoa Community College, Pago Pago, American Samoa. Some discussion of disturbances, threats, and invasive species.

Green K, G Kittel, C Lopez, A Ainsworth, M Selvig, V Vaivai, K Akamine, M Tukman, and G Kudray. Vegetation Mapping Inventory Project, National Park of American Samoa. USDI-NPS Natural Resource Stewardship and Science. Fort Collins, Colorado. Discussion and maps of fine-scale vegetation associations, including Appendix with data including elevation ranges, litter, bare, and surface rockiness.

Kirch PV. 2000. On the Road of the Winds: An Archaeological History of the Pacific Islands Before European Contact. Berkeley: University of California Press. General discussion of effects of prehistoric Polynesians on native vegetation.

Mueller-Dombois D and FR Fosberg. 1998. Vegetation of the Tropical Pacific Islands. Springer-Verlag, New York. General account of tropical Pacific Island vegetation, with section on Hawaii. Discussion of likely effect of stoniness on soil moistue storage in dry habitats.

Sene DM. 2020. Forest Action Plan. Forestry Program, American Samoa Community College, Pago Pago, American Samoa. Discussions of forest types, disturbances, and succession.

Soil Survey Staff. 2014. Soil Taxonomy, Twelfth Edition. USDA – NRCS. Standard book of soil taxonomy; useful for terminology and interpretation of soils.

Space JC and T Flynn. 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 Recent, detailed report on invasive and potentially-invasive plants in American Samoa.

USDA-NRCS. 2011. Soil Survey Laboratory Information Manual. Soil Survey Investigations Report No. 45, Version 2.0. National Soil Survey Center, Lincoln, Nebraska. Provides additional insight for interpretation of soils information.

USDA-NRCS. 2006. Major Land Resource Regions. USDA Agriculture Handbook 296. http://soils.usda.gov/MLRAExplorer Description of MLRAs of Hawaii.

USDA-SCS. 1984. Soil Survey of Islands of American Samoa. Nakamura S, Chavez CL and MW Roybal, in cooperation with the Government of American Samoa. The latest NRCS soil survey for these islands. Some of the taxonomic names are outdated.

USDI-FWS. 1982. Woldlife and Wildlife Habitat of American Samoa. II. Accounts of Flora and Fauna. R Banks, editor. Washington DC. Discussion of vegetation as habitat types for local fauna. Good climate discussion.

USDI-NPS. 2009. Natural History Guide to American Samoa, 3rd Edition. P. Craig, editor. National Park of Samoa, Department of Marine and Wildlife Resources-American Samoa, American Samoa Community College-Community and Natural Resources Division. General reference for terrestrial and marine resources of American Samoa, with color photographs.

Webb EL. 2009. A Guide to the Native Ornamental Trees of American Samoa. Department of Marine and Wildlife Resources, Government of American Samoa. Guide to the more common and/or useful native trees recommended for planting in American Samoa, with color photographs and individual descriptions.

Webb EL and S Fa`aumu. 1999. Diversity and structure of tropical rain forest of Tutuila, American Samoa: effects of site age and substrate. Plant Ecology 44: 257-274. Information on wind disturbances and their effect on forest succession on Tutuila.

Whistler WA. 2004. Rainforest Trees of Samoa. Isle Botanica, Honolulu. A guide to the common lowland and foothill forest trees of the Samoan archipelago.

Whistler WA. 2002. The Samoan Rainforest. Isle Botanica, Honolulu. A guide to the various vegetation types of the Samoan archipelago, with some reference to landscape and soils, and based on extensive fieldwork.

Whistler WA. 1995. Wayside Plants of the Islands: A Guide to the Lowland Flora of the Pacific Islands. Isle Botanica, Honolulu. Reference of common introduced plant species in lowland areas of the Pacific Islands including American Samoa; with color photographs.

Whistler WA. 1994. Botanical Inventory of the Proposed Tutuila and Ofu Units of the National Park of American Samoa. Technical Report 87. National Park Service. Honolulu. Discussion of vegetation types within area of American Samoa National Park on Tutuila and Ofu.

Whistler WA. 1992. Botanical Inventory of the Proposed Ta`u Unit of the National Park of American Samoa. Technical Report 83. National Park Service. Honolulu. Discussion of vegetation types within area of American Samoa National Park on Ta`u.

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 Talbot

Approval

Kendra Moseley, 6/12/2025

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	06/13/2025
Approved by	Kendra Moseley
Approval date
Composition (Indicators 10 and 12) based on	Annual Production