Physiographic features

This ecological site occurs on lava flows on sloping mountainsides of shield volcanoes. Lava flows are aa (loose, cobbly) or pahoehoe (smooth, relatively unbroken).

Much of these lands were previously in pineapple and/or sugarcane and/or other crops.

Table 2. Representative physiographic features

Climatic features

(Unless otherwise cited, the information in this section is derived from Western Regional Climate Center, cited 2020).

Summary for this ecological site

Average annual precipitation in this ecological site ranges from 25 to 60 inches (625 to 1500 mm). Extremes of average annual precipitation may range as low as 15 inches (375 mm) and as high as 80 inches (2000 mm) and even up to 100 inches (2500 millimeters) on Kauai. In these extreme rainfall areas, the ecological site grades into associated ecological sites. Most of the precipitation occurs from October through April. Average annual temperatures range from 70 to 74 degrees F (21 to 23 degrees C). Conditions typically are dry. Rainfall occurs as light trade wind showers that drift over or around the mountains from the windward side of the islands and as heavier rainfall during major winter storms. Major storms are important for soil moisture recharge, and the number of major storms is highly variable; drought can result from a winter with few or no storms. Due to the latitude, daylength varies little during the year, resulting in only about a 50 percent variation in solar energy input between June maximum to December minimum; this variation is somewhat less than that found in the continental United States. Conditions are generally clear to lightly cloudy.

The Hoolehua plains on the windward side of west Molokai and the slopes on the north side of Lanai are subject to severe wind erosion by trade winds funneled between the highlands of east and west Molokai or through the channel between Molokai and Lanai. Sites near the ocean along the northern coast of west Maui are frequently windy, which can stunt vegetation or promote shrubland over forest.

General principles

Air temperature in the Hawaiian Islands is buffered by the surrounding ocean so that the range in temperature through the year is narrow. This creates “iso-“ soil temperature regimes in which mean summer and winter temperatures differ by less than 6 degrees C (11 degrees F).

Two seasons can be defined during the year: a winter season from October through April and a summer season from May through September. Summer has warmer temperatures, steadier and stronger trade winds, few widespread rainstorms, and generally lower average monthly rainfall than winter. The Kona Coast of Hawaii (the “Big Island”) is the only area where summer rainfall exceeds winter rainfall. Differences in rainfall amounts between winter and summer are most marked in low elevation dry areas; wetter areas exhibit less seasonal variation in rainfall.

The islands lie within the trade wind zone. Moisture is picked up from the ocean by trade winds to an altitude of about 6,000 feet (1850 meters). As the trade winds from the northeast are forced up the islands’ mountains their moisture condenses, creating rain on the windward slopes; the leeward sides of the island receive little of this moisture. The zones of highest rainfall on the windward flanks of the highest mountains (more than 10,000 feet or 3075 meters), which include Mauna Kea, Mauna Loa, and Haleakala, occur at elevations of 2,000 to 4,000 feet (615 to 1230 meters). A temperature inversion that fluctuates between about 5,000 and 7,000 feet (1540 to 2150 meters) on these three highest mountains creates a boundary between lower moist air and higher dry air. Above the inversion, rainfall is scant, skies are usually clear, humidity is low, and temperatures can drop below freezing. On West Maui, Kauai, Molokai, Oahu, and Lanai, where the mountains are all lower than 6,000 feet (1850 meters), the highest rainfall amounts occur along or near the summits. The moist trade winds usually flow across these lower mountains and around the higher mountains. Lanai is sheltered from the trade winds by the much larger island of Maui, putting it in a rain shadow during trade wind weather; rainfall on Lanai is uncharacteristically low for Hawaii.

Besides the trade winds discussed above, other rainfall sources on the Hawaiian Islands include: a) Widespread winter storms that usually approach the islands from the west, producing heavy rainstorms that primarily affect the leeward sides but can envelope much larger areas; b) "Naulu storms" (Leopold 1948) caused by local convergence of sea breezes and trade winds to produce summertime cumulus clouds, resulting in infrequent, short-duration, high-intensity rainfall and afternoon shade over leeward dry areas; and c) Fog drip, particularly important to areas with relatively low rainfall, that adds a significant amount of water to areas where clouds intersect mountains (Juvik and Nullet 1993; Western Regional Climate Center).

The heaviest rains are brought by winter storms. The greatest amounts of storm rainfall do not always occur in areas with the highest average rainfall, and a storm may bring half of the mean annual rainfall to a dry area in one day.

Table 3. Representative climatic features

Influencing water features

There are ephemeral streams that have formed gulches in this ecological site. These can flow strongly during and after rare heavy rainstorms. The gulches are partly vegetated with species typical of the rest of the ecological site.

Soil features

This extensive ecological site is correlated with many soil series and their phases that are classified in a variety of soil orders. However, most are related by certain factors. They are all well drained. They are in the moderately deep (20 to 40 inches or 50 to 100 centimeters), deep (40 to 60 inches or 100 to 150 centimeters), or very deep (deeper than 60 inches or 150 centimeters) classes; however, two soils are shallow (<20 inches or 50 centimeters). The soils formed in residuum or alluvium of basic igneous rock or in volcanic ash or volcanic ash plus tropospheric dust from Asia. The area is relatively old and weathered, as reflected in the soils mineralogy.

Surface soil pH ranges from 4.4 to 7.6; extreme pH of subsurface soils within 30 inches (75 centimeters) of the surface range from 4.6 to 7.5. These represent soil reaction (pH) that reflect parent materials and weathering. However, the Five Islands Soil Survey shows surface horizons of some soil series on Kauai, Oahu, Molokai, and Lanai as having unusually low pH in relation to subsurface horizons, degree of weathering, and/or parent materials. These series include Hamakuapoko (pH 4.0), Hoolehua (pH 3.9), Koele (pH 4.5), Kolekole (4.4), Kunia (4.3), Wahiawa (5.6), and Waihuna (5.3). The pHs of these soil series were measured in fields cultivated for pineapple, which was common when the survey was performed in the late 1960s to early 1970s; pHs of other soils that were measured under sugarcane or pasture do not exhibit such intense acidity. The natural pH, or pH under sugarcane agriculture or pasture, of these surface soils is likely 1 to 2 pH units higher. It is possible that surface pH has reverted to normal in the decades since pineapple cultivation ended. If planning to establish crops, forage, or trees on these soils or in areas known to have been cultivated for pineapple, a pH test is advisable.

Most of the soils have isohyperthermic (very warm) soil temperature regimes, although some are classified with isothermic (warm) soil temperature regimes. Based on available soil temperature data, these isothermic soils are in the warmer part of isothermic range, close to isohyperthermic temperatures. Almost all the soils have a soil moisture regime of ustic (in normal years, dry for more than 90 cumulative days but less than 180 days). A few are intergrades between ustic and aridic (in normal years, dry for more than half of the growing season and moist for less than 90 consecutive days during the growing season.

EWA, HALEIWA, KAWAIHAPAI, KEMOO, KOELE, MOKULEIA, PAIA, WAIALUA, AND WAIKOMO soils are classified as Mollisols. Many of the soils in very warm (mostly isohyperthermic, but sometimes isothermic), dry (torric, aridic, or ustic with aridic intergrade) areas of Hawaii are Mollisols or have mollic properties. Their key properties are a combination of a relatively thick, dark surface horizon (mollic epipedon) that does not become hard when dry, a dominance of calcium among the extractable cations, and a dominance of crystalline clay minerals of moderate or high cation-exchange capacity. These properties are conducive to plant growth. Although Mollisols usually form under grass in seasonally dry climates, they can form under a forest ecosystem. The original native vegetation here was likely dry forest.

Kawaihapai soils occur in stream valleys and alluvial fans on Oahu and Molokai; they are sometimes flooded when streams overflow their banks. Where it occurs at the mouths of Pelekunu and Wailau Valleys on Molokai, this soil receives more rainfall than is typical of the series. The phase of Koele series in this ecological site is Koele-Rocky complex; Koele soil occurs on about 30 to 50 percent of the area, and rocky gulches and knolls occupy the rest of the area. Mokuleia soils consist of recent clayey alluvium over coral sand. In places, it receives up to 100 inches (2500 centimeters) of annual rainfall. High temperatures and fast drainage in the sand layers likely keep water availability to plants within the typical range of this ecological site.

HALIIMAILE, HELEMANO, HOOLEHUA, KAHANA, KOLEKOLE, KUNIA, LAHAINA, LIHUE, MAHANA, POHAKUPU, and WAHIAWA soils are classified as Oxisols or have oxic properties. Oxisols are more highly weathered than other soils; they have a deep, subsurface oxic horizon dominated by clay-size particles of iron and aluminum hydrous oxides. Plant nutrients have been largely leached out of the soil. At low pH, phosphorus is adsorbed onto the oxides, making it largely unavailable to plants, and the ability to retain cation nutrients such as calcium, magnesium, and potassium against leaching is low. With the exception of more acidic Haliimaile soils, these Oxisols have subsurface soils with near neutral, neutral, or basic pH, which would counteract the more extreme problems of phosphorus fixation and low nutrient cation retention. Most of the soluble silica, which is an important element for grass tissue stability, has been leached out of these soils. Cementation of clay-sized minerals by iron oxides create a stable, well drained, workable soil, but the cemented, sand-like (pseudosand) particles often create droughty conditions as well. Maintenance of soil organic matter will counteract this characteristic.

Helemano soils can receive more annual rainfall than typical for this ecological site, but they occur on sides of gulches with steep slopes of 25 to 80 percent, which causes much of the extra rainfall to run off. Hoolehua soils occur in depressions and in drainageways. They receive less annual rainfall than other soils in this ecological site. However, they have a surface umbric horizon (thick, dark, high in organic matter) and they receive run-on water that improves their water availability status.

ALAELOA, HAMAKUAPOKO, IOLEAU, KALAE, KALAPA, and MANANA soils are classified as Humults, in the Ultisols soil order. The unique properties common to Ultisols are an argillic horizon (containing clay translocated from overlying horizons) and a low supply of bases, particularly in the lower horizons. The cation-exchange capacity in Ultisols is moderate or low. The decrease in base saturation with increasing depth reflects cycling of bases to the surface by plants or additions from fertilizers. In Ultisols that have not been cultivated, the highest base saturation is normally in the few centimeters directly beneath the surface. The clayey horizons can retain substantial amounts of water, much of it available to plants. Ultisols in the suborder Humults have at least 1.5 percent organic matter in the upper part of the argillic horizon, as defined in the 1972 Soil Survey. Ultisols tend to form in moist climates that promote weathering of soil materials and leaching of base cations, resulting in strongly to extremely acid soils. Many Ultisols in Hawaii are presently in seasonally dry climates; their ultic characteristics formed under wetter ancient climates.

The soil phase “Alaeloa stony silty clay, overwash, 15 to 35 percent slopes” (map unit ANE) occurs on toe slopes and in depressions where it has accumulated an overburden of stony silty clay loam that is 1 to 4 feet (25 to 100 centimeters) thick; it has stones and gravel throughout the soil profile. Erosion hazard is severe and gullies are common.

The soil phase “Kalapa very rocky silty clay, 40 to 70 percent slopes” (map unit KEHF) has 10 to 40 percent cover of rock outcrops. Manana soils have a nonporous panlike sheet that is 0.1 to 0.25 inch (about 3 to 6 millimeters) thick at a depth of about 15 inches (37 centimeters); this restrictive layer causes roots to form a mat.

KALAUPAPA and TANTALUS soils are Andisols. They are shallow (<20 inches or 50 centimeters), very rocky soils. They originally formed in volcanic ash (see next paragraph) and are old and weathered enough to exhibit characteristics of Andisols but not to have developed into other soil orders.

The volcanic ash soils of Hawaii are derived mostly from basaltic ash that varies relatively little in chemical composition (Hazlett and Hyndman 1996; Vitousek 2004). Most of these volcanic ash soils are classified today as Andisols, which have these general management characteristics: ion exchange capacity that varies with pH, but mostly retaining anions such as nitrate; high phosphorus adsorption, which restricts phosphorus availability to plants; excellent physical properties (low bulk density, good friability, weak stickiness, stable soil aggregates) for cultivation, seedling emergence, and plant root growth; resistance to compaction and an ability to recover from compaction following repeated cycles of wetting and drying; and high capacity to hold water that is available to plants. These characteristics are due to the properties of the parent material, the clay-size noncrystalline materials formed by weathering, and the soil organic matter accumulated during soil formation (Shoji et al. 1993).

KOKOKAHI, PAPAA, and WAIHUNA soils are Vertisols. Soils in this Order consist of shrinking-swelling clay that causes the soils to develop deep cracks when dry. Vertisols typically support grassland and savanna vegetation which may be have a more open canopy than typical for this ecological site; field work must be performed to determine if this is true. These soils are deep (40 to 60 inches or 100 to 150 centimeters). Unless affected by pineapple cultivation, their pH is slightly acid to neutral throughout. They are often rich in plant nutrient cations and soluble silica. The high clay content holds water tightly, so available water content is not high. The most extensive phase of Waihuna series is Waihuna clay, 0 to 3 percent slopes (map unit WoA). It occurs on Lanai. Small depressions in this soil phase are subject to ponding of adequately long duration to damage crops or interfere with farming operations.

HAWI and KOHALA soils are Inceptisols. Soils in this Order are characterized by having minimal horizon development in their profiles. Both soils formed in volcanic ash and in the underlying residuum. The upper horizons of both soils are thick and contain relatively high amounts of organic matter. They are dark, have strong or moderate structure, and can have fairly low base saturation.

Adjoining the soils described above are areas mapped as MISCELLANEOUS AREAS. By definition, they have little or no soil and support little or no vegetation. In the Five Islands Soil Survey upon which this ecological site is based, Miscellaneous Areas are extensive, and most and were mapped by low-intensity reconnaissance methods that provide less-detailed information than that presented for soil series and their phases. In many cases, however, Miscellaneous Areas in Maui, Molokai, Lanai, Oahu, and Kauai are moderately- to well-vegetated and/or contain plant and animal species of interest to conservationists. They are either extremely difficult to access or were not considered important enough at the time of this survey to warrant full expenditure of resources. They are described in the following paragraphs.

ROCK LAND (rRK) ROCK LAND (rRK) occurs on parent materials of basalt or andesite. Rock cover on the surface ranges from 25 to 90 percent; soils are very shallow (less than 10 inches or 25 centimeters). Near this ecological site it occurs mostly in gulches created by ephemeral streams. Vegetation is generally sparse, but in some spots, vegetation is dense due to localized accumulations of soil and extra moisture from seasonal stream flows. Common plant species are kiawe (Prosopis pallida), klu (Vachellia farnesiana), pili grass (Heteropogon contortus), uhaloa (Waltheria indica), and koa haole (Leucaena leucocephala).

ROCK OUTCROP (rRO) ROCK OUTCROP (rRO) has exposed bedrock covering more than ninety percent of the surface. Small areas of lithified coral sand occur on Kauai, Oahu, Lanai, and Molokai. Gulches on Kauai support sparse vegetation on steep sides and denser vegetation in gulch bottoms. Gulch sides on Maui, Molokai, and Lanai are sparsely vegetated; bottoms can be sparse or moderately vegetated.

ROUGH BROKEN LAND ( rRR) ROUGH BROKEN LAND (rRR) occurs on very steep sides of gulches and mountainsides. Soil amounts and characteristics are variable; beneath the soil is soft weathered rock. Most occurrences in the vicinity of this ecological site appear to support substantial vegetation cover. Common plant species are common guava (Psidium guajava), Natal redtop (Melinis repens), bermudagrass (Cynodon dactylon), koa haole (Leucaena leucocephala), and molassesgrass (Melinis minutiflora). Active soil erosion is common.

ROUGH BROKEN AND STONY LAND (rRS) ROUGH BROKEN AND STONY LAND (rRS) occurs on Maui in very steep, stony gulches. Some soil is present in variable amounts. It generally supports shrubs, small trees, and grass with a significant amount of bare ground.

STONY ALLUVIAL LAND (rSM) STONY ALLUVIAL LAND (rSM) consists of stones, boulders, and soil deposited by streams along bottoms of gulches and on alluvial fans. Much of it appears to be well vegetated, especially in gulch bottoms, although the driest gulch bottoms are sparsely vegetated. Common species are kiawe (Prosopis pallida), sweet acacia or klu (Acacia farnesiana), ilima (Sida cordifolia), pili (Heteropogon contortus), and lantana (Lantana camara).

STONY COLLUVIAL LAND (rSO) occurs on Molokai. It consists of talus slopes that are a mix of stones, boulders, and a small amount of soil material. It has slopes of 25 to 40 percent. This Miscellaneous Area is typically fully vegetated with christmasberry (Schinus terebinthifolius), koa haole (Leucaena leucocephala), kukui (Aleurites moluccanus), and Java plum (Syzygium cumini).

BLOWN-OUT LAND (BW) occurs mainly on the windswept northern plateau of Lanai. It is mostly barren of vegetation and eroded down to compact subsoil or soft weathered rock. About 10 percent of the area is hummocks or small dunes that support dallisgrass (Paspalum dilatatum), molassesgrass (Melinis minutiflora), bermudagrass (Cynodon dactylon), and ilima (Sida fallax). Strong winds are common. Soil tests show this land to be low in plant nutrients.

Table 4. Representative soil features

Table 5. Representative soil features (actual values)

Inventory data references

1. Hawaii county, Hawaii:
a. North Kohala District. 20.13.38 N Latitude, 155.52.43 W Longitude (degrees.minutes.seconds). USGS
Quad: Mahukona. Parker Ranch -- 2.5 miles north of turnoff to Kapaa County Beach Park on State Route 270. Located 0.5 miles southwest, on unpaved ranch road on east side of highway. Pasture on south side of unpaved
ranch road.
b. North Kohala District. 20.16.41 N Latitude, 155.51.38 W Longitude (degrees.minutes.seconds). USGS Quad: Hawi. Boteilho Lease -- 1.9 miles north on paved road from State Route 270 that leads to the Upolu Airport. In pasture on west side of paved road.

2. Maui County, Hawaii:
a. Maui county, Island of Maui. Finalized type location not established.
b. Maui county, Island of Molokai. Finalized type location not established.

3. Honolulu County, Island of Oahu. Finalized type location not established.

4. Kauai County, Island of Kauai. Finalized type location not established.

Other references

Definitions
These definitions have been greatly simplified for brevity and do not cover every aspect of each topic.

Aa lava: A type of basaltic lava having a rough, jagged, clinkery surface and a vesicular interior.

Alluvial: Materials or processes associated with transportation and/or deposition by running water.

Aquic soil moisture regime: A regime in which the soil is free of dissolved oxygen because it is saturated by water. This regime typically exists in bogs or swamps.

Aquisalids: These are salty soils in wet areas. Although wet, the dissolved salts make the soils physiologically dry (the chemical activity, or effective concentration, of water is low). Aquisalids typically support plant species that are adapted to these conditions.

Aridic soil moisture regime: A regime in which defined parts of the soil are, in normal years, dry for more than half of the growing season and moist for less than 90 consecutive days during the growing season. In Hawaii it is associated with hot, dry areas with plants such as kiawe, wiliwili, and buffelgrass. The terms aridic and torric are basically the same.

Ash field: a land area covered by a thick or distinctive deposit of volcanic ash that can be traced to a specific source and has well defined boundaries. The term “ash flow” is erroneously used in the Physiographic section of this ESD due to a flaw in the national database.

Ashy: A “soil texture modifier” for volcanic ash soils having a water content at the crop wilting point of less than 30 percent; a soil that holds relatively less water than “medial” and “hydrous” soils.

Available water capacity: The amount of soil water available to plants to the depth of the first root-restricting layer.

Basal area or basal cover: The cross sectional area of the stem or stems of a plant or of all plants in a stand.

Blue rock: The dense, hard, massive lava that forms the inner core of an aa lava flow.

Bulk density: the weight of dry soil per unit of volume. Lower bulk density indicates a greater amount of pore space that can hold water and air in a soil.

CaCO3 equivalent: The amount of free lime in a soil. Free lime exists as solid material and typically occurs in regions with a dry climate.

Canopy cover: The percentage of ground covered by the vertical projection downward of the outermost perimeter of the spread of plant foliage. Small openings within the canopy are included.

Community pathway: A description of the causes of shifts between community phases. A community pathway is reversible and is attributable to succession, natural disturbances, short-term climatic variation, and facilitating practices, such as grazing management.

Community phase: A unique assemblage of plants and associated dynamic soil properties within a state.

Dominant species: Plant species or species groups that exert considerable influence upon a community due to size, abundance, or cover.

Drainage class: The frequency, duration, and depth of a water table in a soil. There are seven drainage classes, ranging from “excessively drained” (soils with very rare or very deep water tables) to “well drained” (soils that provide ample water for plant growth but are not so wet as to inhibit root growth) to “very poorly drained” (soils with a water table at or near the surface during much of the growing season that inhibits growth of most plants).

Electrical conductivity (EC): A measure of the salinity of a soil. The standard unit is deciSiemens per meter (dS/m), which is numerically equivalent to millimhos per centimeter (mmhos/cm). An EC greater than about 4 dS/m indicates a salinity level that is unfavorable to growth of most plants.

Friability: A soil consistency term pertaining to the ease of crumbling of soils.

Gleyed: A condition of soil from which iron has been reduced (in the redox chemistry sense) and removed during soil formation or that saturation with stagnant water has preserved a reduced state. If iron has been removed, the soil is the color of uncoated sand and silt particles. If iron is present in a reduced state, the soil is the color of reduced iron (typically bluish-gray). Redox concentrations (spots of oxidized iron, formerly called mottles are often present.

Hydrous: A “soil texture modifier” for volcanic ash soils having a water content at the crop wilting point of 100 percent or more; a soil that holds more water than “medial” or “ashy” soils.

Ion exchange capacity: The ability of soil materials such as clay or organic matter to retain ions (which may be plant nutrients) and to release those ions for uptake by roots.

Isohyperthermic soil temperature regime: A regime in which mean annual soil temperature is 72 degrees F (22 degrees C) or higher and mean summer and mean winter soil temperatures differ by less than 11 degrees F (6 degrees C) at a specified depth.

Isomesic soil temperature regime: A regime in which mean annual soil temperature is 47 degrees F (8 degrees C) or higher but lower than 59 degrees F (15 degrees C) and mean summer and mean winter soil temperatures differ by less than 11 degrees F (6 degrees C) at a specified depth.

Isothermic soil temperature regime: A regime in which mean annual soil temperature is 59 degrees F (15 degrees C) or higher but lower than 72 degrees F (22 degrees C) and mean summer and mean winter soil temperatures differ by less than 11 degrees F (6 degrees C) at a specified depth.

Kipuka: An area of land surrounded by younger (more recent) lava. Soils and plant communities within a kipuka are older than, and often quite different from, those on the surrounding surfaces.

Major Land Resource Area (MLRA): A geographic area defined by NRCS that is characterized by a particular pattern of soils, climate, water resources, and land uses. The island of Hawaii contains nine MLRAs, some of which also occur on other islands in the state.

Makai: a Hawaiian word meaning “toward the sea.”

Mauka: a Hawaiian word meaning “toward the mountain” or “inland.”

Medial: A “soil texture modifier” for volcanic ash soils having a water content at the crop wilting point of 30 to 100 percent; a soil that holds an amount of water intermediate to “hydrous” or “ashy” soils.

Mollisols: Soils with relatively thick, dark surface horizons, high cation-exchange capacity, high calcium content, that do not become hard or very hard when dry. Mollisols are conducive to plant growth. They characteristically form under grass in climates that are seasonally dry, but can form under forests.

Naturalized plant community: A community dominated by adapted, introduced species. It is a relatively stable community resulting from secondary succession after disturbance. Most grasslands in Hawaii are in this category.

Oxisols: Soils characteristic of humid, tropical or subtropical regions that formed on land surfaces that have been stable for a long time. In Hawaii, they typically occur on islands or parts of islands that have been volcanically inactive for a long time. Oxisols are highly weathered, consist largely of quartz, kaolin clays, and aluminum oxides, and have low ion exchange capacity and loamy or clayey texture.

Pahoehoe lava: A type of basaltic lava with a smooth, billowy, or rope-like surface and vesicular interior.

Parent material: Unconsolidated and chemically weathered material from which a soil is developed.

Perudic soil moisture regime: A very wet regime found where precipitation exceeds evapotranspiration in all months of normal years. On the island of Hawaii, this regime is found on top of Kohala and on parts of the windward side of Mauna Kea.

pH: The numerical expression of the relative acidity or alkalinity of a soil sample. A pH of 7 is neutral; a pH below 7 is acidic and a pH above 7 is basic.

Phosphorus adsorption: The ability of soil materials to tightly retain phosphorous ions, which are a plant nutrient. Some volcanic ash soils retain phosphorus so strongly that it is partly unavailable to plants.

Psamments: Sandy soils that have low water-holding capacity, are susceptible to wind erosion, and typically have ground water deeper than 20 inches (50 centimeters).

Reference community phase: The phase exhibiting the characteristics of the reference state and containing the full complement of plant species that historically occupied the site. It is the community phase used to classify an ecological site.

Reference state: A state that describes the ecological potential and natural or historical range of variability of an ecological site.

Residuum: Unconsolidated mineral material that has chemically and physically weathered from rock and has not moved from its place of origin.

Restoration pathway: A term describing the environmental conditions and practices that are required to recover a state that has undergone a transition.

Sodium adsorption ratio (SAR): A measure of the amount of dissolved sodium relative to calcium and magnesium in the soil water. SAR values higher than 13 create soil conditions unfavorable to most plants.

Soil moisture regime: A term referring to the presence or absence either of ground water or of water held at a tension of less than 1500 kPa (the crop wilting point) in the soil or in specific horizons during periods of the year.

Soil temperature regime: A defined class based on mean annual soil temperature and on differences between summer and winter temperatures at a specified depth.

Soil reaction: Numerical expression in pH units of the relative acidity or alkalinity or a soil.

Spodosols: Soils with a spodic B horizon that has an accumulation of black or reddish amorphous materials that have a high pH-dependent ion exchange capacity, coarse texture, and few base cations. Above the spodic horizon there often is a light-colored albic horizon that was the source of the amorphous materials in the spodic horizon.

State: One or more community phases and their soil properties that interact with the abiotic and biotic environment to produce persistent functional and structural attributes associated with a characteristic range of variability.

State-and-transition model: A method used to display information about relationships between vegetation, soil, animals, hydrology, disturbances, and management actions on an ecological site.

Torric soil moisture regime: See Aridic soil moisture regime.

Transition: A term describing the biotic or abiotic variables or events that contribute to loss of state resilience and result in shifts between states.

Udic soil moisture regime: A regime in which the soil is not dry in any part for as long as 90 cumulative days in normal years, and so provides ample moisture for plants. In Hawaii it is associated with forests in which hapuu (tree ferns) are usually moderately to highly abundant.

Ultisols: Soils that have been intensively leached and weathered. They have a B horizon that has accumulated clay that has translocated there from higher horizons. They have moderate to low cation exchange capacity and low base saturation. The highest base saturation normally is in the few centimeters directly beneath the surface due to cycling of bases by plants.

Ustic soil moisture regime: A regime in which moisture is limited but present at a time when conditions are suitable for plant growth. In Hawaii it usually is associated with dry forests and subalpine shrublands.

Other References

Abrahamson I. 2013. Fire regimes in Hawaiian plant communities. In: Fire Effects Information System, US Dept. of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Available" www.fs.fed.us/database/feis/fire_regimes/Hawaii/all.html

Allen, M.S., 2014. Marquesan colonization chronologies and post-colonization interaction: implications for Hawaiian origins and the ‘Marquesan Homeland’ hypothesis. Journal of Pacific Archaeology, 5(2), pp.1-17.

Armstrong RW. 1973. Atlas of Hawaii. University of Hawaii Press, Honolulu.

Athens JS. Ch. 12 Hawaiian Native Lowland Vegetation in Prehistory in Historical Ecology in the Pacific Islands – Prehistoric Environmental and Landscape Change. Kirch, PV and TL Hunt, eds. 1997. Yale U. Press, New Haven.

Burney DA, HF James, LP Burney, SL Olson, W Kikuchi, WL Wagner, M Burney, D McCloskey, D Kikuchi, FV Grady, R Gage II, and R Nishek. 2001. Fossil evidence for a diverse biota from Kauai and tis transformation since human arrival. Ecological Monographs 71:615-641.

Christensen CC. 1983. Report 17: Analysis of land snails. In: Archaeological investigations of the Mudlane-Waimea-Kawaihae Road Corridor, Island of Hawaii: An Interdisciplinary Study of an Environmental Transect. Clark JT. and Kirch PV, eds. Dept. of Anthropology, Bernice Pauahi Bishop Museum, Report 83-1, Honolulu, HI.

Clark JT. 1983. Report 3: The Waimea-Kawaihae Region: Historical Background. In: Archaeological investigations of the Mudlane-Waimea-Kawaihae Road Corridor, Island of Hawaii: An Interdisciplinary Study of an Environmental Transect. Clark JT and Kirch PV, eds. Dept. of Anthropology, Bernice Pauahi Bishop Museum, Report 83-1, Honolulu, HI.

Clark JT. 1983. Report 7: Archaeological investigations in Section 4. In: Archaeological investigations of the Mudlane-Waimea-Kawaihae Road Corridor, Island of Hawaii: An Interdisciplinary Study of an Environmental Transect. Clark JT and Kirch PV, eds. Dept. of Anthropology, Bernice Pauahi Bishop Museum, Report 83-1, Honolulu, HI.

Clark JT. 1983. Report 8: Archaeological investigations of agricultural sites in the Waimea area. In: Archaeological investigations of the Mudlane-Waimea-Kawaihae Road Corridor, Island of Hawaii: An Interdisciplinary Study of an Environmental Transect. Clark JT and Kirch PV, eds. Dept. of Anthropology, Bernice Pauahi Bishop Museum, Report 83-1, Honolulu, HI.

Craighill ES and EG Handy. 1991. Native Planters in Old Hawaii – Their Life, Lore, and Environment. Bernice P. Bishop Museum Bulletin 233, Bishop Museum Press, Honolulu, HI

Cuddihy LW and CP Stone. 1990. Alteration of Native Hawaiian Vegetation: Effects of Humans, Their Activities and Introductions. Honolulu: University of Hawaii Cooperative National Park Resources Study Unit.

Deenik J and AT McClellan. 2007. Soils of Hawaii. Soil and Crop Management, Sept. 2007, SCM-20. Cooperative Extension Service, College of Tropical Agriculture and Human Resources. University of Hawaii at Manoa. Available online at: https://www.ctahr.hawaii.edu/oc/freepubs/pdf/SCM-20.pdf

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

Giambelluca TW and TA Schroeder. 1998. Climate. In: Atlas of Hawaii, 3rd edition. SP Juvik, JO Juvik, and RR Paradise, eds. pp. 49-59. Honolulu: University of Hawaii Press.

Gil CR. 2016-2017. Ananas comosus. Colegio Bolivar Agricultural Science. Available online at: https://www.colegiobolivar.edu.co/garden/wp-content/uploads/2017/06/Crosas-Ananas-comosus-2017.pdf

Hazlett RW and DW Hyndman. 1996. Roadside Geology of Hawaii. Mountain Press Publishing Company, Missoula MT.

Henke LA. 1929. A Survey of Livestock in Hawaii. Research Publication No. 5. University of Hawaii, Honolulu.

Horrocks M. 2009. Sweet potato (Ipomoea batatas) and banana (Musa sp.) microfossils in deposits from the Kona Field System, Island of Hawaii. Journal of Archaeological Science, May 2009.

Imada, C. 2012. Hawaiian Native and Naturalized Vascular Plants Checklist (December 2012 update). Bishop Museum Technical Report 60. Bishop Museum Press, Honolulu.

Jacobi JD. 1989. Vegetation Maps of the Upland Plant Communities on the Islands of Hawaii, Maui, Molokai, and Lanai. Technical Report 68. Cooperative National Park Resources Studies Unit, University of Hawaii at Manoa and National Park Service.

Juvik JO and D Nullet. 1993. Relationships between rainfall, cloud-water interception, and canopy throughfall in a Hawaiian montane forest. IN: Tropical Montane Cloud Forests. Proc. Int. Sym., San Juan, PR. Hamilton LS, JO Juvik, and FN Scatena, eds. East-West Center.

Kirch PV. 1982. The impact of the prehistoric Polynesians in the Hawaiian ecosystem. Pacific Science 36(1):1-14.

Kirch PV. 1983. Introduction. In: Archaeological investigations of the Mudlane-Waimea-Kawaihae Road Corridor, Island of Hawaii: An Interdisciplinary Study of an Environmental Transect. Clark JT and Kirch PV, eds. Dept. of Anthropology, Bernice Pauahi Bishop Museum, Report 83-1, Honolulu, HI.

Kirch PV. 1985. Feathered Gods and Fishhooks: An Introduction to Hawaiian Archaeology and Prehistory. Honolulu: University of Hawaii Press.

Kirch PV. 2000. On the Road of the Winds: An Archaeological History of the Pacific Islands Before European Contact. Berkeley: University of California Press.

Kirch, P.V., 2011. When did the Polynesians settle Hawaii? A review of 150 years of scholarly inquiry and a tentative answer. Hawaiian Archaeology, 12(2011), pp.3-26.

Leopold LB. 1949. The interaction of trade wind and sea breeze, Hawaii. Journal of Meteorology 6: 312-320.

Little EL Jr. and RG Skolmen. 1989. Common Forest Trees of Hawaii (Native and Introduced). US Department of Agriculture-US Forest Service Agriculture Handbook No. 679. (out of print). Available at www.fs.fed.us/psw/publications/documents/misc/ah679.pdf

Maly K and O Maly. 2004. He Moolelo Aina: A Cultural Study of the Puu O Umi Natural Area Reserve and Kohala-Hamakua Mountain Lands, Districts of Kohala and Hamakua, Island of Hawaii. Kumu Pono Associates, Hilo HI.

McEldowney H. 1983. Report 16: A description of major vegetation patterns in the Waimea-Kawaihae region during the early historic period. In: Archaeological investigations of the Mudlane-Waimea-Kawaihae Road Corridor, Island of Hawaii: An Interdisciplinary Study of an Environmental Transect. Clark JT and Kirch PV, eds. Dept. of Anthropology, Bernice Pauahi Bishop Museum, Report 83-1, Honolulu, HI.

Mubyana T. 1997/98. Effects of continuous sugarcane and pineapple cropping on organic matter and soil microbial biomass. Journal of African Research and Development 27&28:258-269.

Mueller-Dombois D and FR Fosberg. 1998. Vegetation of the Tropical Pacific Islands. Springer-Verlag New York, Inc.

Palmer DD. 2003. Hawaii’s Ferns and Fern Allies. University of Hawaii Press, Honolulu.

Pratt HD. 1998. A Pocket Guide to Hawaii’s Trees and Shrubs. Mutual Publishing, Honolulu.

Reppun F, Silva JHS, Wong K, and Deenik JL. 2017. A Soil Phosphorus Primer for Hawaiian Soils. Soil and Crop Management, August 2017, SCM-33. College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa. Available online at: https://www.ctahr.hawaii.edu/oc/freepubs/pdf/SCM-33.pdf

Ripperton JC and EY Hosaka. 1942. Vegetation zones of Hawaii. Hawaii Agricultural Experiment Station Bulletin 89:1-60.

Rock JF. The Indigenous Trees of the Hawaiian Islands. 1st edition 1913, reprinted 1974, Charles E. Tuttle Company, Rutland, VT and Tokyo, Japan.

Schroeder TA. 1981. Characteristics of local winds in northwest Hawaii. Journal of Applied Meteorology 20: 874-881.

Shoji SD, M Nanzyo, and R Dahlgren. 1993. Volcanic Ash Soils: Genesis, Properties and Utilization. Elsevier, New York.

Silva JA and R Uchida, eds. 2000. Plant Nutrient Management in Hawaii’s Soils, Approaches for Tropical and Subtropical Agriculture. College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa. Available online at: https://www.ctahr.hawaii.edu/oc/freepubs/pdf/pnm0.pdf

Sohmer SH and R Gustafson. 2000. Plants and Flowers of Hawaii. University of Hawaii Press, Honolulu.

Soil Survey Staff. 2014. Soil Taxonomy, Twelfth Edition. USDA – NRCS.

Steadman DW. 1995. Prehistoric extinctions of Pacific island birds: biodiversity meets zooarchaeology. Science 267:1123-1131.

USDA-NRCS-PIA T&E Species GIS files. Not publicly available.

USDA-NRCS. 2011. Soil Survey Laboratory Information Manual. Soil Survey Investigations Report No. 45, Version 2.0. National Soil Survey Center, Lincoln, Nebraska.

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

USDA-NRCS. Island of Hawaii Soil Surveys 801 and 701. Available online at https://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm

USDA-SCS. 1972. Soil Survey of Islands of Kauai, Oahu, Maui, Molokai, and Lanai, State of Hawaii. Foote DE, Hill EL, Nakamura S, and F Stephens, in cooperation with The University of Hawaii Agricultural Experiment Station.

USDI-USGS. 2006. A GAP Analysis of Hawaii. Final Report and Data.

Vitousek P. 2004. Nutrient Cycling and Limitation: Hawaii as a Model Ecosystem. Princeton University Press, Princeton and Oxford.

Wagner WL, DR Herbst, and SH Sohmer. 1999. Manual of the Flowering Plants of Hawaii, Revised Edition. Bishop Museum Press, Honolulu.

Welch DJ 1983. Report 5: Archaeological investigations in Section 2. In: Archaeological investigations of the Mudlane-Waimea-Kawaihae Road Corridor, Island of Hawaii: An Interdisciplinary Study of an Environmental Transect. Clark JT and Kirch PV, eds. Dept. of Anthropology, Bernice Pauahi Bishop Museum, Report 83-1, Honolulu, HI.

Western Regional Climate Center, cited 2020. Climate of Hawaii. Available at: https://wrcc.dri.edu/Climate/narrative_hi.php

Whistler WA. 1995. Wayside Plants of the Islands: A Guide to the Lowland Flora of the Pacific Islands. Isle Botanica, Honolulu.

Wilmshurst, J.M., Hunt, T.L., Lipo, C.P. & Anderson, A.J. 2011. High-precision radiocarbon dating shows recent and rapid initial human colonization of East Polynesia. Proceedings of the National Academy of Sciences, USA, 108:1815–1820.

Contributors

Joseph May
Loretta J. Metz
David Clausnitzer
John Proctor
Carolyn Wong
Mathew Cocking
Amy Koch
Kendra Moseley
Jennifer Higashino
Mike Kolman

Approval

Kendra Moseley, 4/17/2025

Acknowledgments

Assistance, advice, review, and/or insights:

Elena Dosamantes, NRCS
John Colon, NRCS
David Duvauchelle, NRCS
Richard Ogoshi, NRCS
Kip Dunbar, Dunbar Ranch
Butch Hasse, Director Molokai Land Trust,
Hanohano Naehu, Fish pond guardian at Keawanui
Brian Carvillio, Mahi Pono
Randy Bartlett, Puu Kukui Watershed Preserve
Alison Cohan, The Nature Conservancy
Michael Constantinides, NRCS-PIA
Gordon Cran, Kapapala Ranch
Diana Crow, Ulupalakua Ranch
Lance DeSilva, Hawaii DLNR
Kerri Fay, Waikamoi Preserve, The Nature Conservancy
Alex Franco, Kaupo Ranch
Ranae Ganske-Cerizo, NRCS
Carl Hashimoto, NRCS
Bob Hobdy, consultant, Maui
Wallace Jennings, NRCS
Mel Johansen, The Nature Conservancy
Jordan Jokiel, Haleakala Ranch
David Leonard, volunteer
Penny Levin
Reese Libby, GIS - NRCS
Hannah Lutgen, Maui SWCD
Joseph May, NRCS
Scott Meidel, Haleakala Ranch
Anna Palomino, Hoolawa Farms Inc.
Jon Price, USGS
Tamara Sherrill, USFWS, Maui Nui Botanical Garden
Amber Starr, Hana Ranch
Kahana Stone, NRCS
Mark Vaught, Water Resources, Alexander & Baldwin
Jacqueline Vega, NRCS
Rich von Wellsheim, Whispering Bamboos, Kipahulu