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Ecological site VX167X01X001
Oxidic Dissected Lowland
Last updated: 5/08/2025
Accessed: 10/02/2026
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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): 167X–Humid Oxidic Soils on Low and Intermediate Rolling Mountain Slopes
This MLRA occurs in the State of Hawaii on the windward, wetter sides of the islands of Kauai, Oahu, and Maui. Elevation ranges from near sea level to 2,000 feet (0 to 610 meters) with extremes up to 3,100 feet (0 to 945 meters). Topography is rolling mountain slopes that have been eroded by steep-sided gulches. In most of the area, volcanic ash is underlaid by basic igneous rocks, although in some areas volcanic ash was deposited over cinders (USDA-NRCS, 2006). In other areas alluvial sediments occur on bottom lands and low terraces along streams. In some small areas, the dominant geology is influenced by tropospheric dust. Average annual precipitation in most of the area ranges from 50 to 114 inches (1,270 to 2,896 millimeters); extremes range from 20 inches to 247 inches (508 to 6,274 millimeters) (Giambelluca et al., 2013). Rainfall is well-distributed throughout the year with an enhanced rainy season from November through April. Average annual air temperatures range from 72 to 77 degrees F (22 to 25 degrees C); extremes range from 61 to 82 degrees F (16 to 28 degrees C) (Giambelluca et al., 2014). The dominant soil orders are Ultisols, Oxisols, Inceptisols, and Andisols with isohyperthermic and isothermic temperature regimes and ustic, udic, and occasionally perudic soil moisture regimes (USDA-NRCS, 2006). Native vegetation consists of medium to tall statured rain forest and open bogs.
Classification relationships
This ecological site occurs within Major Land Resource Area (MLRA) 167 - Humid Oxidic Soils on Low and Intermediate Rolling Mountain Slopes.
The Aha Moku System, which dates back to the 9th century and has been passed down through oral tradition and generational wisdom, effectively sustains Hawaii's natural ecosystems and environment (DLNR, 2024). This site-specific and resource-based approach balances land and ocean resources essential for fostering healthy, thriving communities. Grounded in Native Hawaiian generational knowledge, the Aha Moku System emphasizes community consultation to prioritize the health and welfare of Hawaii's natural and cultural resources. It is rooted in the concept of 'ahupua'a, the traditional system of land and ocean management in Hawaii. For collaboration, this ecological framework encompasses the following mokus:
Moku Acres on Kauai: Puna (23,292), Halele'a (11,322), Kona (7,323), Ko'olau (5,274), and Napali (508).
Moku Acres on Maui: Hamakualoa (14,355), Ko'olau (3,099), and Hamakuapoko (1,452).
Moku Acres on Oahu: Ko'olauloa (24,374), Ko'olaupoko (14,583), Kona (5,157), Waialua (185), Wai'anae (557), and Ewa (11).Ecological site concept
This ecological site is situated on the north-central coast of East Maui, the northeastern coast of Oahu, and the northern and eastern sides of Kauai. It occurs largely on flat interfluves between numerous gulches, and ranges from 0 to 1,000 feet (0 to 305 meters) with extremes up to 3,100 feet (945 meters) elevation on Maui. Much of the land is in private ownership. The public road network provides access to most of the ecological site. Most of the area is used for crops, livestock grazing, residential development, or is in forests consisting mostly of introduced species (USDI-USGS, 2006).
The central concept of the Oxidic Dissected Lowland is of well drained, deep, and very deep soils formed in highly weathered volcanic materials. Soils are mostly in the Ultisols and Oxisols orders, with low pH, low base saturation, and clay-sized minerals that sequester phosphorus and have pH-dependent ion exchange properties. Annual air temperatures and rainfall are associated with very warm (isohyperthermic to warm isothermic), moist (moist ustic to udic) soil conditions (USDA-SCS, 1972). The most common introduced grass is guineagrass (Urochloa maxima), although para grass or Californiagrass (Urochloa mutica) is abundant in wetter parts of the ecological site. Forested areas contain many introduced species, with strawberry guava (Psidium cattleianum), Java plum (Syzygium javanicum), and African tulip-tree (Spathodea campanulata) among the more common species. White leadtree or koa haole (Leucaena leucocephala) is common in drier extremes, while Brazilian peppertree or christmasberry (Schinus terebinthifolius) is common in areas that define the central concept. Remaining native trees include 'ohi'a lehua (Metrosideros polymorpha) and Tahitian screw pine or hala (Pandanus tectorius), among other (Wagner et al., 1999).Associated sites
VX158X01X401 Isohyperthermic Ustic Naturalized Grassland Koa haole/guineagrass/glycine (Leucaena leucocephala/Urochloa maxima/Neonotonia wightii)
The Isohyperthermic Ustc Naturalized Grassland Ecological Site (R158XY401HI) adjoins this ecological site on Kauai, Oahu, and Maui. It has the same soil temperature regime as this ecological site but a drier soil moisture regime. It is correlated with some highly weathered soils similar to those in this ecological site but, in general, has soils that are less weathered. It supports typical native Hawaiian dry forest to transitional dry-to-moist forest rather than lowland rainforest. Guineagrass rather than para grass is the main forage species in R158XY401HI, while there is para grass in the wetter parts of R167XY001HI.
VX158X01X005 Naturalized Grassland 50 to 90 inch PZ Ohia lehua/kikuyugrass (Metrosideros polymorpha/Pennisetum clandestinum)
The Naturalized Grassland 50 to 90 Inch Precipitation Zone Ecological Site (R158XY005HI) adjoins this ecological site on Kauai and, to very small extents, Oahu and Maui. It has a warmer and drier climate than this ecological site (but cooler and moister than R158XY401HI in the above row) and has similarly highly weathered soils to the soils in this ecological site. Native vegetation is
VX167X01X002 Flooded Alluvium
The Flooded Alluvium Ecological Site (R167XY002HI) adjoins this ecological site on Kauai and Oahu. It occurs on active floodplains along streams that dissect the uplands upon which this ecological site occurs. Climate is identical for these two sites, but R167XY002HI receives additional water during flooding and largely occurs on somewhat poorly to poorly drained soils in contrast with the moderately well and well drained soils of this ecological site.
VX164X01X002 Organic Surface Forest
The Organic Surface Forest Ecological Site (F164XY002HI) adjoins this ecological site on Maui. It receives more rainfall and in part has cooler temperatures than this ecological site. It has well drained soils and supports higher-elevation rainforest than this ecological site, with higher species diversity and wider occurrence of koa trees.
VX164X01X004 Epiaquic Forest
The Epiaquic Forest Ecological Site (F164XY004HI) adjoins this ecological site on Kauai. It occurs mostly at higher elevations with cooler and wetter climate than this ecological site. F164XY004HI has soils with shallow ironstone sheets that cause a perched water table and poorly drained conditions, unlike the moderately well and well drained conditions of this ecological site. It supports stunted rainforest interspersed with open bogs rather than lowland rain forest.
VX160X01X007 Isothermic Ustic Naturalized Grassland (Kikuyugrass)
The Isothermic Ustic Naturalized Grassland Ecological Site (R160XY007HI) adjoins this ecological site on Maui. It occurs at mostly higher elevations with cooler and drier climate and less weathered soils than this ecological site. It would have supported a drier native forest dominated by koa and ohia lehua. The dominant forage species are guineagrass, kikuyugrass, and cool-season grasses rather than para grass.
Table 1. Dominant plant species
Tree (1) Metrosideros polymorpha
(2) Pandanus tectoriusShrub Not specified
Herbaceous (1) Urochloa maxima
(2) DesmodiumLegacy ID
R167XY001HI
Physiographic features
This ecological site occurs on lava flows, alluvial fans, and terraces on the sloping mountainsides of shield volcanoes. Lava flows are aa (loose, cobbly) or pahoehoe (smooth, relatively unbroken) (USDA-SCS, 1972).
Table 2. Representative physiographic features
Landforms (1) Shield volcano > Lava flow
(2) Shield volcano > Alluvial fan
(3) Shield volcano > Terrace
(4) Shield volcano > Mountain slope
Runoff class Low to high Flooding frequency None Ponding frequency None Elevation 0 – 1000 ft Slope 0 – 70 % Water table depth 72 in Aspect N, NE, E Table 3. Representative physiographic features (actual ranges)
Runoff class Low to very high Flooding frequency Not specified Ponding frequency Not specified Elevation 0 – 3100 ft Slope 0 % Water table depth 0 in Climatic features
Summary for this ecological site
Rainfall statistics were determined from University of Hawaii's Rainfall Atlas Raster Data (Giambelluca et al., 2013). Most of the precipitation falls from October through April. Representative (20th and 80th percentiles) values for annual average precipitation range from 68 to 114 inches (1,727 to 2,896 millimeters) while actual (10th and 90th percentiles) values for annual average precipitation range from 60 to 137 inches (1,524 to 3,478 millimeters). Extreme values range from 36 to 247 inches (914 to 6,274 millimeters). The mean annual precipitation is 93 inches (2,362 millimeters) and the median annual average precipitation is 85 inches (2,159 millimeters).
Temperature statistics were determined from University of Hawaii's Surface Temperature Raster Data (Giambelluca et al., 2014). Representative (20th and 80th percentiles) values for annual temperatures range from 70 to 75 degrees F (21 to 24 degrees C) while actual (10th and 90th percentiles) values for annual temperatures also range from 70 to 75 degrees F (21 to 24 degrees C). Extreme values range from 61 to 81 degrees F (16 to 27 degrees C). The mean annual temperature is 72 degrees F (22 degrees C) and the median annual temperature is also 72 degrees F (22 degrees C).
The data presented in the climate normals tables below are from the Western Region Climate Center (Western Regional Climate Center, 2020). The available climate station data are most representative of the moderate precipitation areas of this ecological site. I used these data because they provide a reasonable approximation of the University of Hawaii data presented above.
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 "so" - soil temperature regimes in which mean summer and winter temperatures differ by less than 6 degrees C (11 degrees F).
Hawaiian indigenous understanding recognized two seasons: Kau or Kauwela (dry season), and Ho`oilo (wet season). During Kau, the sun is directly overhead, days are long and warm, and the trade winds are stronger and more consistent; Kau started on the first new moon in May when the Pleiades set at sunrise (Handy et al., 1991). During Ho’oilo (wet season) the sun is declined toward the south, days are shorter, temperatures cooler and winds more variable and generally started with the first new moon in November. Ho’oilo is also the season when extensive low-pressure systems often approach the islands from the west, producing heavy rainstorms that primarily affect the leeward sides, but can envelope the entire island. (Malo, 1903; Handy et al., 1991; Sanderson, 1993). Differences in rainfall amounts between winter and summer are most marked in low elevation dry areas; wetter areas exhibit less seasonal variation in rainfall (USDA-SCS, 1972; Western Regional Climate Center, 2020).
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 (1,829 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 3,048 meters), which include Mauna Kea, Mauna Loa, and Haleakala, occur at elevations of 2,000 to 4,000 feet (610 to 1,219 meters). A temperature inversion that fluctuates between about 5,000 and 7,000 feet (1,524 to 2,134 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 (USDA-SCS, 1972; Western Regional Climate Center, 2020).
On Kauai and Lanai, where the mountains are all lower than 6,000 feet (1,829 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 (USDA-SCS, 1972).
Besides the trade winds discussed above, other rainfall sources on the Hawaiian Islands include: a) "Naulu storms" (Leopold, 1949) 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 b) 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, 2020).
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 (USDA-SCS, 1972; Western Regional Climate Center, 2020).Table 4 Representative climatic features
Frost-free period (characteristic range) 370 days Freeze-free period (characteristic range) 370 days Precipitation total (characteristic range) 70-110 in Frost-free period (actual range) 370 days Freeze-free period (actual range) 370 days Precipitation total (actual range) 60-140 in Frost-free period (average) 370 days Freeze-free period (average) 370 days Precipitation total (average) 90 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) PRINCEVILLE RCH 1117 [USC00518165], Princeville, HI
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(2) WAIHEE 837.5 [USC00519281], Kaneohe, HI
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(3) KAILUA 446 [USC00512679], Haiku, HI
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(4) KANEOHE MAUKA 781 [USC00513113], Kaneohe, HI
">Influencing water features
This ecological site is intersected by many small to medium size streams that have cut gulches into the landscape. The gulches contain plant species found in the ecological site (USFWS, 2023).<br />
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Number of National Wetland Inventory (NWI) features overlapping ecological site: Riverine (670), freshwater forested/shrub wetlands (271), freshwater emergent wetlands (218) freshwater ponds (92), estuarine and marine wetlands (24), estuarine and marine deepwater (15), and lakes (14) (USFWS, 2023).<br />
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Number of National Hydrologic Dataset (NHD) features overlapping ecological site: Lakes/ponds (102), reservoirs (10), streams/rivers (6), swamp/marsh (4), sea/ocean (3), and foreshore (1) (USGS, 2019).Soil features
The soil components associated with this ecological site are Hihimanu, Halii, Hanamaulu, Kalapa, Kapaa, Lawai, Makapili, Pooku, Kailua, Makawao, Pauwela, Kaneohe, Lolehaa, Paumalu, Tantalus, Waikane, and Haiku.
Most of the soils correlated with this ecological site are highly weathered Oxisols and Ultisols. Less frequent soil orders in this ecological site include Andisols and Inceptisols. All of the soils are very deep and well drained. All the soils have mineralogy that gives them pH dependent ion retention characteristics, apart from Tantalus which has pH high enough to impart significant cation retention. Most the soils have low pH in a range that can solubilize aluminum to toxic levels unless counteracted by adequate organic matter content. Soil temperature regimes are very warm (isohyperthermic) or, in very few cases, at the warmer extreme of isothermic. Soil moisture regimes are udic (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) or at the moist extreme of ustic (in which moisture is limited but present at a time when conditions are suitable for plant growth). In general, the supply of plant nutrient cations is low, and phosphorus is in forms that are relatively unavailable to plants, so that recycling of nutrients from deeper levels to the surface by plants and storage of nutrients in surface and near-surface organic matter is crucial (USDA-SCS, 1972).Table 5. Representative soil features
Parent material (1) Alluvium – igneous rock
(2) Colluvium – igneous rock
(3) Residuum – igneous rock
(4) Volcanic ash – igneous rock
Surface texture (1) Silty clay
(2) Gravelly silty clay
(3) Stony silty clay
(4) Bouldery silty clay
(5) Clay
Family particle size (1) Very-fine
(2) Fine
(3) Clayey
(4) Medial over pumiceous or cindery
(5) Hydrous
Drainage class Well drained Permeability class Very slow to slow Depth to restrictive layer 72 in Soil depth 72 in Surface fragment cover <=3" Not specified Surface fragment cover >3" Not specified Available water capacity
(0-40in)3 – 6 in Calcium carbonate equivalent
(0-40in)Not specified Electrical conductivity
(0-40in)Not specified Sodium adsorption ratio
(0-40in)0 – 5 Soil reaction (1:1 water)
(0-10in)4.3 – 5.8 Subsurface fragment volume <=3"
(0-40in)0 – 38 % Subsurface fragment volume >3"
(0-40in)2 – 10 % Table 6. Representative soil features (actual values)
Drainage class Not specified Permeability class Very slow to moderate Depth to restrictive layer 0 in Soil depth 0 in Surface fragment cover <=3" 0 % Surface fragment cover >3" 0 % Available water capacity
(0-40in)0 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)
(0-10in)4.3 – 6.7 Subsurface fragment volume <=3"
(0-40in)0 % Subsurface fragment volume >3"
(0-40in)0 % Ecological dynamics
The information in this ecological site description (ESD), including the state-and-transition model (STM), was developed using archaeological and historical data, professional experience, and scientific studies. The information is representative of a complex set of plant communities. Not all scenarios or plants are included. Key indicator plants, animals, and ecological processes are described to inform land management decisions.
States and community phases within this ecological site were differentiated by inspection of data; ordination programs were not available. They were verified by professional consensus and observation of examples in the field.
Natural Disturbances
The natural (not human-caused) disturbances most important for discussion in this ecological site are natural fires, and wind throw. Natural fires caused by lightning might occasionally occur in the drier portions of this ecological site. Wind throw of vegetation can occur during hurricanes or other high wind events (Abrahamson, 2013).
Human Disturbances
Human-related disturbances have been much more important than natural disturbances in this ecological site since the arrival of Polynesians and, later, Europeans. These reflected in the state-and-transition model diagram.
Humans arrived in the Hawaiian Islands 1,200 to 1,500 years ago. Their population gradually increased so that by 1,600 A.D. at least 80 percent of all the lands in Hawaii below about 1,500 feet (roughly 500 meters) in elevation had been extensively altered by humans (Kirch, 1982); some pollen core data suggest that up to 100 percent of lowlands may have been altered (Athens, 1997). By the time of European contact late in the 18th century, the Polynesians had developed high population densities and placed extensive areas under intensive agriculture (Cuddihy and Stone, 1990).
Prehistoric native lowland forest disturbance can be attributed to clearing for agriculture by hand or by fire, introduction of new plants and animals, and wood harvesting. Less accessible areas may have been affected by factors such as inadvertently introduced plant diseases and seed predation the introduced Pacific rat (Athens, 1997).
Approximately 62 percent (79,632 acres) of this 129,751-acre ecological site overlaps with the Lincoln et al., (2023) modeled "Agroforestry" agroecological systems; Of which, 39 percent (50,350 acres) are modeled as Marginal Agroforestry systems, and 23 percent (29,282 acres) are modeled as Intensive Agroforestry systems.
Marginal Agroforestry was a low intensity tree cropping system where the native forest canopy was retained, and shade tolerant crops were cultivated including banana or maia (Musa babisiana), water yam or uhi (Dioscorea alata), air yam or hoi (Dioscorea bulbifera), Waimea pipturus or mamaki (Pipturus albidus), and olona (Touchardia latifolia) (Lincoln et al., 2023).
Intensive Agroforestry was a managed tree cropping system which resulted in native forests becoming “replaced over time by Polynesian introduced trees, such as ‘ulu (breadfruit), kukui (candlenut), and ‘ohi‘a‘ai (mountain apple; Syzygium malaccense), along with some shade tolerant crops and native species in the understory (Handy et al., 1991; Meilleur et al., 2004; Lincoln, 2020)” (Lincoln et al., 2023, p. 06).
After the arrival of Europeans, documentary evidence attests to accelerated and extensive deforestation, erosion, siltation, and changes in local weather patterns (Kirch, 1983) due to more intensive land use, modern tools, and introduction of more plant, animal, and microbe species.
The Polynesians introduced dogs, Pacific rats, and small pigs to the islands. Cattle, sheep, horses, goats, and larger European pigs were introduced in the final decade the 18th century. These animals ranged free on the islands, becoming very numerous and destructive by the early decades of the 19th century (Henke, 1929).
Through the 20th and into the 21st centuries, increases in human populations with attendant land development, as well as accelerated introduction of non-native mammals, birds, reptiles, amphibians, invertebrates, plants, and microorganisms, have brought about dramatic changes to wild ecosystems in Hawaii. This ecological site evolved without the presence of large mammals or human-caused fires.
The most important human disturbances in this ecological site are clearing for agriculture, domestic and feral ungulate foraging, and invasion by introduced plant and animal species. Much of the area is currently used for agriculture and pasture. Some areas had been cleared in the past and then abandoned; these areas are now dominated by forests of introduced species. Large areas are in urban uses (USDA-NRCS, 2006).State and transition model
Custom diagramStandard diagram
Figure 7. State-and-transition model (STM) diagram for the Oxidic Dissected Lowland (R167XY001HI).
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
States 1 and 5 (additional transitions)
T1A - The Reference State (1) transitions to the Weed Invaded Grassland State (5) by long-term continuous grazing and lack of weed control measures. Remnant desirable forages have been grazed out and replaced entirely by weedy grasses, forbs, shrubs, and small trees. R2B - The Invaded Understory State (2) can be restored to the Reference State (1) by clearing the forest with heavy machinery and planting desirable forage species. T2A - The Invaded Understory State (2) transitions to the Invaded Overstory and Understory State (3) through the process of fast-growing weeds inhibiting reproduction of native plants and gradually replacing them. This process is accelerated by feral pigs and cattle directly damaging native plants and promoting the spread of weeds by disturbing the soil and spreading weed seeds. R2A - The Invaded Understory State (2) may be restored to a facsimile of the Native Forest State (4). Construction of a suitable fence and removal of all ungulates are necessary. Intensive weed control must then be initiated and maintained in the long term. In some cases, large amounts of dead weed biomass must be dealt with by removal or decomposition. Reintroduction of missing native species will be necessary. R3A - The Invaded Overstory and Understory State (3) can be converted to the Reference State (1) by clearing vegetation using heavy machinery, applying aggressive weed control measures, and planting desirable forage species. T4B - The Native Forest State (4) can transition to the Reference State (1) by clearing the forest with heavy machinery and planting desirable pasture species. Native forest may be cleared gradually by allowing cattle access to the forest. Cattle eventually eat or destroy understory ferns, forbs, shrubs, and saplings, opening the forest so that introduced grasses will thrive. T4A - The Native Forest State (4) transitions to the Invaded Understory State (2) by the very aggressive, introduced weed species present in this ecological site invading intact native forest and gradually replacing native species in the understory. This invasion is greatly facilitated by feral pigs and cattle that damage and consume native plants, disturb the soil, and spread weed seeds. R5A - The Weed Invaded Grassland State (5) can be restored to the Reference State (1) by brush management, re-establishment of desirable forage species, persistent weed control, and prescribed grazing. T5A - The Weed Invaded Grassland State (5) transitions to the Invaded Overstory and Understory State (3) due to the presence of fast-growing, introduced tree species; fire may prevent this from occurring. State 1 submodel, plant communities
1.1A - Phase 1.1 changes to phase 1.2 by long-term continuous grazing. Remnant high-quality forages have been greatly reduced in abundance and largely replaced by lower-value species. Weedy forbs and shrubs are increasing. 1.2A - A grazing plan is needed that provides for intensive but temporary grazing of pastures to ensure that cattle consume some low-value forage species along with preferred forages and to allow preferred forages time to recover from defoliation. Desirable grass species are competitive and able to recover with proper management. The grazing plan may require splitting the herd, creating additional water sources, and creating multiple pastures by cross-fencing. Weed control may be necessary to eliminate some species such as inedible shrubs. State 2 submodel, plant communities
State 3 submodel, plant communities
State 4 submodel, plant communities
State 5 submodel, plant communities
State 1
Reference StateThe Reference State (1) consists of two community phases dominated by introduced grass species. This state is considered to be the Reference State because no intact examples of native forest remain, and species compositions of the forests consisting of introduced species are variable.
Continuous grazing results in increased abundance of less desirable forage species, as represented by the phase change from 1.1 Guineagrass/Ticktrefoil (Desmodium) to 1.2 Hilograss – Common Carpetgrass/Spiny Amaranth. Longer-term overgrazing and lack of weed control measures results in a transition to the Weed-Invaded Grassland State (5).Community 1.1
Guineagrass/Ticktrefoil (Desmodium)Dominance of desired forage species is maintained by prescribed grazing techniques that allow desired species time to recover from grazing and trampling but includes periods of grazing of sufficient intensity to suppress invasion of weedy shrubs and trees. Failure to properly maintain the selected forage species results in this community phase shifting to community phase 1.2.
There typically is no overstory in this community other than sparse shade trees. The common forage species is guineagrass (Urochloa maxima) in mixture with leguminous ticktrefoil species (Desmodium spp.). Para grass or Californiagrass (Urochloa mutica) is common in wetter parts of the ecological site. White leadtree or koa haole (Leucaena leucocephala) is a useful leguminous browse species in drier areas (Wagner et al., 1999).Dominant plant species
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guineagrass (Urochloa maxima), grass
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ticktrefoil (Desmodium), other herbaceous
Community 1.2
Hilograss – Common Carpetgrass/Spiny AmaranthThere typically is no overstory in this community other than sparse shade trees. This community phase is dominated by grasses of lower forage value. Desirable forage legumes largely have been grazed out, and weedy forbs and shrubs have increased. It can be shifted back to phase 1.1 by using a prescribed grazing plan.
Common carpetgrass (Axonopus fissifolius), hilograss (Paspalum conjugatum), and rat-tail grass (Sporobolus indicus var. capensis) are typically the most abundant grasses. Weedy forbs such as shameplant or sensitive plant (Mimosa pudica) and spiny amaranth (Amaranthus spinosus) also are common. Ticktrefoil or Desmodium species have decreased in abundance (Wagner et al., 1999).Dominant plant species
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hilograss (Paspalum conjugatum), grass
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common carpetgrass (Axonopus fissifolius), grass
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spiny amaranth (Amaranthus spinosus), other herbaceous
Pathway 1.1A
Community 1.1 to 1.2Phase 1.1 changes to phase 1.2 by long-term continuous grazing. Remnant high-quality forages have been greatly reduced in abundance and largely replaced by lower-value species. Weedy forbs and shrubs are increasing.
Pathway 1.2A
Community 1.2 to 1.1A grazing plan is needed that provides for intensive but temporary grazing of pastures to ensure that cattle consume some low-value forage species along with preferred forages and to allow preferred forages time to recover from defoliation. Desirable grass species are competitive and able to recover with proper management. The grazing plan may require splitting the herd, creating additional water sources, and creating multiple pastures by cross-fencing. Weed control may be necessary to eliminate some species such as inedible shrubs.
State 2
Invaded Understory StateThe Invaded Understory State (2) consists of one community phase. Native ‘ohi’a lehua and Tahitian screwpine or hala trees may be present in some locations. However, introduced trees, shrubs, vines, and ferns produce a dense layer of low, competitive vegetation that severely inhibits reproduction of native species. Activity of feral pigs and cattle further reduces native plant abundance and produces bare, disturbed soil patches that promote weed invasion. Eventually, the Invaded Understory State (2) transitions to the Invaded Overstory and Understory State (3) through growth of introduced tree species.
Community 2.1
'Ohi'a Lehua/Kahila Garland-Lily (Kahili Ginger)/Asian SwordfernWhile native trees may be present, introduced tree species have invaded the overstory. Smaller, shade-tolerant introduced trees and shrubs gradually produce extremely dense canopies and root systems that exclude other species. Dense stands of introduced ferns form a layer that inhibits reproduction of native species.
‘Ohi’a lehua (Metrosideros polymorpha) and Tahitian screwpine or hala (Pandanus tectorius) may be present. Introduced tree species with the potential to grow tall, such as African tuliptree (Spathodea campanulata), small Philippine acacia or Formosan koa (Acacia confusa), Indian walnut or kukui (Aleurites moluccanus), beach sheoak or ironwood (Casuarina equisetifolia), silkoak (Grevillea robusta), peacocksplume or albizia (Falcataria moluccana), and Java plum (Syzygium javanicum) are abundant (Wagner et al., 1999).
Strawberry guava (Psidium cattleianum), guava (Psidium guajava), and Java plum (Syzygium javanicum) are increasingly abundant, gradually forming extremely dense stands. The introduced ferns Asian swordfern (Nephrolepis multiflora syn. N. brownii), musk fern or maile-scented fern (Phymatosorus grossus), and downy maiden fern (Thelypteris dentata) form dense stands under 3 feet (about 1 meter) tall. Native Old World forkedfern or uluhe fern (Dicranopteris linearis) occurs in some locations. Soapbush or Koster’s curse (Clidemia hirta) and Kahila garland-lily or kahili ginger (Hedychium gardnerianum) are present and increasing in abundance.Dominant plant species
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'ohi'a lehua (Metrosideros polymorpha), tree
-
Kahila garland-lily (Hedychium gardnerianum), shrub
-
Asian swordfern (Nephrolepis multiflora), other herbaceous
State 3
Invaded Overstory and Understory StateThe Invaded Overstory and Understory State (3) consists of one community phase dominated by introduced species in both the overstory and understory. Some individual native trees may persist for their lifetime. The diversity of weedy trees, shrubs, vines, ferns, and herbs is high, and the species mix is variable. Conversion to Reference State (1) is possible by using heavy machinery and applying aggressive weed control and ungulate-exclusion measures.
Community 3.1
Java plum – Strawberry Guava/Kahila Garland-Lily (Kahili Ginger)/Asian Swordfern‘Ohi’a lehua (Metrosideros polymorpha) and Tahitian screwpine or hala (Pandanus tectorius) trees persist until they die, but do not successfully reproduce. The introduced species present on different sites varies (Wagner et al., 1999).
Forest overstory.Monotypic or mixed stands of strawberry guava (Psidium cattleianum), African tulip tree (Spathodea campanulata), small Philippine acacia or Formosan koa (Acacia confusa), Indian walnut or kukui (Aleurites moluccanus), beach sheoak or ironwood (Casuarina equisetifolia), silkoak (Grevillea robusta), and Java plum (Syzygium javanicum) may develop. Fast-growing peacocksplume or albizia (Falcataria moluccana) may eventually overtop all other species (Wagner et al., 1999).
Forest understory. The understory varies among locations. Dense overstories of strawberry guava, silkoak, or ironwood may allow only a sparse understory to grow. Otherwise, soapbush or Koster’s curse (Clidemia hirta), lantana (Lantana camara), guava (Psidium guajava), and Kahila garland-lily or kahili ginger (Hedychium gardnerianum) may be abundant. Introduced ferns (see Community 2.1) are typically present, and grass species such as molassesgrass (Melinis minutiflora) and guineagrass (Urochloa maxima) grow abundantly where enough light penetrates the overstory. Centipede tongavine or pothos vine (Epipremnum pinnatum) often grows into the overstory (Wagner et al., 1999).
Dominant plant species
-
Java plum (Syzygium javanicum), tree
-
strawberry guava (Psidium cattleianum), tree
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Kahila garland-lily (Hedychium gardnerianum), shrub
-
Asian swordfern (Nephrolepis multiflora), other herbaceous
State 4
Native Forest StateThe Native Forest State (4) consists of one community phase. Because no examples of this state remain, the following description is historical, based on literature and historical accounts of the islands before human influences disturbed these native plant communities.
When cleared by machinery or long-term, heavy ungulate browsing, this state transitions to the Reference State (1). Gradual invasion by weedy, introduced plant species brings a transition to the Invaded Understory State (2).Community 4.1
'Ohi'a Lehua – Tahitian Screw Pine (Hala)/Oahu False OheloThis historical community phase is a forest with a medium to tall stature (50 to 75 feet or 15 to 23 meters) with closed to open overstory, a secondary canopy of diverse trees species, an open tree fern canopy in moister locations, and a diverse understory of shrubs, vines, and ferns. Species composition varies to an extent along climatic moisture gradients within the ecological site.
The dominant overstory species would have been ‘ohi’a lehua (Metrosideros polymorpha). It is possible that koa (Acacia koa) was present in the overstory, particularly at higher elevations (Wagner et al., 1999).
The secondary tree canopy likely would have included Tahitian screwpine or hala (Pandanus tectorius), kolea lau nui (Myrsine lessertiana), aulu (Pisonia sandwicensis), variable starviolet or manono (Hedyotis terminalis), umbrella catchbirdtree or papala (Pisonia umbellifera), ho’awa (Pittosporum confertiflorum), Waimea pipturus or mamaki (Pipturus albidus), kopiko ‘ula (Psychotria hawaiiensis), kopiko kea (P. kaduana), forest wild coffee (P. mariniana), and ‘opiko (P. mauiensis). In drier extremes of the ecological site, Hawai’i olive or olopua (Nestegis sandwicensis), lama (Diospyros sandwicensis), hame (Antidesma pulvinatum), and cream cheesewood or hoawa (Pittosporum terminalioides), and Oahu false ohelo (Wikstroemia oahuensis) may have been present.
Tree ferns, or hapu’u (Cibotium glaucum) and hapu’u li (Cibotium menziesii) would have been present in the wetter parts of the ecological site, as would shrubs of the genera Cyanea, Clermontia, and Labordia. Likely vine species are queen coralbead or huehue (Cocculus orbiculatus) and hawai’i greenbrier or hoi kuahiwi (Smilax melastomifolia). Old World forkedfern or Uluhe fern (Dicranopteris linearis) would have been common, along with many small fern species.Dominant plant species
-
'ohi'a lehua (Metrosideros polymorpha), tree
-
Tahitian screwpine (Pandanus tectorius), tree
-
Oahu false ohelo (Wikstroemia oahuensis), shrub
State 5
Weed Invaded Grassland StateThe Weed Invaded Grassland State (5) consists of one community phase consisting primarily of weedy shrubs and small trees. Weedy grasses and forbs dominate between shrub patches. Introduced tree species are present and will attain dominance if fire does not set them back.
Community 5.1
Guava – Brazilian Peppertree (Christmasberry)/Asian Swordfern/Molassesgrass – Common CarpetgrassThis community phase has a wide diversity of mostly introduced species. Tall overstory is typically sparse to absent. Strawberry guava (Psidium cattleianum), guava (Psidium guajava), Brazilian peppertree or christmasberry (Schinus terebinthifolius), Java plum (Syzygium javanicum), cure for all or sourbush (Pluchea carolinensis), and soapbush or Koster’s curse are common and poised to expand rapidly. Asian swordfern (Nephrolepis multiflora) is abundant. Forage legumes such as ticktrefoil or desmodium (Desmodium spp.) and white leadtree or koa haole (Leucaena leucocephala) are rare or absent. High quality forage grasses are sparse, while low quality species such as rat-tail grass (Sporobolus indicus var. capensis), molassesgrass (Melinis minutiflora), Hilograss (Paspalum conjugatum), and common carpetgrass (Axonopus fissifolius) are abundant (Wagner et al., 1999).
Dominant plant species
-
guava (Psidium guajava), tree
-
Brazilian peppertree (Schinus terebinthifolius), tree
-
molassesgrass (Melinis minutiflora), grass
-
common carpetgrass (Axonopus fissifolius), grass
-
Asian swordfern (Nephrolepis multiflora), other herbaceous
Transition T1A
State 1 to 5The Reference State (1) transitions to the Weed Invaded Grassland State (5) by long-term continuous grazing and lack of weed control measures. Remnant desirable forages have been grazed out and replaced entirely by weedy grasses, forbs, shrubs, and small trees.
Restoration pathway R2B
State 2 to 1The Invaded Understory State (2) can be restored to the Reference State (1) by clearing the forest with heavy machinery and planting desirable forage species.
Transition T2A
State 2 to 3The Invaded Understory State (2) transitions to the Invaded Overstory and Understory State (3) through the process of fast-growing weeds inhibiting reproduction of native plants and gradually replacing them. This process is accelerated by feral pigs and cattle directly damaging native plants and promoting the spread of weeds by disturbing the soil and spreading weed seeds.
Restoration pathway R2A
State 2 to 4The Invaded Understory State (2) may be restored to a facsimile of the Native Forest State (4). Construction of a suitable fence and removal of all ungulates are necessary. Intensive weed control must then be initiated and maintained in the long term. In some cases, large amounts of dead weed biomass must be dealt with by removal or decomposition. Reintroduction of missing native species will be necessary.
Restoration pathway R3A
State 3 to 1The Invaded Overstory and Understory State (3) can be converted to the Reference State (1) by clearing vegetation using heavy machinery, applying aggressive weed control measures, and planting desirable forage species.
Transition T4B
State 4 to 1The Native Forest State (4) can transition to the Reference State (1) by clearing the forest with heavy machinery and planting desirable pasture species. Native forest may be cleared gradually by allowing cattle access to the forest. Cattle eventually eat or destroy understory ferns, forbs, shrubs, and saplings, opening the forest so that introduced grasses will thrive.
Transition T4A
State 4 to 2The Native Forest State (4) transitions to the Invaded Understory State (2) by the very aggressive, introduced weed species present in this ecological site invading intact native forest and gradually replacing native species in the understory. This invasion is greatly facilitated by feral pigs and cattle that damage and consume native plants, disturb the soil, and spread weed seeds.
Restoration pathway R5A
State 5 to 1The Weed Invaded Grassland State (5) can be restored to the Reference State (1) by brush management, re-establishment of desirable forage species, persistent weed control, and prescribed grazing.
Transition T5A
State 5 to 3The Weed Invaded Grassland State (5) transitions to the Invaded Overstory and Understory State (3) due to the presence of fast-growing, introduced tree species; fire may prevent this from occurring.
Additional community tables
Table 7. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 8. Community 1.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 9. Community 2.1 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 (%) Table 12. Community 5.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Supporting information
Other references
REFERENCES for R167XY001HI Oxidic Dissected Lowland
Abrahamson, I.L. (2013). Fire regimes in Hawai’ian plant communities. Fire Effects
Information System [https://www.fs.usda.gov/database/feis/fire_regimes/Hawaii/all.html].
Athens, J.S. (1997). Prehistoric environmental and landscape change. In Kirch, P.V. & T.L. Hunt (Eds.), Hawai’ian native lowland vegetation in the Pacific Islands (Pgs. 248 -270). Yale University Press. [https://www.pelagicos.net/BIOL3010/readings/Athens_1997.pdf].
Cuddihy, L.W., & C.P. Stone. (1990). Alteration of native Hawai’ian vegetation: Effects of humans, their activities and introductions. University of Hawaii Cooperative National Park Resources Study Unit.
Department of Land and Natural Resources (2024). Hawai’i State Aha Moku. [https://dlnr.hawaii.gov/ahamoku/councils/].
Giambelluca, T.W., Q. Chen, A.G. Frazier, J.P. Price, Y.L. Chen, P.-S. Chu, J.K. Eischeid, & D.M. Delparte. (2013): Online rainfall atlas of Hawai’i. Bull. Amer. Meteor. Soc. 94, 313-316, DOI: [https://doi.org/10.1175/BAMS-D-11-00228.1].
Giambelluca, T.W., X. Shuai, M.L. Barnes, R.J. Alliss, R.J. Longman, T. Miura, Q. Chen, A.G. Frazier, R.G. Mudd, L. Cuo, & A.D. Businger. (2014). Evapotranspiration of Hawai’i. Final report submitted to the U.S. Army Corps of Engineers - Honolulu District, and the Commission on Water Resource Management, State of Hawai’i. [https://www.hawaii.edu/climate-data-portal/evapotranspiration-atlas/].
Handy, E.S.C., E.G. Handy, & Pukui, M.K. (First Edition 1972, Revised Edition 1991). Native planters in old Hawai’i: Their life, lore, and environment. Bishop Museum Press.
Henke, L.A. (1929). A survey of livestock in Hawai’i. Research Publication No. 5. University of Hawai’i, Honolulu. [https://www.ctahr.hawaii.edu/oc/freepubs/pdf/RP-5.pdf].
Juvik, J.O., & Nullett, D. (1993). A climate transect through tropical montane rain forests in Hawai’i. Department of Geography, University of Hawai’i at Hilo, Hilo Hawai’i. Journal of Applied Meteorology. Volume 33.
Kirch, P.V. (1982). The impact of the prehistoric Polynesians in the Hawai’ian ecosystem. Pacific Science 36 (1):1-14.
Kirch, P.V. (1983). Introduction. In Archaeological investigations of the Mudlane-Waimea-Kawaihae Road Corridor, Island of Hawai’i: An Interdisciplinary Study of an Environmental Transect. Clark, J.T. and Kirch, P.V., eds. Dept. of Anthropology, Bernice Pauahi Bishop Museum, Report 83-1, Honolulu, HI.
Leopold, L.B. (1949). The interaction of trade wind and sea breeze, Hawai’i. Journal of Meteorology 6: 312-320.
Lincoln, N. K. (2020). Agroforestry form and ecological adaptation in ancient
Hawai’i: extent of the pakukui swidden system of Hamakua, Hawai’i Island. Agric. Syst.
181, 102808. doi: [https://doi.org/10.1016/j.agsy.2020.102808].
Lincoln, N.K, T.P. Haensel, & Lee, T.M. (2023). Modeling Hawai’ian agroecology: Depicting traditional adaptation to the world’s most diverse environment. Frontiers in Sustainable Food Systems. Climate-Smart Food Systems. Volume 7 – 2023. Pg. 06.
[https://doi.org/10.3389/fsufs.2023.1116929].
Malo, D. (1903). Hawaiian antiquities. N.B. Emerson (trans.). Bishop Museum Special Publication 2. Honolulu.
Meilleur, B. A., Jones, R. R., Titchenal, C. A., and Huang, A. S. (2004). Hawaiian Breadfruit: Ethnobotany, Nutrition, and Human Ecology. Honolulu, HI: College of Tropical Agriculture and Human Resources, University of Hawai’i.
Sanderson, M. (ed.). (1993). Prevailing trade winds, weather and climate in Hawai’i. University of Hawai’i Press. Honolulu.
U.S. Department of Agriculture, Natural Resources Conservation Service. (2006). Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. United States Department of Agriculture, Agriculture Handbook 296. [https://www.nrcs.usda.gov/sites/default/files/2022-10/AgHandbook296_text_low-res.pdf].
U.S. Department of Agriculture, Soil Survey Conservation Service. (1972). Soil survey of Islands of Kauai, Oahu, Maui, Molokai, and Lanai, State of Hawai’i. Foote D.E., Hill E.L., Nakamura S., & F. Stephens, in cooperation with The University of Hawai’i Agricultural Experiment Station.
U. S. Department of Interior, Fish & Wildlife Service. (2023). Download seamless wetlands data by state. National Wetlands Inventory website. U.S. Department of the Interior, Fish and Wildlife Service, Washington, D.C. Accessed April 24, 2024.
[https://www.fws.gov/program/national-wetlands-inventory/download-state-wetlands-data].
U.S. Department of Interior, Geological Survey. (2006). A Gap analysis of Hawai’i: February 2006 final report. National gap analysis program. [https://catalog.lib.uchicago.edu/vufind/Record/6329681/Details].
U.S. Department of Interior, Geological Survey. (2019). National Hydrography Dataset (NHD) – USGS national map downloadable data collection: USGS – National Geospatial Technical Operations Center (NGTOC). [https://www.usgs.gov/national-hydrography/access-national-hydrography-products].
Wagner, W.L., D.R. Herbst, & S.H. Sohmer. (1999). Manual of the flowering plants of Hawai’i, Revised Edition. Bishop Museum Press, Honolulu.
Western Regional Climate Center, (2020). Climate of Hawai’i. Available: [https://wrcc.dri.edu/Climate/narrative_hi.php].
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.
Available water capacity: The amount of soil water available to plants to the depth of the first root-restricting layer.
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.
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.
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.
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.
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.
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.
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.
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 1,500 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.
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.
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.Contributors
David Clausnitzer PhD
John Proctor
Carolyn Auweloa
Kendra Moseley
Amy Koch
Ann Tan
Daniel Bowman
Jennifer Fedenko
Sarah QuistbergApproval
Kendra Moseley, 5/08/2025
Acknowledgments
Assistance, advice, review, and/or insights: 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 Mike Kolman, NRCS Jennifer Higashino, NRCS 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
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 10/02/2026 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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