State 1
Reference State

The Reference State consists of one plant community. Under a regime of natural disturbances, this community has probably been stable through post-glacial time frames and from a broad-scale spatial perspective. A matrix of variations in canopy cover and species composition in all canopy levels is observable. This matrix variability does not appear to be connected to soils, climate, or landscape features, but rather is probably due to wind throw, deaths of large trees, and other chance occurrences.

State 1 will transition into State 2, Grassland State, by either active clearing by humans or by heavy foraging over time by feral ungulates. It can transition into State 4, Invaded Understory State, by gradual weed invasion, which is exacerbated by feral ungulates.

Community 1.1
Koa - `ohi`a lehua/hapu`u/small ferns

Figure 8. Reference Community Phase 12/06/08 D Clausnitzer MU956

Figure 9. Aerial view with recent lava flow 9/15/08 D Clausnitzer

Figure 10. View of the two upper strata 3/27/07 D Clausnitzer MU851

Figure 11. Within the tree fern stratum D Clausnitzer generic photo

Figure 12. The lowest stratum 3/27/07 D Clausnitzer MU851

Figure 13. The forest floor 1/5/10 D Clausnitzer generic photo

Figure 14. Forest floor close-up 9/14/09 D Clausnitzer generic photo

Figure 15. Heavy koa phyllode litter, Humuula Trail 9/14/09 D Clausnitzer generic photo

Figure 16. Downed tree 3/27/07 D Clausnitzer MU851

Figure 17. Young lava flow vegetation D Clausnitzer generic photo

This community phase is a forest consisting of four canopy strata: an open or closed upper canopy of ohia lehua or ohia lehua and koa up to 100 feet (30 meters) tall, a secondary canopy of diverse tree species 30 to 60 feet (9 to 18 meters) tall, a dense tree fern canopy 10 to 30 feet (3 to 9 meters) tall, and a diverse understory of shrubs and ferns. Vines are common both on the ground and on trees. All three Big Island tree fern species are present. These forests have standing live timber of 800 to 5700 cubic feet per acre, with a representative value of about 3000 cubic feet per acre. Typical low values are about 1500 cubic feet per acre.

Canopy cover of ohia lehua and koa in the upper canopy varies on the microscale from about 10% to 80%, with a representative value of 40 to 50% on a macroscale. Secondary canopy cover of medium-stature tree species is typically about 20%, concentrated in the 30 to 40 feet (9 to 12 meters) height range. Cover of the tertiary tree fern canopy is usually in the range of 60% to 90%, mostly between 13 to 25 feet (4 to 8 meters) tall.

Koa and ohia lehua do not reproduce successfully in the shady understory of intact forest. Tree ferns, medium-stature tree species, and shrubs reproduce and grow well in the understory. The ground layer of small ferns is typically dense and diverse in the absence of introduced ungulates.

A heavy litter layer that appears to inhibit establishment of small plants is usually present on the soil surface. In particular, dead tree fern fronds produce a coarse, thick, heavy litter layer. Koa phyllodes create a firm, continuous litter layer. Phyllodes are petioles (leaf stalks) that are adapted to function as leaves on mature koa trees.

At forest edges near recent lava flows or in small kipukas, the plant communities have been seared by heat and, in some cases, burned by wildfires ignited by hot lava. Species richness and plant statures vary considerably in these locations. It is even possible to find two clear variations of the Reference Community present within one small kipuka. In general, these areas contain ohia lehua without koa, a sparse understory of kopiko, hapuu, small native ferns, and a scattering of other tree, shrub, and vine species. Plant statures across the board are smaller than those found in mature forest. Soils fall within the range of the soil series concept but may differ somewhat from the type location description.

Forest overstory.The uppermost forest canopy consists of ohia lehua or a combination of ohia lehua and koa. There seems to be no consistent relationship between dominant tree canopy composition and soil type, rainfall, elevation, or any other environmental variable. Neither overstory species grows well in shade. Primary succession in Hawaii typically results in an initial forest overstory of ohia lehua, often consisting of roughly even-aged cohorts. It is likely that long-term disturbance history controls koa occurrence. Koa is a fast growing, opportunistic species that is able to take advantage of temporary openings in the forest canopy. Wind fall, nearby lava flows, or death of ohia lehua population cohorts would provide the conditions for koa expansion where their seeds are present. Koa also can reproduce by sprouting from near-surface roots.

Forest understory. The secondary canopy contains about 15 tree species, the most common of which are kopiko or wild coffee (Psychotria spp.), hame (Antidesma spp.), olapa or olapalapa (Cheirodendron trigynum), kolea lau nui (Myrsine lessertiana), and pilo or woodland mirrorplant (Coprosma rhynchocarpa). The palm native to this ecological site, loulu or louulu (Pritchardia lanigera), is rare but may have been more abundant in the past.<br /> <br /> The tertiary canopy is dominated by three species of hapuu or tree ferns: hapuu (Cibotium glaucum), hapuu ii or hapuu li (Cibotium menziesii), and hapuu or Chamisso’s manfern (Cibotium chamissoi). Cibotium glaucum is the most abundant, followed by C. menziesii; C. chamissoi is the least abundant. This canopy contains about 25 species of small trees.<br /> <br /> The lowest canopy stratum, which ranges in height from the ground to about 4.5 feet (1.5 meters), consists of seedlings and immature individuals of species in the taller strata, about 8 small shrub species, about 11 forb species, about 5 vines (some prostrate, some climbing, some both), 3 common sedges, and over 30 species of ferns and fern allies.

State 2
Naturalized Grassland State

The elevation range of the forest found in the Reference State does not coincide perfectly with the elevation range of the dominant grass species within the Grassland State. In some areas at the higher elevation range of this ecological site, kikuyugrass (Pennisetum clandestinum) replaces guineagrass as the dominant species. More detailed information, including forage production estimates, about these kikuyugrass grasslands can be found in Ecological Site Description F160XY502 Isomesic-Cool Isothermic Forest.

This state consists of three grassland community phases. These phases are maintained by grazing, which keeps preferred species from becoming too tall, and adequate recovery periods, which ensure vigor and cover of preferred species. High production of preferred grass species and extensive cover allow for increased soil moisture retention, vegetative production, and overall soil quality. These factors are degraded by grazing practices that result in loss of preferred grass species leading to increase in less desirable grasses, weed invasion, and an increase in the extent of bare soil.

Prescribed burning generally is not allowed due to high risks to structures, fences, and native forest stands. Wildfires caused by lightning or arson sometimes occur. They are very intense and difficult to contain, because guineagrass produces huge amounts of fuel and grows to a height of almost 10 feet (3 meters), while kikuyugrass produces large amounts of fuel and has rhizomes that can smolder underground for days, sometimes reigniting a surface fire.

Most of the grasslands in this ecological site are on former sugar plantations where guineagrass (Urochloa maxima) was a species of roadsides and waste areas (Earl Spence, rancher and manager, personal communication). Guinea grass now has taken over these lands as the dominant forage grass. All grass, sedge, forb, vine, shrub, and tree species found in this state have been introduced to Hawaii by humans within the past two centuries, either inadvertently or intentionally. Scattered, remnant native trees, either koa or ohia lehua, sometimes occur in these naturalized grasslands, but they are unable to reproduce without protection from ungulates and control of grasses and weeds. Occasionally, western brackenfern (Pteridium aquilinum) and uluhe or Old World forkedfern (Dicranopteris linearis) occur; both of these fern species are native to Hawaii.

Community Phase 2.1 mostly consists of guineagrass, sometimes with an admixture of glycine or perennial soybean (Neonotonia wightii). Continuous grazing that does not allow the preferred forage species to recover from defoliation results in Community Phase 2.2, which is dominated by lower value grass species but contains enough remnant guineagrass to allow for a shift back to Plant Community 1 with prescribed grazing. Longer-term continuous grazing leads to Community Phase 2.3, which consists of low value grass species and increasing cover of alien shrubs and tree saplings. Improvement of this Plant Community requires weed control followed by prescribed grazing.

Community 2.1
Guineagrass - kikuyugrass/glycine

Figure 18. Good condition guineagrass D Clausnitzer generic photo

Figure 19. Well-managed hilograss pasture Chinchuk Road 5/28/08 D Clausnitzer generic photo

Figure 20. Signalgrass pasture Chinchuk Road 5/28/08 D Clausnitzer generic photo

The dominant grass species in this pasture type is guineagrass that has volunteered or been seeded on old sugarcane plantations. In some higher elevation areas, kikuyugrass was planted and became naturalized. Kikuyugrass spreads mostly by rhizomes and stolons. For further information about kikuyugrass production and management, please refer to Ecological Site Description F160XY502 Isomesic-Cool Isothermic Forest.

Guinea grass is very productive and nutritious for livestock. Careful management of this caespitose (bunch-forming) grass is required to maintain it at an efficient height (two to four feet) while maintaining sufficient ground coverage by leaves, litter, and grass clumps to protect the soil from erosion and to suppress weed growth.

Forest understory. Guinea grass is very competitive with other plants when properly managed and can comprise 85 to nearly 100% of the total production on a site. Forbs, shrubs, tree seedlings, and other grass species can occur in the interspaces between guineagrass bunches but are insignificant in their share of total production in well-managed sites. They are kept in check by competition with guinea grass and foraging and trampling by livestock. Perennial soybean or glycine (Neonotonia wightii), a competitive (and potentially weedy in forests), climbing legume vine, and three-flowered ticktrefoil (Desmodium triflorum), a prostrate legume, are desirable forage species that can be maintained within guinea grass stands by careful grazing management.

Community 2.2
Hilograss - carpetgrass

Figure 22. Overgrazed guineagrass with shorter species D Clausnitzer generic photo

Figure 23. Invaded by Andropogon virginicus, Kaiwiki soil D Clausnitzer generic photo

This community phase is dominated by grass and grasslike species with lower forage value than guineagrass. Cattle can be maintained on these forages, but animal growth and vigor will be reduced. Also, the number of weedy species is high, and their stature, seed production potential, and wide distribution can lead to rapid increase and a shift to Community Phase 2.3 unless management is improved.

Forest understory. The most abundant grasses are hilograss (Paspalum conjugatum), common carpetgrass (Axonopus fissifolius), and shortleaf spikesedge (Kyllinga brevifolia), all of which have lower stature and are much less productive than guineagrass. Significant amounts (around 20% canopy cover) of guineagrass remain, but it is grazed low and is scattered across the site. Desirable forage legumes have been grazed out. Height of weedy trees, shrubs, ferns, vines, and forbs is low, and the combined cover of all these species is about 5 to 20%.

Community 2.3
Common guava - christmasberry/sourbush/broomsedge - beardgrass

Figure 24. Overgrazed grassland with common guava D Clausnitzer generic photo

This community phase is dominated by grass species with little or no forage value. Guineagrass typically comprises a small portion (roughly 5% canopy cover) of the grasses present, but sometimes is more abundant but of low stature. Spiny forbs and vines are common, as are a large number of forb and fern species with little or no forage value. Introduced shrubs and small trees are common, and seedlings and saplings of large, introduced tree species are present. Bare soil is 10% or more of the ground surface. The abundance of immature naturalized trees with potential mature heights of 20 to over 100 feet (6 to over 30 meters) presents a strong risk of losing the grassland to weedy forest.

Improving the grazing regime is extremely unlikely to shift this phase to a more productive grassland phase due to the abundance of weeds. Frequent mowing is not worthwhile; it will keep shrubs and trees in check but will do little to improve the grass and forb community. Herbicide treatments are needed to reduce weed abundance. Reseeding of guineagrass may be needed, along with removal of livestock until guineagrass has reassumed dominance.

Forest understory. Hilograss, common carpetgrass, broomsedge bluestem (Andropogon virginicum), and beardgrass or Colombian bluestem (Schizachyrium condensatum) are the most abundant grasses. Sawtooth blackberry (Rubus argutus) and West Indian raspberry or thimbleberry (Rubus rosifolius) form small thickets. Shrubs such as sourbush or cure for all (Pluchea carolinensis) and lantana (Lantana camara), along with small trees such as common guava (Psidium guajava), christmasberry or Brazilian peppertree (Schinus terebinthifolius), and fayatree or firetree (Morella faya) have combined canopy cover of about 20% and heights of 2 to 4.5 feet (0.5 to 1.5 meters). Seedlings and saplings of large tree species such as octopus tree (Schefflera actinophylla) and albizia or peacocksplume (Falcataria moluccana) are often present.

Pathway 2.1A
Community 2.1 to 2.2

Guineagrass - kikuyugrass/glycine

Hilograss - carpetgrass

Plant Community 2.1 degrades to Plant Community 2.2 by continuous grazing that weakens preferred grass species and legumes in relation to less-preferred forage species such as Hilograss, narrowleaf carpetgrass, and sedges.

Pathway 2.2A
Community 2.2 to 2.1

Hilograss - carpetgrass

Guineagrass - kikuyugrass/glycine

Plant Community 2.2 can be upgraded to Plant Community 2.1 by prescribed grazing. A prescribed grazing plan provides for intensive but temporary grazing of pastures that ensures that cattle consume some low-value forage species along with preferred forages and allows preferred forages time to recover from defoliation. The grazing plan may require splitting the herd, creating additional water sources, and creating multiple pastures by cross-fencing. Invading broomsedge and beardgrass may be controlled by mowing their seed stalks before seed set and by liming to increase soil pH. Re-establishment of legume species may be needed if they have been eliminated.

Pathway 2.2B
Community 2.2 to 2.3

Hilograss - carpetgrass

Common guava - christmasberry/sourbush/broomsedge - beardgrass

Plant Community 2.2 degrades to Plant Community 2.3 by long-term continuous grazing. Guineagrass cover is greatly reduced and largely replaced by low-value forage grasses. Weedy forbs such as spiny amaranth, introduced blackberries, and introduced shrubs such as sourbush increase in the low-stature grasses that come to dominate the interspaces between guineagrass clumps. Broomsedge and beardgrass can become the most abundant grass species.

Pathway 2.3A
Community 2.3 to 2.1

Common guava - christmasberry/sourbush/broomsedge - beardgrass

Guineagrass - kikuyugrass/glycine

Plant Community 2.3 can be upgraded to Plant Community 2.1 by a combination of weed control and prescribed grazing. Weeds such as alien blackberries, sourbush, and spiny amaranth are not controllable by domestic livestock and must be killed with herbicide. The grazing prescription will require removal of livestock from the pasture until desirable grass species have reestablished adequately to support grazing. Thereafter, the grazing plan may require splitting the herd, creating additional water sources, and creating multiple pastures by cross-fencing.

Pathway 2.3B
Community 2.3 to 2.2

Common guava - christmasberry/sourbush/broomsedge - beardgrass

Hilograss - carpetgrass

Plant Community 2.3 can be upgraded to Plant Community 2.2 by controlling weedy forbs and shrubs with mowing and herbicides. Undesirable broomsedge and beardgrass can be reduced by mowing before seedset and by increasing soil pH by liming. Without a prescribed grazing plan, further improvement to Plant Community 2.1 should not be expected.

State 3
Planted Timber State

This state consists of one community phase, which is a plantation of introduced timber tree species that have been established on former sugarcane or grazing lands. With typical management, it is not susceptible to unplanned transitions or restorations to other states. However, if native koa are planted and managed properly, future restoration in the direction of the Reference State would be facilitated. There also is the possibility that some introduced timber species may provide a favorable environment for eventual restoration of native species.

Community 3.1
Exotic timber trees/guineagrass

Figure 25. Eucalyptus with guineagrass understory, Hamakua mauka D Clausnitzer generic photo

Figure 26. Eucalyptus with strawberry guava understory, Paauilo mauka 12/28/06 D Clausnitzer generic photo

Figure 27. Heavy eucalyptus litter, Hamakua mauka 3/29/10 D Clausnitzer generic photo

This community is typically managed in the long term for economic returns. Many introduced timber species grow extremely well in the environment of this ecological site, where they also may be free of pests that are present in their native habitats.

Forest overstory.Various species of Eucalyptus are most commonly planted, including the hybrid E. grandis x urophylla, grand eucalyptus (E. grandis), rainbow gum (E. deglupta), red gum (E. robusta), and blue gum (E. saligna). Other valuable species can be planted, including African mahogany (Khaya senegalensis), Honduran mahogany (Swietenia macrophylla), tropical ash or shamel ash (Fraxinus uhdei), toon or Australian red cedar (Toona ciliata), and Spanish cedar (Cedrela odorata). Other species are also possible. Consult with NRCS, the University of Hawaii Extension Forester, or a private consultant to ensure that noninvasive species are selected and that species are planted in suitable elevation ranges. Few introduced timber species are suitable for the full elevation range of this ecological site.<br /> <br /> Koa is a valuable, fast-growing native tree that can be planted on these sites. It is much more likely to thrive at elevations higher than about 1500 feet (460 meters); lower elevation plantings are often subject to diseases. Feral and domestic animals must be fenced out of koa plantations for enough years to allow the trees to attain a stature at which animals are unable to push down and eat them. Trampling of koa’s shallow roots and eating the trees’ bark can remain a problem for a longer time. There are examples of adequately mature koa stands being maintained along with careful cattle grazing in silvopastures.

Forest understory. Guineagrass is usually abundant beneath the timber trees; despite being shaded by trees, it can form a nearly continuous canopy cover and attain heights of 3 to 4.5 feet (1 to 1.5 meters). Guineagrass appears to be partially suppressed beneath mature stands of Eucalyptus species, possibly due to shade and the density and chemical composition of the tree litter. Strawberry guava can form dense stands beneath any timber species.

State 4
Invaded Understory State

This state consists of one community phase. It arises by invasion by introduced species of intact native forest (the Reference State) or, in some cases, of native overstory stands from which the original understory has been cleared. Native species are unable to regenerate in the highly competitive understory of introduced plants and eventually die out. With time, large introduced tree species will emerge to replace the native overstory trees and form a new overstory. When this last step has occurred, the site will have transitioned to State 5, Invaded Overstory and Understory State.

Disturbance of the soil and direct damage to native understory plants by introduced ungulates, particularly pigs and cattle, will speed the transition to this state by killing native plants and by creating better germination sites for introduced species.

Restoration to the Reference State or a facsimile of it is possible by fencing the site, removing all ungulates, applying herbicides, and replanting native species when needed. Restoration efforts will be affected depending on the degree of invasion by introduced species and by the species that have invaded the site. Long term weed management and fence maintenance will be necessary.

Community 4.1
Koa - `ohi`a lehua/strawberry guava/kahili ginger

Figure 28. Strawberry guava understory 12/28/06 D Clausnitzer MU956

This community phase has an intact or diminished overstory of large ohia lehua and/or koa trees with a dense understory of introduced shrubs, ferns, vines, grasses, and small trees.

Forest overstory.The overstory consists of ohia lehua and/or koa. Secondary canopy native species are somewhat diminished. Kopiko or wild coffee (Psychotria spp.) is the most common native species remaining in the secondary canopy.

Forest understory. The only native species remaining in the lower canopy levels are a few hapuu (Cibotium glaucum) or hapuu li (Cibotium menziesii), traces of small kopiko, some peperomia (Peperomia spp.) at ground level, an occasional ieie vine (Freycenetia arborea), and a few patches of uluhe or Old World forkedfern. Some small native fern species may be found growing on trees.<br /> <br /> The understory is usually dominated by a nearly impenetrable stand of strawberry guava or waiawi (Psidium cattleianum), which is usually 10 to about 30 feet (3 to 9 meters) tall. Other species indicated on the table grow sparsely beneath the strawberry guava or fill in gaps between it.

State 5
Invaded Overstory and Understory State

This state is comprised of one plant community dominated by introduced species in both the overstory and understory. Understory vegetation usually is very sparse to nonexistent. Remnant individuals of a few native species may persist. This state might be considered a dead end as far as further succession or transition to another state. Restoration to a facsimile of the Reference State could probably be done with expensive and intensive practices followed by long-term weed management. Clearing of the site followed by establishment of an overstory of noninvasive, introduced timber trees with a native understory as an intermediate step to native forest restoration may also be done.

Community 5.1
Strawberry guava - faya tree/kahili ginger

Figure 29. Strawberry guava stand with remnant hapuu 12/6/06 D Clausnitzer MU955

Figure 30. "Prison bar" strawberry guava infestation D Clausnitzer generic photo

Figure 31. Strawberry guava roots exposed by bulldozer D Clausnitzer generic photo

Figure 32. Closeup of exposed strawberry guava root system D Clausnitzer generic photo

It is possible that shifts will eventually occur in the introduced species that dominate the site, particularly if tall stature, competitive tree species are present. This would change the mix of species present and may affect soil chemistry (e.g. nitrate availability or organic matter), but would not represent a transition to another state. Sites that are completely dominated by dense stands of strawberry guava typically show no indications (death or partial death of stands; emergence of potentially taller tree species) of yielding to change in the foreseeable future.

Forest overstory.Depending on local seed sources, invasive trees of moderate stature including strawberry guava, christmasberry, or common guava can dominate a given site initially, but strawberry guava generally will become dominant over time. Taller statured introduced trees including silkoak (Grevillea robusta), albizia or peacocksplume (Falcataria moluccana), and octopus tree (Schefflera actinophylla) can potentially emerge through the canopy of moderate stature species. <br /> <br /> A few remnant ohia lehua and koa trees often remain as emergents above the canopy of introduced species, but no seedling or saplings are likely to be survive.

Forest understory. The tree overstory species are highly competitive and produce dense shade. A variety of introduced understory species is often present but in small numbers. Typical species include Koster’s curse or soapbush (Clidemia hirta), kahili ginger or Kahila garland-lily (Hedychium gardnerianum), and some shade tolerant grass species.<br /> <br /> Scattered individuals of remnant native species such as kopiko, hapuu, and uluhe may remain in the understory.

State 6
Grazed Native Overstory State

This state consists of remnant native tree species forming an overstory with well-managed, relatively weed-free grasses. The overstory may have existed for some time, or may be in the process of forming where residual koa seeds are present in the soil.

Community 6.1
Koa - `ohi`a lehua/guineagrass - hilograss

Figure 33. Native overstory with grazed understory, Hamakua 3/21/08 D Clausnitzer MU970

Figure 34. Young koa emerging through guineagrass, Paauilo mauka 12/28/06 D Clausnitzer MU961

Figure 35. Native akala invading kikuyu grassland Humuula Trail 9/14/09 D Clausnitzer generic photo

This community phase is not common, but it presents good opportunities for restoration of the Reference Community Phase, or a facsimile of it, where it exists. It typically occurs in two forms. The first is where grazing has maintained a non-weedy grass understory beneath a remnant overstory of native trees that has not yet begun to senesce. The second is in grasslands in which a residual seed bank of koa trees existed and cattle were not present to browse the emerging small koa.

In the first form, careful grassland management maintained low weed densities on the site. In both forms, it is advantageous for restoration if neighboring sites do not support high weed densities. It also is advantageous if the grassland is dominated by shorter-statured species such as hilograss or common carpetgrass rather than guineagrass.

In the second form, even tall guineagrass grasslands will eventually be invaded and dominated by introduced woody shrubs and trees.

Forest overstory.The forest overstory is variable, depending on the history of the site. It may consist of: large, scattered koa and/or ohia lehua trees; stands of varying sized trees in varying densities across the site, possibly with ohia lehua, koa, olapa, papala, hapuu, pilo, and other species typical of the Reference Community Phase; or, scattered young koa trees that have managed to germinate from the residual seed bank and emerge through the grass cover.

Forest understory. The understory consists primarily of the common dominant grass species from community phases 2.1 and 2.2 of this ecological site, primarily guineagrass, common carpetgrass, and hilograss. Regeneration of native trees is not possible until livestock have been removed. <br /> <br /> Where lower-stature grasses such as common carpetgrass or hilograss are dominant, it is common to find native fern genera such as Diplazium and Dryopteris spreading through the understory and sometimes achieving high densities. Be careful not to confuse the native hoio or Hawaii twinsorus fern (Diplazium sandwichianum) with the introduced hoio (Diplazium esculentum).

Transition T1A
State 1 to 2

State 1, Reference State, can be converted to State 2, Naturalized Grassland State, by clearing the forest with heavy machinery. Most grasslands in this ecological site were originally cultivated for sugar cane and later converted to grassland. At the highest, coolest elevations of the ecological site, kikuyugrass and/or pangolagrass have been planted. At lower elevations where grasslands are on old sugarcane plantations, guineagrass (a former weed in the plantations) has volunteered and now dominates. Some grasslands may originally have been cleared by large numbers of feral and/or domestic livestock consuming the understory, including tree seedlings and saplings. This process would have left numerous large trees standing if not cut for timber. Large wildfires in the early 20th century also cleared some forest remnants.

Transition T1B
State 1 to 4

State 1, Reference State, can be converted to State 4, Invaded Understory State, by gradual replacement of the understory by shrubs, vines, grasses, and trees that outcompete the native understory species and hinder or prevent their reproduction. Some introduced vines can directly kill native plants, including large trees. This process is accelerated by ungulate foraging that helps introduced weed seeds, enhances weed germination by soil disturbance, and directly destroys native plants.

Transition T1C
State 1 to 6

This transition occurs by either clearing of native forest by machinery or gradual removal of native forest understory and elimination of native plant reproduction by long-term ungulate grazing.

Restoration pathway R2A
State 2 to 1

It may be possible to restore State 2, Naturalized Grassland State, to a plant community resembling State 1, Reference State, by intensive restoration practices followed by long-term maintenance. Control of grasses and any weeds currently in the grassland by mowing and herbicides must precede establishment of native species. Weed control would be a long-term process to maintain the site after establishment. Many weeds are shade-tolerant and would be able to invade the site even after canopy closure of native plants. Domestic and feral ungulates must be fenced out of the restoration site. However, managed grazing by domestic ungulates outside the fence would be useful to manage weedy vegetation outside the perimeter. Increasing shade from restored tree species may eventually cause a shift from C4 (warm-season) grass dominance (typically guineagrass or kikuyugrass) to C4 or C3 (cool-season) shade-tolerant grasses (typically meadow ricegrass, hilograss, or carpetgrass). This shade tolerant grass layer can be very dense and detrimental to establishment of native plants. Suppression of these grasses by herbicides and/or mulch (cardboard works well) until native plant litter begins to cover the grass.

Transition T2A
State 2 to 3

State 2, Naturalized Grassland State, may be converted to State 3, Planted Timber State, by controlling grasses and weedy shrubs by herbicides and/or mowing prior to and after planting of timber species (usually eucalyptus species).

Transition T2B
State 2 to 5

State 2, Naturalized Grassland State, may be converted to State 5, Invaded Overstory and Understory State, by abandonment. Common weed tree species are strawberry guava, christmasberry, faya tree, and common guava. Seeds of these species as well as weedy understory species are spread by mammals and birds.

Restoration pathway R4A
State 4 to 1

State 5, Invaded Understory State, may be restored to a plant community resembling State 1, Reference State. Before restoration of native understory plants, invasive understory plants must be eliminated by herbicide weed control and brush management practices. Also, feral and domestic ungulates must be excluded from the restoration site by a fence, and any remaining ungulates within the fenced site must be eliminated. If feral pigs are present, an intensive, short-term program must be employed to eliminate their population; otherwise, their rate of increase will outpace control efforts. Key native plant species that have been eliminated or greatly reduced in numbers generally must be restored by replanting. Long-term maintenance of the site using herbicides, hand-weeding, mulching, and fence repair is required.

Transition T4A
State 4 to 2

State 4, Invaded Understory State, can be converted to State 2, Naturalized Grassland State, Pasture by mechanical clearing of introduced plants and remnant native understory plants. Native overstory trees may be harvested for timber, knocked down and piled, or left to provide shade for livestock. If leaving large native trees for shade, care must be taken to not damage roots within about 20 feet (6 meters) of the trees. Introduced pasture grass species may then be seeded or sprigged into the site. Herbicide applications will be necessary before and during pasture establishment to control reemerging weed species.

Transition T4B
State 4 to 5

State 4, Invaded Understory State, transitions to State 5, Invaded Overstory and Understory State, over time. The native ohia lehua and koa trees that remain in the overstory are unable to successfully regenerate in the shady and highly competitive environment of the weedy understory. Eventually the native overstory trees die and are replaced by introduced tree species.

Restoration pathway R5A
State 5 to 2

State 5, Invaded Overstory and Understory State, may be restored to State 2, Naturalized Grassland State by mechanical clearing of overstory and understory vegetation, followed by herbicide control of re-emerging invasive species. Introduced grasses may then be seeded or sprigged into the site. Herbicide applications, mowing, and careful grazing practices will be necessary during and after pasture establishment to control reemerging weed species.

Restoration pathway R6A
State 6 to 1

This restoration occurs by removal of ungulates from the site, eventual removal of forage grasses by mowing, mulching, and herbicide application, replanting native species, and eventual natural reproduction by native species.

Transition T6A
State 6 to 2

This transition occurs either by elimination of native tree reproduction by long-term ungulate grazing or by weed invasion of abandoned sites.