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G389 Metrosideros polymorpha - Acacia koa / Freycinetia arborea Lowland Rainforest Group
Type Concept Sentence: This rainforest group occurs on all the main Hawaiian islands except Ni`ihau and Kaho`olawe and is dominated by Metrosideros polymorpha or Acacia koa over a diverse layer of native trees and an understory of native ferns, herbs, shrubs and vines such as Alyxia stellata, Antidesma platyphyllum, Broussaisia arguta, Cheirodendron spp., Cibotium spp., Coprosma spp., Cyrtandra spp., Dicranopteris linearis, Diospyros sandwicensis, Freycinetia arborea, Hedyotis spp., Ilex anomala, Korthalsella spp., Machaerina spp., Melicope spp., Myrsine spp., Peperomia spp., Pittosporum spp., Pritchardia martii, Psychotria spp., Sadleria spp., Smilax melastomifolia, and epiphytes including Astelia menziesiana, Peperomia spp., Adenophorus, Huperzia, and Elaphoglossum spp.
Common (Translated Scientific) Name: `Ohi`a - Koa / `Ie`ie Lowland Rainforest Group
Colloquial Name: Hawaiian Lowland Rainforest
Hierarchy Level: Group
Type Concept: This lowland rainforest group occurs on all the main Hawaiian Islands except Ni`ihau and Kaho`olawe. Lowland wet forests are thought to have been the predominant original vegetation of the windward lowlands on the larger main islands. The canopy is dominated by Metrosideros polymorpha or, in some forests, by Acacia koa where it attains heights up to 40 m. On some islands, this group forms a distinct belt above Acacia-dominated mesic forest. Diversity in the lowland rainforest is high, and Metrosideros and Acacia at times form an emergent layer over a diverse layer of native trees and an understory of native ferns, herbs, shrubs and vines. Important taxa in this rainforest group include Alyxia stellata, Antidesma platyphyllum, Broussaisia arguta, Cheirodendron spp., Cibotium spp., Coprosma spp., Cyrtandra spp., Dicranopteris linearis, Diospyros sandwicensis, Freycinetia arborea, Hedyotis spp., Ilex anomala, Korthalsella spp., Machaerina spp., Melicope spp., Myrsine spp., Peperomia spp., Pittosporum spp., Psychotria spp., Sadleria spp., Smilax melastomifolia, and in some areas Pritchardia spp. Native trees that occur in the understory include Psychotria hawaiiensis and Antidesma platyphyllum. The endemic liana Freycinetia arborea is often abundant in these forests. Species that act as epiphytes include Astelia menziesiana, Peperomia spp., Adenophorus spp., Huperzia spp., and Elaphoglossum spp.
In the upper reaches of the lowland ohi`a forest on the island of Hawai`i, the understory is dominated by tree ferns or Cibotium spp. which form a distinct closed layer beneath the trees. A more open Metrosideros forest with other scattered native trees and a dense ground cover of the indigenous mat-forming Dicranopteris linearis and other related ferns (Diplopterygium pinnatum, Sticherus owhyensis) is seen on steep ridges and valley walls of Kaua`i, O`ahu, Moloka`i, Maui, and the Kohola Mountains of Hawai`i. Freycinetia arborea, Antidesma platyphyllum, Perrottetia, and Bobea spp. are constituents restricted largely to the lowland zone. The group typically occurs on windward slopes high enough to intercept orographic rainfall resulting from rising moist tradewind air, but also occurs in a relatively narrow high precipitation band on the leeward side of the Big Island resulting from Kona storms. Soils vary throughout the island chain, from gray acidic clays on older islands to thin organic mucks over lava flows and ash beds on Hawai`i.
In the upper reaches of the lowland ohi`a forest on the island of Hawai`i, the understory is dominated by tree ferns or Cibotium spp. which form a distinct closed layer beneath the trees. A more open Metrosideros forest with other scattered native trees and a dense ground cover of the indigenous mat-forming Dicranopteris linearis and other related ferns (Diplopterygium pinnatum, Sticherus owhyensis) is seen on steep ridges and valley walls of Kaua`i, O`ahu, Moloka`i, Maui, and the Kohola Mountains of Hawai`i. Freycinetia arborea, Antidesma platyphyllum, Perrottetia, and Bobea spp. are constituents restricted largely to the lowland zone. The group typically occurs on windward slopes high enough to intercept orographic rainfall resulting from rising moist tradewind air, but also occurs in a relatively narrow high precipitation band on the leeward side of the Big Island resulting from Kona storms. Soils vary throughout the island chain, from gray acidic clays on older islands to thin organic mucks over lava flows and ash beds on Hawai`i.
Diagnostic Characteristics: Diagnostic of rainforest group is dominance by Metrosideros polymorpha or Acacia koa over wet indicatory species such as Alyxia stellata, Antidesma platyphyllum, Broussaisia arguta, Cheirodendron spp., Cibotium spp., Coprosma spp., Cyrtandra spp., Dicranopteris linearis, Diospyros sandwicensis, Freycinetia arborea, Hedyotis spp., Ilex anomala, Korthalsella spp., Machaerina spp., Melicope spp., Myrsine spp., Peperomia spp., Pittosporum spp., Pritchardia martii, Psychotria spp., Sadleria spp., Smilax melastomifolia. The present of epiphytes also indicate wet conditions and may include Astelia menziesiana, Peperomia spp., Adenophorus, Huperzia, and Elaphoglossum spp.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: The boundary between the lowland and montane wet forests in Hawai`i is not generally agreed upon by all botanists and ecologists, and it may be variable on different islands. A clear picture of pre-human vegetation is complicated by the extreme disturbance that the lowlands have suffered. Nonetheless, roughly 1000 m elevation marks the transition between the warmer lowlands and the cooler montane zone.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: The open to dense tree canopy attains heights up to 40 m with a variable understory.
Floristics: The canopy is dominated by Metrosideros polymorpha or, in some forests, by Acacia koa where it attains heights up to 40 m. On some islands, this group forms a distinct belt above Acacia-dominated mesic forest. Diversity in the lowland rainforest is high, and Metrosideros and Acacia at times form an emergent layer over a diverse layer of native trees beneath the Metrosideros canopy, and an understory of native ferns, herbs, shrubs and vines, including Alyxia stellata (= Alyxia oliviformis), Antidesma platyphyllum, Broussaisia arguta, Cheirodendron spp., Cibotium spp., Coprosma spp., Cyrtandra spp., Dicranopteris linearis, Diospyros sandwicensis, Freycinetia arborea, Hedyotis spp., Ilex anomala, Korthalsella spp., Machaerina spp., Melicope spp., Myrsine spp., Peperomia spp., Pittosporum spp., Psychotria spp., Sadleria spp., Smilax melastomifolia, and in some areas Pritchardia spp. Native trees that occur in the understory include Psychotria hawaiiensis and Antidesma platyphyllum. The endemic Freycinetia arborea is often abundant in these forests. Species that act as epiphytes include Astelia menziesiana, Peperomia spp., Adenophorus, Huperzia, and Elaphoglossum spp. In the upper reaches of the lowland ohi`a forest on the island of Hawai`i, the understory is dominated by tree ferns or Cibotium spp. which form a distinct closed layer beneath the trees. A more open Metrosideros forest with other scattered native trees and a dense ground cover of the indigenous mat-forming Dicranopteris linearis and other related ferns (Diplopterygium pinnatum, Sticherus owhyensis) is seen on steep ridges and valley walls of Kaua`i, O`ahu, Moloka`i, Maui, and the Kohola Mountains of Hawai`i (Cuddihy and Stone 1990). Freycinetia, Antidesma platyphyllum, Perrottetia, and Bobea are constituents restricted largely to the lowland zone.
Dynamics: The lowland wet forest historically (pre-Polynesian times) was more widespread below 1000 m (3280 feet) elevation on the larger islands in windward areas with deep soils before being subjected to cultivation by Hawaiians. Where lands cultivated by Hawaiians were not subsequently used for agriculture, grazing, or urban development, they were invaded by species of Polynesian introduction, particularly Aleurites moluccanus and by later post-European introductions such as Psidium cattleianum. Disturbances in this group include landslides in wet valleys, flood, lava flows, storms, rat predation, and fire. Major storms, particularly hurricanes, will often open up the tree canopy. Although most of the species found in the tree canopy, subcanopy, and understory will still be present, Dicranopteris linearis and taxa such as Cibotium and Sadleria may temporarily increase in cover because of the increased light levels with the more open canopy. Stands strongly dominated (>90% cover) by non-native species either of Polynesian introduction such as Aleurites moluccanus or post-European introductions such as Psidium cattleianum are classified in ruderal types.
Environmental Description: This group occurs on all the main Hawaiian Islands except Ni`ihau and Kaho`olawe. Lowland wet forests are thought to have been the predominant original vegetation of the windward lowlands on the larger main islands. The group typically occurs on windward slopes high enough to intercept orographic rainfall resulting from rising moist tradewind air, but also occurs in a relatively narrow high precipitation band on the leeward side of the Big Island resulting from Kona storms.
Climate: Climate is moderately wet to very wet (Zones 6 and 7) of the 7 Moisture Zones developed for the Hawaiian Islands by Price et al. (2007). Elevations range from 100-1200 m (328-3935 feet). Annual rainfall ranges from 1500 to over 5000 mm, sometimes less on sheltered sites.
Soil/substrate/hydrology: Soils vary throughout the island chain, from gray acidic clays on older islands to thin organic mucks over lava flows and ash beds on Hawai`i.
Climate: Climate is moderately wet to very wet (Zones 6 and 7) of the 7 Moisture Zones developed for the Hawaiian Islands by Price et al. (2007). Elevations range from 100-1200 m (328-3935 feet). Annual rainfall ranges from 1500 to over 5000 mm, sometimes less on sheltered sites.
Soil/substrate/hydrology: Soils vary throughout the island chain, from gray acidic clays on older islands to thin organic mucks over lava flows and ash beds on Hawai`i.
Geographic Range: This lowland rainforest group occurs on all the main Hawaiian Islands except Ni`ihau and Kaho`olawe.
Nations: US
States/Provinces: HI
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.860732
Confidence Level: Moderate
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
| Type | Name | Database Code | Classification Code |
|---|---|---|---|
| Class | 1 Forest & Woodland Class | C01 | 1 |
| Subclass | 1.A Tropical Forest & Woodland Subclass | S17 | 1.A |
| Formation | 1.A.2 Tropical Lowland Humid Forest Formation | F020 | 1.A.2 |
| Division | 1.A.2.Oa Polynesian Lowland Humid Forest Division | D066 | 1.A.2.Oa |
| Macrogroup | 1.A.2.Oa.1 Hawaiian Lowland Rainforest Macrogroup | M187 | 1.A.2.Oa.1 |
| Group | 1.A.2.Oa.1.b `Ohi`a - Koa / `Ie`ie Lowland Rainforest Group | G389 | 1.A.2.Oa.1.b |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: = Lowland Wet Forest (Gagne and Cuddihy 1990)
- Cuddihy, L. W., and C. P. Stone. 1990. Alteration of native Hawaiian vegetation: Effects of humans, their activities and introductions. University of Hawai''i Press for Cooperative National Parks Resource Studies Unit. Department of Botany, University of Hawai''i at Manoa, Honolulu. 138 pp.
- Faber-Langendoen, D., J. Drake, S. Gawler, M. Hall, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, L. Sneddon, K. Schulz, J. Teague, M. Russo, K. Snow, and P. Comer, editors. 2010-2019a. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]
- Gagne, W. C., and L. W. Cuddihy. 1990. Vegetation. Pages 45-114 in: W. L. Wagner, D. R. Herbst, and S. H. Sohmer, editors. Manual of the Flowering Plants of Hawaii. 2 volumes. University of Hawaii Press, Honolulu.
- Mueller-Dombois, D., and F. R. Fosberg. 1998. Vegetation of the tropical Pacific islands. Springer-Verlag, New York. 733 pp.
- Price, J. P., S. M. Gon, III, J. D. Jacobi, and D. Matsuwaki. 2007. Mapping plant species ranges in the Hawaiian Islands: Developing a methodology and associated GIS layers. Hawai''i Cooperative Studies Unit. Technical Report HCSU-008. Pacific Aquaculture and Coastal Resources Center (PACRC), University of Hawai''i, Hilo. 58 pp., includes 16 figures and 6 tables.
- Wagner, W. L., D. R. Herbst, and S. H. Sohmer. 1999. Manual of the flowering plants of Hawaii. Revised edition. Volumes 1 and 2. University of Hawaii Press and Bishop Museum Press, Honolulu. 1919 pp.