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G406 Metrosideros polymorpha - Sophora chrysophylla - Chamaesyce olowaluana Montane-Subalpine Dry Forest & Woodland Group
Type Concept Sentence: This dry montane to subalpine forest and woodland group occurs on the larger Hawaiian Islands and is characterized by an open to dense tree layer dominated or codominated by Acacia koa, Chamaesyce celastroides, Chamaesyce olowaluana, Myoporum sandwicense, Metrosideros polymorpha, or Sophora chrysophylla.
Common (Translated Scientific) Name: `Ohi`a - Mamani - Akoko Dry Montane-Subalpine Forest & Woodland Group
Colloquial Name: Hawaiian Montane-Subalpine Dry Forest & Woodland
Hierarchy Level: Group
Type Concept: This montane to subalpine forest and woodland group occurs on the larger Hawaiian Islands and is characterized by an open to dense tree layer dominated or codominated by Metrosideros polymorpha, and other trees such as Acacia koa, Chamaesyce celastroides, Chamaesyce olowaluana, Myoporum sandwicense, or Sophora chrysophylla. Diagnostic taxa for this group are Chamaesyce olowaluana, Sophora chrysophylla, and species of Exocarpos (shrubs). Other trees include Myrsine lanaiensis, Santalum spp., and Zanthoxylum hawaiiense. Understory is frequently composed of Chenopodium oahuense, Dodonaea viscosa, Styphelia tameiameiae, and Vaccinium spp. that form a sparse to moderately dense shrub layer up to 3 m tall. Native graminoids (e.g., Gahnia spp.) usually have less than 10% cover and ferns (e.g., Pteridium aquilinum) are often present, but contribute low cover, especially at higher elevations. Native grasses include Eragrostis atropioides. Fire-adapted exotic grasses such as Pennisetum setaceum are invasive and threaten these dry shrublands by increasing fire intensity, frequency and size. The exotic rosette forb Verbascum thapsus is common in many stands. Stands occur on dry slopes of higher mountains of Maui and Hawai`i, from 1000-2900 m (3280-9510 feet) elevation. An inversion layer of warmer air forms 50-70% of the time between 1600 and 3000 m that dramatically reduces precipitation at higher elevations. This is because the wet tradewinds generally do not rise above 1900 m (6230 feet) and are deflected around the mountains, leaving upper slopes too dry to support rainforests. Stands also occur at lower elevations on the leeward sides of islands where there is a strong rainshadow effect. Annual rainfall is generally 300-1200 mm. Many sites are wind-exposed. Substrates include cinder, well-drained, sandy loam soils derived from volcanic ash, and weathered `a`â or pâhoehoe basaltic lava with little soil development.
Diagnostic Characteristics: This group occurs at elevations above 1000 m and is characterized by an open to dense tree layer dominated or codominated by Acacia koa, Chamaesyce celastroides, Chamaesyce olowaluana, Metrosideros polymorpha, Myoporum sandwicense, or Sophora chrysophylla. Diagnostic taxa for this group are Chamaesyce olowaluana, Sophora chrysophylla, and species of Exocarpos and other dry-site indicators. Many stands occur in the saddle area between Mauna Kea and Mauna Loa.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: No Data Available
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: This montane to subalpine forest and woodland group is characterized by an open to dense tree layer dominated or codominated by Acacia koa, Chamaesyce celastroides, Chamaesyce olowaluana, Metrosideros polymorpha, Myoporum sandwicense, or Sophora chrysophylla. Acacia koa forests are tallest (up to 18 m), and Sophora - Myoporum and Chamaesyce forests range from 3-5 m tall, and up to 10 m in some places. Diagnostic taxa for this group are Chamaesyce olowaluana, Sophora chrysophylla, and species of Exocarpos shrubs. Other trees include Myrsine lanaiensis, Santalum spp., and Zanthoxylum hawaiiense. Dodonaea viscosa, Styphelia tameiameiae, Chenopodium oahuense, and Vaccinium spp. frequently form a sparse to moderately dense shrub layer up to 3 m tall. Other shrubs may include Bidens menziesii, Coprosma ernodeoides, Dubautia ciliolata, Dubautia linearis, Geranium cuneatum, Geranium multiflorum, Osteomeles anthyllidifolia, Silene spp., and Tetramolopium spp. Native graminoids(e.g., Gahnia spp., Eragrostis atropioides) usually have less than 10% cover and ferns (e.g., Pteridium aquilinum) are present but contribute low cover, especially at higher elevations. Fire-adapted exotic grasses such as Pennisetum setaceum are invasive and threaten these dry woodlands by increasing fire intensity, frequency and size (Castillo 1997). The exotic rosette forb Verbascum thapsus is common in many stands.
Dynamics: This is a structurally diverse group that varies depending on pioneer substrates. On basalt lava, Metrosideros polymorpha is the pioneer species with a mixture of sparse ferns, grasses, and shrubs. Then shrubs such as Dodonaea viscosa, Styphelia tameiameiae, Chenopodium oahuense, and Vaccinium spp. form a layer with shrubby and tree form Metrosideros polymorpha. As more ash blows in, other tree species may colonize, such as Acacia koa, Chamaesyce celastroides, Chamaesyce olowaluana, Myoporum sandwicense, or Sophora chrysophylla, forming an open tree canopy and eventually a closed tree canopy. Bird dispersal of shrub and trees seeds beneath colonizing Metrosideros trees is evident.
On cinder and ash deposits, shrubs such as Chenopodium oahuense, Dodonaea viscosa, Styphelia tameiameiae, grasses and ferns colonize barren substrates. Sophora chrysophylla and Myoporum sandwicense become established as the shrub layer closes and stands resemble climax dry shrubland with scattered trees. Grasses may be present with up to 40% cover. Sophora chrysophylla and Myoporum sandwicense continue to grow and form an open tree canopy with a moderately dense shrub layer and a grass layer (up to 20% cover). Eventually the Sophora chrysophylla and Myoporum sandwicense tree canopy closes. This late-seral tree canopy may become mixed with or in time dominated by Acacia koa, Chamaesyce celastroides, or Chamaesyce olowaluana.
On cinder and ash deposits, shrubs such as Chenopodium oahuense, Dodonaea viscosa, Styphelia tameiameiae, grasses and ferns colonize barren substrates. Sophora chrysophylla and Myoporum sandwicense become established as the shrub layer closes and stands resemble climax dry shrubland with scattered trees. Grasses may be present with up to 40% cover. Sophora chrysophylla and Myoporum sandwicense continue to grow and form an open tree canopy with a moderately dense shrub layer and a grass layer (up to 20% cover). Eventually the Sophora chrysophylla and Myoporum sandwicense tree canopy closes. This late-seral tree canopy may become mixed with or in time dominated by Acacia koa, Chamaesyce celastroides, or Chamaesyce olowaluana.
Environmental Description: This tropical montane to subalpine group occurs on dry slopes of higher mountains of Maui and Hawai`i, from 1000-2900 m (3280-9510 feet) elevation. An inversion layer of warmer air forms 50-70% of the time between 1600 and 3000 m that dramatically reduces precipitation at higher elevations (Gagne and Cuddihy 1990). This is because the wet tradewinds generally do not rise above 1900 m (6230 feet) and are deflected around the mountains, leaving upper slopes too dry to support rainforests (Mueller-Dombois and Fosberg 1998). Stands also occur at lower elevations on the leeward sides of islands where there is a strong rainshadow effect. This woodland group occurs within the very dry and moderately dry zones (Zones 2 and 3) of the 7 Moisture Zones developed for the Hawaiian Islands by Price et al. (2007). Many sites are wind-exposed.
Climate: Climate is tropical, with moderate temperature depending on elevation that is very dry to moderately dry. Annual rainfall is generally 300-1200 mm.
Soil/substrate/hydrology: Substrates include cinder, well-drained, sandy loam soils derived from volcanic ash, and weathered `a`â or pâhoehoe basaltic lava with little soil development.
Climate: Climate is tropical, with moderate temperature depending on elevation that is very dry to moderately dry. Annual rainfall is generally 300-1200 mm.
Soil/substrate/hydrology: Substrates include cinder, well-drained, sandy loam soils derived from volcanic ash, and weathered `a`â or pâhoehoe basaltic lava with little soil development.
Geographic Range: This montane to subalpine forest and woodland group occurs on the larger Hawaiian Islands on drier leeward slopes and in the dry saddle area between Mauna Kea and Mauna Loa on Hawai`i.
Nations: US
States/Provinces: HI
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.860766
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.1 Tropical Dry Forest & Woodland Formation | F003 | 1.A.1 |
| Division | 1.A.1.Oc Polynesian Dry Forest & Woodland Division | D072 | 1.A.1.Oc |
| Macrogroup | 1.A.1.Oc.1 Hawaiian Dry Forest & Woodland Macrogroup | M210 | 1.A.1.Oc.1 |
| Group | 1.A.1.Oc.1.b `Ohi`a - Mamani - Akoko Dry Montane-Subalpine Forest & Woodland Group | G406 | 1.A.1.Oc.1.b |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: > Chamaesyce Treeland (Shaw and Castillo 1997)
> Myoporum-Chamaesyce Treeland (Shaw and Castillo 1997)
> Sophora-Myoporum Parkland (Mueller-Dombois and Fosberg 1998)
> Akoko (Chamaesyce) Forest (Gagne and Cuddihy 1990)
> Intermediate Metrosideros Mixed Treeland (Shaw and Castillo 1997)
> Koa/Mamame (Acacia/Sophora) Forest (Gagne and Cuddihy 1990)
= Montane Dry Forest (Gagne and Cuddihy 1990)
> Ohi`a (Metrosideros) Montane Dry Forest (Gagne and Cuddihy 1990)
> Ohi`a (Metrosideros) Subalpine Forest (Gagne and Cuddihy 1990)
> Open Metrosideros Treeland with dense shrub understory (Shaw and Castillo 1997)
> Open Metrosideros Treeland with sparse shrub understory (Shaw and Castillo 1997)
= Subalpine Dry Forest (Gagne and Cuddihy 1990)
> Myoporum-Chamaesyce Treeland (Shaw and Castillo 1997)
> Sophora-Myoporum Parkland (Mueller-Dombois and Fosberg 1998)
> Akoko (Chamaesyce) Forest (Gagne and Cuddihy 1990)
> Intermediate Metrosideros Mixed Treeland (Shaw and Castillo 1997)
> Koa/Mamame (Acacia/Sophora) Forest (Gagne and Cuddihy 1990)
= Montane Dry Forest (Gagne and Cuddihy 1990)
> Ohi`a (Metrosideros) Montane Dry Forest (Gagne and Cuddihy 1990)
> Ohi`a (Metrosideros) Subalpine Forest (Gagne and Cuddihy 1990)
> Open Metrosideros Treeland with dense shrub understory (Shaw and Castillo 1997)
> Open Metrosideros Treeland with sparse shrub understory (Shaw and Castillo 1997)
= Subalpine Dry Forest (Gagne and Cuddihy 1990)
- Castillo, J. M. 1997. Control of Pennisetum setaceum (Forssk.) Chiov. in native Hawaiian dry upland ecosystems. Unpublished thesis, Department of Forestry, Colorado State University, Fort Collins. 35 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.
- Shaw, R. B., and J. M. Castillo. 1997. Plant communities of Pohakuloa Training Area, Hawaii. Center for Ecological Management of Military Lands. Department of Forest Sciences. Colorado State University. Fort Collins.
- 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.