Name:
Metrosideros polymorpha - Cheirodendron spp. / Cibotium spp. Hawaiian Montane Rainforest & Cloud Forest Group
Reference:
NatureServe Biotics 2019
Description:
This montane forest group occurs on all the high Hawaiian Islands and is composed of rainforests and cloud forests that vary in height, structural complexity and species richness. Rainforests are often dominated by <i>Metrosideros polymorpha</i> and <i>Cibotium</i> spp., or by a tall, well-stratified canopy of <i>Acacia koa</i>. At higher elevations, <i>Metrosideros</i> forms a floristically relatively simple canopy that is 5-8 m tall and may be as low as 2 m in poorly drained areas and along bog margins. Montane rainforests indicator species include <i>Alyxia stellata, Cheirodendron dominii, Cheirodendron platyphyllum, Cheirodendron trigynum</i>, and <i>Ilex anomala</i>. Common codominant and associated species include <i>Astelia menziesiana, Broussaisia arguta, Carex alligata, Clermontia</i> spp., <i>Coprosma foliosa, Cyrtandra</i> spp., <i>Dicranopteris</i> spp., <i>Psychotria</i> spp., <i>Pteridium aquilinum, Rubus hawaiensis, Urera glabra</i>, and <i>Vaccinium calycinum</i>. Epiphytic mosses, ferns, and other plants are common and include <i>Astelia menziesiana, Carex alligata, Elaphoglossum</i> spp., <i>Metrosideros polymorpha, Peperomia</i> spp., and <i>Vaccinium calycinum</i>. There is some overlap in concept between montane rainforests and cloud forests with similar species composition; the latter tend to have a low-statured tree canopy because of near-daily, ground-level clouds and fog drip that develop highly leached, saturated substrates that limit tree growth. However, cloud forests generally have higher floristic diversity and support more epiphytes than montane rainforests. Stands are often dominated by stunted or gnarled, lichen-covered <i>Metrosideros polymorpha</i> and <i>Cheirodendron</i> spp. trees, which form a low to medium-height canopy. Subdominant tree species include <i>Alyxia stellata, Ilex anomala</i>, and shrubs <i>Clermontia</i> spp., <i>Cyanea</i> spp., <i>Dubautia platyphylla, Korthalsella</i> spp., <i>Myrsine</i> spp., <i>Trematolobelia</i> spp., <i>Smilax melastomifolia, Stenogyne</i> spp., <i>Phyllostegia</i> spp., and <i>Vaccinium</i> sp. Stands frequently support a large mass of epiphytic mosses, ferns, and other plants. Species that act as epiphytes include <i>Astelia menziesiana, Peperomia</i> spp., and thick mats of bryophytes. Forbs include <i>Astelia, Adenophorus, Cibotium</i> spp., <i>Dicranopteris linearis</i> (most common), and <i>Elaphoglossum</i> spp. Montane rainforest and cloud forests occur between 1000 and 2200 m (3280-7020 feet) elevation. However, cloud forests typically occur on wind-exposed upper slopes that do not exceed 1830 m (6000 feet) elevation. The climate is warm, tropical. Stands occur on windward areas that receive evenly distributed orographically derived rainfall exceeding 2500 mm (98 inches) annually. Montane rainforest stands also occur in a relatively narrow high precipitation band on the leeward side of the Big Island resulting from Kona storms. There is frequent afternoon fog that generates fog drip. Cloud forests are restricted to windward aspects and are defined by almost daily presence of ground-level clouds which contribute significant fog water (fog drip) to total annual precipitation (up to 1073 mm [42 inches]). Regular fog drip sustains relatively constant streamflow and shallow groundwater hydrology in montane forests, particularly during dry seasons. Soils generally have a gley horizon 10 to 70 cm (4-28 inches) deep, underlain by lateritic weathered basalt and overlain with organic hummus ranging from 10 to 30 cm (4-12 inches) deep. Montane cloud forests tend to occur on older volcanic substrates that are nutrient-poor and lateritic due to leaching. Montane rainforests merge with ~Hawaiian Lowland Rainforest Group (G389)$$ at the lower elevational limit. At the upper elevational limit on Hawai`i and Maui, they quickly grade into <i>Acacia / Sophora</i> forest and other mesic communities.
Accession Code:
urn:lsid:vegbank.org:commConcept:40121-{0BFA8252-7BEE-4EC6-AAFD-6A7C7A0AEB7E}
Plot-observations of this Community Concept:
0
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