Included here is Central America south of Mexico including Guatemala, Honduras, San Salvador, Nicaragua, Costa Rica and much of Panama.

Costa Rican Montane Bamboo-Oak Forest

On the Cordillera de Talamanica these forests range in altitude from 2200-3100 m and can be divided into several sub-formations. In general, however, they can be broadly categorized into forests characterized by either the endemic Quercus costaricensis or the endemic Quercus copeyensis (Fagaceae).  Quercus costaricensis forest often has five or more vertical layers and can reach heights of up to 30 m. A sub canopy layer is often characterized by the endemic small tree Myrsine pittieri (Myrsinaceae), while other sub canopy trees include Clethra gelida, Drimys grandensis, Oreopanax capitatus, Weinmannia trianae and the endemic Didymopanax pittieri (Araliaceae), Ilex vulcanicola (Aquifoliaceae), Rhamnus oreodendron (Rhamnaceae), Symplocos austin-smithii (Symplocaceae), Vaccinium consanguineum (Ericaceae) and Viburnum costaricanum (Caprifoliaceae). The shrub layer is typically dominated by species of the bamboo genus Chusquea and the endemic shrub Pernettya coriacea (Ericaceae) and can reach heights of 5 m. Below this the herb layer can grow up to 1 m tall and is typically characterized by ferns and terrestrial bromeliads. Finally there is usually a conspicuous bryophyte ground layer often dominated by peat forming Sphagnum species. In slightly more humid conditions the endemic Quercus copeyensis becomes co-dominant with Q. costaricensis. Other associated trees include Podocarpus oleifolius, Prumnopitys standleyi, Weinmannia pinnata and the endemic Ocotea austinii (Lauraceae). In places the canopy can reach 40 m. The sub canopy ranges from 15-25 m and is again rich in endemic taxa such as Ilex lamprophylla var. discolor (Aquifoliaceae), Miconia pittieri (Melastomataceae), Nectandra salicina (Lauraceae), Prunus annularis (Rosaceae), Zanthoxylum scheryi (Rutaceae) and others. Chusquea bamboos again dominate the shrub layer and there are rich herb and ground layers. In areas where cloud cover becomes an important factor (the cloud belt) Quercus copeyensis usually becomes the dominant canopy tree and epiphytes become a lot more conspicuous often blanketing trees. Here subcanopy trees grow to about 25 m and include endemic species such as Miconia costaricensis (Melastomataceae), Cornus disciflora (Cornaceae), Phoebe pittieri (Lauraceae) together with many of the aforementioned species. In the shrub layer the palm Geonoma hoffmanniana becomes particularly important together with Chusquea bamboos (including C. foliosa and C. patens), several tree ferns, the broad-leaved bamboo Aulonemia viscose, and the endemic shrub Cavendishia crassifolia (Ericaceae). The herb layer is rich in ferns and herbs such as Maianthemum paniculatum and the endemic Begonia udisilvestris (Begoniaceae). Finally in places were conditions are slightly warmer and possibly drier these forests become co-dominated by the endemic white-barked Quercus copeyensis and the endemic black-barked Quercus seemanni (Fagaceae). The sub-canopy here has many species in common with other sub-formations, but also commonly includes the endemic Oreopanax oerstedianum (Araliaceae). Chusquea is again dominant in the shrub layer together with species such as Fuchsia microphylla and the endemic Psammisia ramiflora (Ericaceae). At ground level herbs and ferns dominate with Adiantum concinnatum, Bomarea tenerum, Pteris muricella and the endemic Anthurium concinnatum (Araceae), Centropogon costaricae (Campanulaceae) and Verbesina oerstediana (Asteraceae) being particularly common.

Guatemalan High Elevation Conifer Forests

In the Sierra de los Cuchumatanes and Cadena Volcanica areas these upland conifer forests can be broadly divided in to pine and fir forests. Pine forest dominated by Pinus hartwegii appears to be the main climatic climax community in the altitudinal range of 2800-4000 m. However, these forests are far from homogenous and can be divided into several sub-formations or communities. In places the herb layer is dominated by Agrostis tolucensis and Relbunium microphyllum while less common species include Eryngium scaposum, Plantago tubulosa, Senecio warcewiczii and the endemic Lepechinia schiedeana (Lamiaceae). This type of forests can be found on both flat and undulating terrain but forest with herb layers dominated by Agrostis exserta and Werneria nubigena are confined to undulating areas. Here there is usually a low herb layer with Eryngium cymosa, Gentiana pumilio and Werneria nubigena and tall herb layer with Agrostis exserta and Helenium integrifolium. On steep the slopes of Cadena Volcanica, open, monodominant stands of Pinus hartwegia occur that can reach heights of 20 m or more. Here the under storey if largely composed of a bunch grass layer with Calamagrostis vulcanica and Lupinus montanus and a ground layer dominated by Lachemilla vulcanica. Other species include Castilleja integrifolia, Gnaphalium salicifolium and the endemic Senecio oerstedianus (Asteraceae). On less steep slopes Pinus hartwegii is joined by the sporadic occurrence of trees such as Alnus firmifolia and the endemic Buddleja magalocephala (Scrophulariaceae) and a shrub layer comprising Holodiscus argenteus, Rubus trilobata and the endemic Juniperus standleyi (Cupressaceae), which can reach heights of up to 6 m. Most of the pine trees in this zone appear to be infested by the hemiparasitic plant Arceuthobium globosum (Loranthaceae). Other endemic species associated with these conifer forests include Cerastium guatemalense (Caryophyllaceae), Cirsium skutchii, Hieracium guatemalensis, Eupatoria nubivagum, Senecio nubivalus (Asteraceae), Cardamine eremita (Brassicaceae) and Poa venosa (Poaceae). Fir forests dominted by the endemic Abies guatemalensis (Pinaceae) are characteristic of very steep slopes ranging in elevation from about 2800-3400 m. These are dense forests that grow to a height of 30 m or so. Other characteristic species include Sabazia pinetiorum. A distinct shrub layer with species such as Rubus trilobus, Senecio callosus and Tetragyron orizabense is usually present but a conspicuous herb layer is largely absent. Other characteristic species include Cheilanthes chaerophylla, Salvia excelsa, Trifolium amable and the endemic Arenaria guatemalensis (Caryophyllaceae).

References

Andersen, U. S., Córdova, J. P. P., Sorensen, M., Kollmann, J. 2006. Conservation and utilisation of Abies guatemalensis Rehder (Pinaceae) – an endangered endemic conifer in Central America. Biodiversity and Conservation, 15: 3131-3151.

Hartshorn, G. S. 1989. Tropical and subtropical vegetation of meso-America. In: North American Terrestrial Vegetation. Eds. M. G. Barbour and W. D. Billings. Cambridge University Press.

Heaney, A. & Procter, J. 1990. Preliminary studies on the forest structure and floristics on Volcán Barva, Costa Rica. Journal of Tropical Ecology, 6: 307-320.

Isleba, G. A., Velázquez, A. & Cleef, A. M. 1995. High elevation coniferous vegetation of Guatemala. A phytosociological approach. Vegetatio, 116: 7-23.

Janzen, D. H. 1983. Costa Rican Natural History. The University of Chicago Press.

Keppelle, M., Cleef. A. M. & Chaverri, A. 1989. Phytogeography of montane Chusquea - Quercus forest, Cordillera de Talamanca, Costa Rica. Brenesia, 32: 73-105.

Keppelle, M., Cleef. A. M. & Chaverri, A. 1992. Phytogeography of Talamanca montane Quercus forest, Costa Rica. Journal of Biogeography, 19: 299-315.

Leopold, A. S. 1950. Vegetation zones of Mexico. Ecology, 31: 507-518.

Lieberman, D., Lieberman, M., Peralta, P. & Hartshorn, G. S. 1996. Tropical forest structure and composition on a large-scale altitudinal gradient in Costa Rica. Journal of Ecology, 84: 137-152.

Myers, C. W. 1969. The ecological geography of cloud forest in Panama. American Museum Novitiates, 2396: 1-52.

Sawyer, J. O. & Lindsey, A. A. 1971. Vegetation of life zones in Costa Rica. Indiana Academy of Science, Monograph 2: 1-214.

Seymour, F. C. 1980. A checklist of the vascular plants of Nicaragua 1968-1976. Phytological Memoirs, 1: 1-314.

Zuchowski, W. 2007. Tropical Plants of Costa Rica. A Zona Tropical Publication from Comstock Publishing Associates.