Cloud forests are believed to have retreated and advanced during successive geological eras, and their species adapted to warm and wet conditions were replaced by more cold-tolerant or drought-tolerant sclerophyll plant communities.
[citation needed] Although some remnants of archaic flora, including species and genera extinct in the rest of the world, have persisted as endemic to such coastal mountain and shelter sites, their biodiversity was reduced.
Since laurel forests are archaic populations that diversified as a result of isolation on islands and tropical mountains, their presence is a key to dating climatic history.
[9] Some forests are dominated by Lauraceae, while in others evergreen laurophyll trees of the beech family (Fagaceae) are predominant, including ring-cupped oaks (Quercus subgenus Cyclobalanopsis), chinquapin (Castanopsis) and tanoak (Lithocarpus).
Some other common trees and large shrub species of subtropical forests are Semecarpus anacardium, Crateva unilocularis, Trewia nudiflora, Premna interrupta, Vietnam elm (Ulmus lancifolia), Ulmus chumlia, Glochidion velutinum, beautyberry (Callicarpa arborea), Indian mahogany (Toona ciliata), fig tree (Ficus spp.
), Mahosama similicifolia, Trevesia palmata, brushholly (Xylosma longifolium), false nettle (Boehmeria rugulosa), Heptapleurum venulosum, Casearia graveilens, Actinodaphne reticulata, Sapium insigne, Nepalese alder (Alnus nepalensis), marlberry (Ardisia thyrsiflora), holly (Ilex spp), Macaranga pustulata, Trichilia cannoroides, hackberry (Celtis tetrandra), Wenlendia puberula, Saurauia nepalensis, ring-cupped oak (Quercus glauca), Ziziphus incurva, Camellia kissi, Hymenodictyon flaccidum, Maytenus thomsonii, winged prickly ash (Zanthoxylum armatum), Eurya acuminata, matipo (Myrsine semiserrata), Sloanea tomentosa, Hydrangea aspera, Symplocos spp., and Cleyera spp.
Nepalese alder (Alnus nepalensis), a pioneer tree species, grows gregariously and forms pure patches of forests on newly exposed slopes, in gullies, beside rivers, and in other moist places.
This zone is habitat for many other important tree and large shrub species such as pindrow fir (Abies pindrow), East Himalayan fir (Abies spectabilis), Acer campbellii, Acer pectinatum, Himalayan birch (Betula utilis), Betula alnoides, boxwood (Buxus rugulosa), Himalayan flowering dogwood (Cornus capitata), hazel (Corylus ferox), Deutzia staminea, spindle (Euonymus tingens), Siberian ginseng (Acanthopanax cissifolius), Coriaria terminalis ash (Fraxinus macrantha), Dodecadenia grandiflora, Eurya cerasifolia, Hydrangea heteromala, Ilex dipyrena, privet (Ligustrum spp.
), Litsea elongata, common walnut (Juglans regia), Lichelia doltsopa, Myrsine capitallata, Neolitsea umbrosa, mock-orange (Philadelphus tomentosus), sweet olive (Osmanthus fragrans), Himalayan bird cherry (Prunus cornuta), and Viburnum continifolium.
[12] Laurel forests occupy the humid tropical highlands of the Malay Peninsula, Greater Sunda Islands, and Philippines above 1,000 m (3,300 ft) elevation.
Some of these species went globally extinct (e.g. laurophyll Quercus), others survived in the Atlantic islands (e.g. Ocotea), or in other continents (e.g. Magnolia, Liquidambar) and some adapted to the cooler and drier climate of Europe and persisted as relicts in places with high mean annual precipitation or in particular river basins, such as sweet bay (Laurus nobilis) and European holly (Ilex aquifolium), which are fairly widespread around the Mediterranean basin.
The portuguese laurel cherry (Prunus lusitanica) is the only tree that survives as a relict in some Iberian riversides, especially in the western part of the peninsula.
This species survives natively in Morocco, Algeria, Tunisia, Spain, Portugal, Italy, Greece, the Balkans, and the Mediterranean islands.
Tree heath (Erica arborea) grows in southern Europe, but without reaching the dimensions observed in the temperate evergreen forest of Macaronesia or North Africa.
The broad-leaved Rhododendron ponticum baeticum and/or Rhamnus frangula baetica still persist in humid microclimates, such as stream valleys, in the provinces of Cádiz and Málaga in Spain,[21] in the Portuguese Serra de Monchique, and the Rif Mountains of Morocco.
[22][verification needed] The Parque Natural de Los Alcornocales has the biggest and best preserved relicts of Laurisilva in Western Europe.
[23] Although the Atlantic laurisilva is more abundant in the Macaronesian archipelagos, where the weather has fluctuated little since the Tertiary, there are small representations and some species contribution to the oceanic and Mediterranean ecoregions of Europe, Asia minor and west and north of Africa, where microclimates in the coastal mountain ranges form inland "islands" favorable to the persistence of laurel forests.
In Europe the laurel forest has been badly damaged by timber harvesting, by fire (both accidental and deliberate to open fields for crops), by the introduction of exotic animal and plant species that have displaced the original cover, and by replacement with arable fields, exotic timber plantations, cattle pastures, and golf courses and tourist facilities.
[9] The Afromontane laurel forests describe the plant and animal species common to the mountains of Africa and the southern Arabian Peninsula.
The main species of the Afromontane forests include the broadleaf canopy trees of genus Beilschmiedia, with Apodytes dimidiata, Ilex mitis, Nuxia congesta, N. floribunda, Kiggelaria africana, Prunus africana, Rapanea melanophloeos, Halleria lucida, Ocotea bullata, and Xymalos monospora, along with the emergent conifers Podocarpus latifolius and Afrocarpus falcatus.
Tree species include: Real Yellowwood (Podocarpus latifolius), Outeniqua Yellowwood (Podocarpus falcatus), White Witchhazel (Trichocladus ellipticus), Rhus chirendensis, Curtisia dentata, Calodendrum capense, Apodytes dimidiata, Halleria lucida, Ilex mitis, Kiggelaria africana, Nuxia floribunda, Xymalos monospora, and Ocotea bullata.
elongata), Pigs-ears (Centella asiatica), Cyperus albostriatus, Polypodium polypodioides, Polystichum tuctuosum, Streptocarpus rexii, and Plectranthus spp.
According to the recent study by Box and Fujiwara (Evergreen Broadleaved Forests of the Southeastern United States: Preliminary Description), laurel forests occur in patches in the southeastern United States from southeast Virginia southward to Florida, and west to Texas, mostly along the coast and coastal plain of the Gulf and south Atlantic coast.
In many portions of the coastal plain, a low-lying mosaic topography of white sand, silt, and limestone (mostly in Florida), separate these laurel forests.
Gordonia lasianthus, Ilex opaca and Osmanthus americanus also may occur as canopy co-dominant in coastal dune forests, with Cliftonia monophylla and Vaccinium arboreum as a dense evergreen understory (Box and Fujiwara 1988).
They occur discontinuously from Venezuela to northwestern Argentina including in Brazil, Bolivia, Chile, Colombia, Ecuador, and Peru, usually in the Sub-Andean Sierras.
[28] The inland Alto Paraná Atlantic forests, which occupy portions of the Brazilian Highlands in southern Brazil and adjacent parts of Argentina and Paraguay, are semi-deciduous.
The Valdivian temperate rain forests, or Laurisilva Valdiviana, occupy southern Chile and Argentina from the Pacific Ocean to the Andes between 38° and 45° latitude.
Laurel forest appears on mountains of the coastal strip of New South Wales in Australia, New Guinea, New Caledonia, Tasmania, and New Zealand.
As it collided with the Pacific Plate on its northward journey, the high mountain ranges of central New Guinea emerged around 5 million years ago.