Geography of Korea: I. Natural Environment > 4. Soil and Vegetation > 2) Vegetation
(1) Warm temperate forest zone (evergreen broadleaf zone)
In Korea, the warm temperate forest zone extends in the interior as far as 35˚N latitude, while on the coasts it extends to 35˚30’N latitude. In the southern coastal and coastal island areas where annual mean temperatures average 14˚C or above, one finds a mixture of temperate broadleaf evergreens and deciduous broadleaf trees. In terms of species, this zone has Quercus acuta (Japanese evergreen oak), Quercus myrsinaefolia (bamboo-leaf oak), the sieboldii variety of the Castanopsis cuspidate (a species of castanopsis), Cinnamomum camphora (camphor), Camellia japonica (camellia), Quercus glauca (ring-cupped oak or glaucous-leaf oak), Cinnamomum japonicum (Japanese cinnamon), Machilus thunbergii (a species of evergreen shrub), Neolitsea sericea (a medium-sized evergreen tree), and Euonymus japonicas (an evergreen shrub), while in terms of vines there is the Piper kadsura (Japanese pepper), Trachelospermum asiaticum (Asiatic jasmine), Kadsura japonica (Kadsura vine), Ficus thunbergii and Stauntonia hexaphylla.
(2) Temperate forest zone (deciduous broadleaf zone)
With the exception of high alpine regions, the temperate forest region is found between the 35˚N and 43˚N latitudes. Typical to the species found here are Acer palmatum (maple), Quercus mongolica (Mongolian oak), Quercus dentate (Japanese emperor oak), Quercus serrata (Bao Li), Quercus aliena (Oriental white oak), Betula platyphylla var. japonica (Japanese white birch), Zelkova serrata (Japanese elm), Styrax japonicas (Japanese snowbell), Styrax obassia (a species of flowering plant), Carpinus tschonoskii (Asian hornbeam), Lindera erythrocarpa (red-fruited spice bush), Lindera obtusiloba (blunt-lobed spice bush), and the Acer pictum subspecies Mono (painted maple). The annual mean temperature of the deciduous broadleaf forest region ranges between 5˚C and 14˚C, and it can be sub-divided into southern, central, and northern subzones, according to geographic and location and botanical composition.
The southern temperate forest subzone lies between 35˚N and 36˚N latitude, though it stretches as far as the 38˚N latitude along the eastern coast and to 37˚30’N on the west coast. Main species found in this region include ones typical of the temperate forest zone, including the Carpinus tschonoskii (Asian hornbeam), Lindera erythrocarpa (red-fruited spice bush), Meliosma myriantha (a flowering shrub), Pourthiaea villosa (Oriental photinia), Zanthoxylum schinifolium (Szechuan pepper), Acer palmatum (maple), Sapium japonicum (Neoshirakia ), Platycarya strobilacea (Platycarya), Celtis sinensis (Chinese hackberry), and the Lindera glauca (greyblue spice bush), as well as some common to the warm temperate forest zone, such as the Euonymus japonicas (an evergreen shrub), Euonymus fortunei var. radicans (fortune’s spindle), Daphniphyllum macropodum (daphniphyllum), and varieties of bamboo like Phyllostachys bambusoides (madake or giant timber bamboo) and Sinoarundinaria nigra var. henonis (black bamboo), and the warm temperate zone Pinus densiflora (Japanese red pine), Cephalotaxus koreana (Korean plum yew), and Pinus thunbergii (black pine).
The central temperate forest subzone stretches to 40˚N latitude on the eastern coast, 39˚N on the western, and to 38˚30’N in the interior. Primary deciduous broadleaf species found here include Zelkova serrata (Japanese elm), Styrax japonicas (Japanese snowbell), Quercus mongolica (Mongolian oak), Quercus serrata (Bao Li), Quercus aliena (Oriental white oak), Quercus urticaefolia, Lindera glauca (greyblue spice bush), Lindera obtusiloba (blunt-lobed spice bush), and the Betula dahurica (a species of birch). Warm temperate zone species such as the Juniperus chinensis (Chinese juniper), Abies holophylla (needle fir) and Pinus densiflora (Japanese red pine) can also be found here.
The northern temperate forest subzone sits north of the central subzone and extends as far as the borders with China and Russia. Major deciduous broadleaf species of this area include Tilia amurensis (Amur tilia), Tilia ovalis (Manchurian tilia), Prunus maackii (Manchurian cherry), Acer tegmentosum (Manchurian striped maple), Acer komarovii (Komarov maple), Acer ukurunduense (Ukurundu maple), Lonicera chrysanta var. crassipes (a deciduous shrub), Tilia vulgaris (common tilia), Betula schmidtii (Schmidt birch), Quercus mongolica (Mongolian oak), Corylus heterophylla (Asian hazel), Betula costata (Manchurian birch), and Syringa patula (Manchurian lilac), along with needle-leaved evergreens such as the Abies holophylla (needle fir) and Pinus koraiensis (Korean pine), and including as well deciduous conifers such as the Larix olgensis (Olgan larch).
(3) Mixed forest zone
The mixed forest zone refers to forest containing a mixture of conifers and broadleaved trees. There are many stands of planted forests that exhibit trees of all the same species, but natural forests are generally mixed forests. Generally, to speak of a mixed forest mean sthe percentage of broadleaf and conifer trees does not surpass 75 percent.
The vegetation of the Hamgyeongsanmaek, Taebaeksanmaek, and Sobaeksanmaek Ranges, which together form the spine of the Korean Peninsula, is composed of approximately 60 percent deciduous forest and 30 percent mixed deciduous and conifer forest. Representative trees of the Taebaeksanmaek and Sobaeksanmaek Ranges are the Quercus mongolica (Mongolian oak), Quercus serrata (Bao Li), Acer pseudosieboldianum (Korean maple), Pinus densiflora (Japanese red pine), Fraxinus sieboldiana (Siebold ash), Quercus variabilis (cork oak), Fraxinus rhynchophylla (mountain ash), Pinus koraiensis (Korean pine), Quercus dentate (Japanese emperor oak), and the Acer pictum subspecies Mono (painted maple). In terms of small shrubs, common species include the Rhododendron schlippenbachii (royal azalea), Rhododendron mucronulatum var. mucronulatum (a variety of rhododendron), Lindera obtusiloba (blunt-lobed spice bush), Tripterygium regelii (Regel's threewingnut), Sasa borealis (a species of bamboo), Lespedeza maximowiczii (Maximovich lespedeza), Weigela subsessilis (canary weigela), Symplocos chinensis (Chinese symplocos), Rhus trichocarpa (bristly fruit sumac), and Lespedeza bicolor (shrubby bush clover). And regarding varieties of grasses and flowering plants, one finds Carex humilis var. nana (dwarf ground sedge), Carex lanceolata (a species of carex), Aster scaber (a perennial herb known to Koreans as chamchwi), Ainsliaea acerifolia (a perennial woodland herb), Spodiopogon cotulifer (a species grass), Artemisia Keiskeana (a mugwort), Disporum smilacinum (a flowering perennial), Astilbe chinensis (Chinese astilbe), Atractylodes japonica (Japanese atractylodes), and Melampyrum koreanum (Korean melampyrum).
The mixed forest zone boasts a variety of species that are not only very resistant to climatic disasters, forest fires, and environmental pollution, but play an excellent role in natural conservation. Therefore, many deciduous trees are now being mixed in with what were originally artificial conifer forests to create new mixed deciduous and conifer forests.
(4) Needle-leaved evergreen zone
Needle-leaved evergreen conifer zones can be found in high alpine areas in the south, central and northern parts of the peninsula where the mean annual temperature is 5˚C or below and where the January mean temperature is -12˚C or below. Primary species found in this zone have adapted to the frigid winters and short growing season and include the Abies holophylla (needle fir), Picea jezoensis (Jezo spruce), Abies nephrolepis (Manchurian fir), Picea koraiensis (Korean spruce), Pinus koraiensis (Korean pine), Pinus pumila (Siberian dwarf pine), Thuja koaiensis (Korean thuja), Taxus cuspidate (spreading yew), along with evergreen broadleaves and deciduous coniferous species such as the Larix olgensis (Olgan larch), Larix olgensis var. amurensis (Amur larch), and even deciduous broadleaves such as the Betula costata (Manchurian birch) and Betula platyphylla (Japanese white birch).
(5) Vertical vegetation zones
Vertically, the Korean Peninsula may be divided into zones according to latitude and altitude. From the lowest to highest these are, along with vegetation types appearing: the colline or hilly belt (evergreen broadleaf and deciduous broadleaf forests), the piedmont belt (deciduous broadleaves and mixed forests of deciduous broadleaf and needle-leaved evergreens), subalpine belt (coniferous forest), and alpine belt (shrub and alpine grassland). As one ascends from the alpine meadow zone dense alpine forests make their appearance. In the low mountains of the peninsula’s southern region these forests are a mixture of broadleaf evergreen and deciduous trees. As one climbs in altitude the trees become primarily deciduous broadleaves, while the highest alpine forests are a mixture of evergreen conifers and deciduous broadleaves.
At high altitudes one reaches the forest line or timberline, after which no commercially viable trees will grown. Proceeding higher one reaches the tree line, where growing conditions are so poor that trees cannot grow more than 3–5m in height. In the subalpine belt that stretches from the timberline to the tree line one can find varieties of coniferous evergreens such as the Abies koreana (Korean fir), Picea jezoensis (Jezo spruce), Abies nephrolepis (Manchurian fir), and Pinus densiflora (Japanese red pine), as well as varieties of birch and rhododendron, including royal azalea (Rhododendron schlippenbachii), or what Koreans call cheoljjuk. However, the species of trees found in the subalpine belt will vary somewhat by region.
Above the tree line one reaches the alpine belt, subdivided into alpine shrubland and grassland. In the alpine shrubland are found short woody shrubs and bushes, while above this area sits the alpine grassland. All the vegetation of the alpine zone is short, with roots that burrow deep and are relatively elongated compared to stems and branches. Alpine belt shrubs tend to grow closely to the ground, while plants here have thickened leaves with hairs on their surface to better capture moisture while also providing an advantage against cold temperatures.