The earliest occurrence of the genus of pine tree or Pinus on the Korean Peninsula dates to the Cretaceous; the presence of Pinus spp. on the Peninsula continued throughout the Miocene, Pleistocene, and Holocene to the present day. During the Quaternary, Pinus spp. had a wide distribution and maintained dominance over the Korean Peninsula. Pinus spp. later diversi ed into cold-tolerant and warm-tolerant species. Cold-tol- erant Pinus spp. (haploxylon) with 5 needles occupied the northern and high mountains, but Pi- nus spp. (diploxylon) with 2 needles was common in lowlands and coastal regions.
Since the Holocene, Pinus species exhibiting niche characteristics have been occupying differ- ent habitats and locations, becoming a dominant component of the vegetation. Dominance of Pi- nus spp. may be partially due to anthropogenic disturbances, such as agriculture, fire, and land- use patterns at lowland sites. Boreal Pinus species including dwarf stone pine (Pinus pumila), Korean pine (Pinus koraiensis), Chinese hard pine (Pinus tabulaeformis) migrated into the Korean Peninsula during the Pleistocene glacial epochs, away from the harsh environment of the northeast Asia. Their distribution is currently con ned to the alpine and
subalpine belts of the Korean Peninsula.Black pine (Pinus thunbergii) is found mainly in the southern and central-southern coastal areas of Korea. Ulleungdo white pine (Pinus parvi ora) oc- curs in isolation in Ulleungdo and some Japanese islands. Species like black pine (Pinus thunbergii) with larger, winged seeds and often dispersed by wind have wider distributional ranges than species without winged seeds, such as dwarf stone pine (Pinus pumila) and Korean pine (Pinus koraien- sis) that are dispersed by birds and rodents. These species have narrow distribution ranges around the montane and high mountain areas. Species with
disjunctive distributions, such as dwarf stone pine (Pinus pumila) in the alpine and subalpine belts of northern and central Korea, Korean pine (Pinus koraiensis) in mountainous areas, and Ulleungdo white pine (Pinus parviflora) in Ulleungdo are more vulnerable to climate change such as global warming than other Pinus spp..
Korean red pine (Pinus densiflora) and black pine (Pinus thunberigii) in lowland and coastal areas are under the influence of deforestation, over development, and insect outbreak.