An oak is a tree or shrub in the genus Quercus of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably Lithocarpus, as well as in those of unrelated species such as Grevillea robusta and the Casuarinaceae (she-oaks). The genus Quercus is native to the Northern Hemisphere, and includes deciduous and evergreen species extending from cool temperate to tropical latitudes in the Americas, Asia, Europe, and North Africa. North America has the largest number of oak species, with approximately 160 species in Mexico of which 109 are endemic and about 90 in the United States. The second greatest area of oak diversity is China, with approximately 100 species.
The Fagaceae are a family of flowering plants that includes beeches, chestnuts and oaks, and comprises eight genera with about 927 species. Fagaceae in temperate regions are mostly deciduous, whereas in the tropics, many species occur as evergreen trees and shrubs. They are characterized by alternate simple leaves with pinnate venation, unisexual flowers in the form of catkins, and fruit in the form of cup-like (cupule) nuts. Their leaves are often lobed and both petioles and stipules are generally present. Their fruits lack endosperm and lie in a scaly or spiny husk that may or may not enclose the entire nut, which may consist of one to seven seeds. In the oaks, genus Quercus, the fruit is a non-valved nut called an acorn. The husk of the acorn in most oaks only forms a cup in which the nut sits. Other members of the family have fully enclosed nuts. Fagaceae is one of the most ecologically important woody plant families in the Northern Hemisphere, as oaks form the backbone of temperate forest in North America, Europe, and Asia, and are one of the most significant sources of wildlife food.
Quercus petraea, commonly known as the sessile oak, Cornish oak, Irish Oak or durmast oak, is a species of oak tree native to most of Europe and into Anatolia and Iran. The sessile oak is the national tree of Ireland, and an unofficial emblem in Wales and Cornwall.
The Qinling or Qin Mountains, formerly known as the Nanshan, are a major east–west mountain range in southern Shaanxi Province, China. The mountains mark the divide between the drainage basins of the Yangtze and Yellow River systems, providing a natural boundary between North and South China and support a huge variety of plant and wildlife, some of which is found nowhere else on earth.
Lajia is a Bronze Age archaeological site in the upper reaches of the Yellow River, on the border between the Chinese provinces of Gansu and Qinghai. As at other sites of the Qijia culture, the people of Lajia had an agricultural economy based primarily on millet cultivation and sheep herding. They also kept pigs for use in ritual activities, including making oracle bones, and experimented with a high temperature-fired pottery described as proto-porcelain. The world's oldest known noodles were discovered at the site in 2005.
Quercus dentata, also called Japanese emperor oak or daimyo oak is a species of oak native to East Asia. The name of the tree is often translated as "sweet oak" in English to distinguish it from Western varieties. It is placed in section Quercus.
The Appalachian mixed mesophytic forests is an ecoregion of the temperate broadleaf and mixed forests biome, as defined by the World Wildlife Fund. It consists of mesophytic plants west of the Appalachian Mountains in the Southeastern United States.
Quercus variabilis, the Chinese cork oak, is a species of oak in the section Quercus sect. Cerris, native to a wide area of eastern Asia in southern, central, and eastern China, Taiwan, Japan, and Korea.
Brenneria is a genus of Pectobacteriaceae, containing mostly pathogens of woody plants. This genus is named after the microbiologist Don J. Brenner.
The geology of China consists of three Precambrian cratons surrounded by a number of orogenic belts. The modern tectonic environment is dominated by the continued collision of India with the rest of Asia starting 40–50 million years ago. This has formed the Himalaya and continues to deform most of China. China has vast mineral reserves, a significant earthquake risk in its western regions and rare isolated active volcanoes throughout the country.
Guo Zhengtang is a Chinese geologist specialized in the Cenozoic.
Quercus sagrana, also spelt Quercus sagraeana, the Cuban oak, is a medium-sized evergreen tree native to western Cuba in the Cuban pine forests ecoregion. It is the only oak native to the Caribbean.
Quercus phillyreoides is a species of flowering plant in the genus Quercus, placed in subgenus Cerris and section Ilex. It is evergreen, withstands frost and can be grown in hardiness zone 7. It is native to southern China, the Ryukyu Islands, and Japan, and has been introduced to Korea.
Quercus rex is an Asian species of tree in the family Fagaceae. It has been found in the seasonal tropical forests of northern Indochina, northeastern India, and also in the province of Yunnan in southwestern China. It is placed in subgenus Cerris, section Cyclobalanopsis.
Quercus langbianensis is an uncommon oak tree species in the family Fagaceae. It is placed in subgenus Cerris, section Cyclobalanopsis, the ring-cupped oaks. These differ from other Quercus groups in that they have acorns with distinctive cups: usually with substantial rings, made-up of scales that have grown together. This species can be found in sub-tropical and tropical seasonal forests of Cambodia, China and Vietnam.
Cathaica fasciola is a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Camaenidae.
Zhang Dongju is a Chinese archeologist and an associate professor at the College of Earth and Environmental Sciences of Lanzhou University. Zhang's research determined that the Xiahe mandible found in the Baishiya Karst Cave on the Tibetan Plateau shared DNA with fossilized remains found in the Denisova Cave in Siberia. This moved to 120,000 years earlier the dates of earliest proven hominin activities in the Tibetan Plateau, and revealed for the first time that the Denisovan hominins had spread throughout Asia rather than being located only near the Denisova Cave. Zhang's work is considered likely to prompt reconsideration of other fossil remains using ancient protein analysis. Discover, Science News, and Nova all named the discovery to their lists of top science stories of 2019.
Quercus chenii is a species of oak native to southeast China. It is in subgenus Cerris, section Cerris. A tree reaching 30 metres in height, it grows from sea level to about 600 m (2,000 ft) in elevation, and can form pure stands. Some authorities feel that it could be a synonym of Quercus acutissima.
The Chinese Loess Plateau, or simply the Loess Plateau, is a plateau in north-central China formed of loess, a clastic silt-like sediment formed by the accumulation of wind-blown dust. It is located southeast of the Gobi Desert and is surrounded by the Yellow River. It includes parts of the Chinese provinces of Gansu, Shaanxi and Shanxi. The depositional setting of the Chinese Loess Plateau was shaped by the tectonic movement in the Neogene period, after which strong southeast winds caused by the East Asian Monsoon transported sediment to the plateau during the Quaternary period. The three main morphological types in the Loess Plateau are loess platforms, ridges and hills, formed by the deposition and erosion of loess. Most of the loess comes from the Gobi Desert and other nearby deserts. The sediments were transported to the Loess Plateau during interglacial periods by southeasterly prevailing winds and winter monsoon winds. After the deposition of sediments on the plateau, they were gradually compacted to form loess under the arid climate.
