An ecoregion is an ecologically and geographically defined area, smaller than a bioregion, which in turn is smaller than an ecozone. All three of these are either greater than an ecosystem. Ecoregions cover large areas of land or water, contain characteristic, geographically distinct assemblages of natural communities and species; the biodiversity of flora and ecosystems that characterise an ecoregion tends to be distinct from that of other ecoregions. In theory, biodiversity or conservation ecoregions are large areas of land or water where the probability of encountering different species and communities at any given point remains constant, within an acceptable range of variation. Three caveats are appropriate for all bio-geographic mapping approaches. Firstly, no single bio-geographic framework is optimal for all taxa. Ecoregions reflect the best compromise for as many taxa as possible. Secondly, ecoregion boundaries form abrupt edges. Thirdly, most ecoregions contain habitats. Biogeographic provinces may originate due to various barriers.
Some physical, some climatic and some ocean chemical related. The history of the term is somewhat vague, it had been used in many contexts: forest classifications, biome classifications, biogeographic classifications, etc; the concept of ecoregion of Bailey gives more importance to ecological criteria, while the WWF concept gives more importance to biogeography, that is, distribution of distinct biotas. An ecoregion is a "recurring pattern of ecosystems associated with characteristic combinations of soil and landform that characterise that region". Omernik elaborates on this by defining ecoregions as: "areas within which there is spatial coincidence in characteristics of geographical phenomena associated with differences in the quality and integrity of ecosystems". "Characteristics of geographical phenomena" may include geology, vegetation, hydrology and aquatic fauna, soils, may or may not include the impacts of human activity. There is significant, but not absolute, spatial correlation among these characteristics, making the delineation of ecoregions an imperfect science.
Another complication is that environmental conditions across an ecoregion boundary may change gradually, e.g. the prairie-forest transition in the midwestern United States, making it difficult to identify an exact dividing boundary. Such transition zones are called ecotones. Ecoregions can be categorized using an algorithmic approach or a holistic, "weight-of-evidence" approach where the importance of various factors may vary. An example of the algorithmic approach is Robert Bailey's work for the U. S. Forest Service, which uses a hierarchical classification that first divides land areas into large regions based on climatic factors, subdivides these regions, based first on dominant potential vegetation, by geomorphology and soil characteristics; the weight-of-evidence approach is exemplified by James Omernik's work for the United States Environmental Protection Agency, subsequently adopted for North America by the Commission for Environmental Cooperation. The intended purpose of ecoregion delineation may affect the method used.
For example, the WWF ecoregions were developed to aid in biodiversity conservation planning, place a greater emphasis than the Omernik or Bailey systems on floral and faunal differences between regions. The WWF classification defines an ecoregion as: A large area of land or water that contains a geographically distinct assemblage of natural communities that: Share a large majority of their species and ecological dynamics. According to WWF, the boundaries of an ecoregion approximate the original extent of the natural communities prior to any major recent disruptions or changes. WWF has identified 867 terrestrial ecoregions, 450 freshwater ecoregions across the Earth; the use of the term ecoregion is an outgrowth of a surge of interest in ecosystems and their functioning. In particular, there is awareness of issues relating to spatial scale in the study and management of landscapes, it is recognized that interlinked ecosystems combine to form a whole, "greater than the sum of its parts". There are many attempts to respond to ecosystems in an integrated way to achieve "multi-functional" landscapes, various interest groups from agricultural researchers to conservationists are using the "ecoregion" as a unit of analysis.
The "Global 200" is the list of ecoregions identified by WWF as priorities for conservation. Ecologically based movements like bioregionalism maintain that ecoregions, rather than arbitrarily defined political boundaries, provide a better foundation for the formation and governance of human communities, have proposed ecoregions and watersheds as the basis for bioregional democracy initiatives. Terrestrial ecoregions are land ecoregions, as distinct from marine ecoregions. In this context, terrestrial is used to mean "of land", rather than the more general sense "of Earth". WWF ecologists divide the land surface of the Earth into 8 major ecozones containing 867 smaller terrestrial ecoregions; the WWF effort is a synthesis of
Denmark the Kingdom of Denmark, is a Nordic country and the southernmost of the Scandinavian nations. Denmark lies southwest of Sweden and south of Norway, is bordered to the south by Germany; the Kingdom of Denmark comprises two autonomous constituent countries in the North Atlantic Ocean: the Faroe Islands and Greenland. Denmark proper consists of a peninsula, an archipelago of 443 named islands, with the largest being Zealand and the North Jutlandic Island; the islands are characterised by flat, arable land and sandy coasts, low elevation and a temperate climate. Denmark has a total area of 42,924 km2, land area of 42,394 km2, the total area including Greenland and the Faroe Islands is 2,210,579 km2, a population of 5.8 million. The unified kingdom of Denmark emerged in the 10th century as a proficient seafaring nation in the struggle for control of the Baltic Sea. Denmark and Norway were ruled together under one sovereign ruler in the Kalmar Union, established in 1397 and ending with Swedish secession in 1523.
The areas of Denmark and Norway remained under the same monarch until Denmark -- Norway. Beginning in the 17th century, there were several devastating wars with the Swedish Empire, ending with large cessions of territory to Sweden. After the Napoleonic Wars, Norway was ceded to Sweden, while Denmark kept the Faroe Islands and Iceland. In the 19th century there was a surge of nationalist movements, which were defeated in the 1864 Second Schleswig War. Denmark remained neutral during World War I. In April 1940, a German invasion saw brief military skirmishes while the Danish resistance movement was active from 1943 until the German surrender in May 1945. An industrialised exporter of agricultural produce in the second half of the 19th century, Denmark introduced social and labour-market reforms in the early 20th century that created the basis for the present welfare state model with a developed mixed economy; the Constitution of Denmark was signed on 5 June 1849, ending the absolute monarchy, which had begun in 1660.
It establishes a constitutional monarchy organised as a parliamentary democracy. The government and national parliament are seated in Copenhagen, the nation's capital, largest city, main commercial centre. Denmark exercises hegemonic influence in the Danish Realm, devolving powers to handle internal affairs. Home rule was established in the Faroe Islands in 1948. Denmark negotiated certain opt-outs, it is among the founding members of NATO, the Nordic Council, the OECD, OSCE, the United Nations. Denmark is considered to be one of the most economically and developed countries in the world. Danes enjoy a high standard of living and the country ranks in some metrics of national performance, including education, health care, protection of civil liberties, democratic governance and human development; the country ranks as having the world's highest social mobility, a high level of income equality, is among the countries with the lowest perceived levels of corruption in the world, the eleventh-most developed in the world, has one of the world's highest per capita incomes, one of the world's highest personal income tax rates.
The etymology of the word Denmark, the relationship between Danes and Denmark and the unifying of Denmark as one kingdom, is a subject which attracts debate. This is centered on the prefix "Dan" and whether it refers to the Dani or a historical person Dan and the exact meaning of the -"mark" ending. Most handbooks derive the first part of the word, the name of the people, from a word meaning "flat land", related to German Tenne "threshing floor", English den "cave"; the -mark is believed to mean woodland or borderland, with probable references to the border forests in south Schleswig. The first recorded use of the word Danmark within Denmark itself is found on the two Jelling stones, which are runestones believed to have been erected by Gorm the Old and Harald Bluetooth; the larger stone of the two is popularly cited as Denmark's "baptismal certificate", though both use the word "Denmark", in the form of accusative ᛏᛅᚾᛘᛅᚢᚱᚴ tanmaurk on the large stone, genitive ᛏᛅᚾᛘᛅᚱᚴᛅᚱ "tanmarkar" on the small stone.
The inhabitants of Denmark are there called "Danes", in the accusative. The earliest archaeological findings in Denmark date back to the Eem interglacial period from 130,000–110,000 BC. Denmark has been inhabited since around 12,500 BC and agriculture has been evident since 3900 BC; the Nordic Bronze Age in Denmark was marked by burial mounds, which left an abundance of findings including lurs and the Sun Chariot. During the Pre-Roman Iron Age, native groups began migrating south, the first tribal Danes came to the country between the Pre-Roman and the Germanic Iron Age, in the Roman Iron Age; the Roman provinces maintained trade routes and relations with native tribes in Denmark, Roman coins have been found in Denmark. Evidence of strong Celtic cultural influence dates from this period in Denmark and much of North-West Europe and is among other things reflected in the finding of the Gundestrup cauldron; the tribal Danes came from the east Danish islands and Scania and spoke an early form of North Germanic.
Historians believe that before their arrival, most of Jutland and the nearest islands were settled by tribal J
Nepal the Federal Democratic Republic of Nepal, is a landlocked country in South Asia. It is located in the Himalayas but includes parts of the Indo-Gangetic Plain. With an estimated population of 26.4 million, it is 48th largest country by population and 93rd largest country by area. It borders China in the north and India in the south and west while Bangladesh is located within only 27 km of its southeastern tip and Bhutan is separated from it by the Indian state of Sikkim. Nepal has a diverse geography, including fertile plains, subalpine forested hills, eight of the world's ten tallest mountains, including Mount Everest, the highest point on Earth. Kathmandu is largest city. Nepal is a multiethnic nation with Nepali as the official language; the name "Nepal" is first recorded in texts from the Vedic period of the Indian subcontinent, the era in ancient India when Hinduism was founded, the predominant religion of the country. In the middle of the first millennium BCE, Gautama Buddha, the founder of Buddhism, was born in Lumbini in southern Nepal.
Parts of northern Nepal were intertwined with the culture of Tibet. The centrally located Kathmandu Valley is intertwined with the culture of Indo-Aryans, was the seat of the prosperous Newar confederacy known as Nepal Mandala; the Himalayan branch of the ancient Silk Road was dominated by the valley's traders. The cosmopolitan region developed distinct traditional architecture. By the 18th century, the Gorkha Kingdom achieved the unification of Nepal; the Shah dynasty established the Kingdom of Nepal and formed an alliance with the British Empire, under its Rajput Rana dynasty of premiers. The country was never colonized but served as a buffer state between Imperial China and British India. Parliamentary democracy was introduced in 1951, but was twice suspended by Nepalese monarchs, in 1960 and 2005; the Nepalese Civil War in the 1990s and early 2000s resulted in the proclamation of a secular republic in 2008, ending the world's last Hindu monarchy. The Constitution of Nepal, adopted in 2015, establishes Nepal as a federal secular parliamentary republic divided into seven provinces.
Nepal was admitted to the United Nations in 1955, friendship treaties were signed with India in 1950 and the People's Republic of China in 1960. Nepal hosts the permanent secretariat of the South Asian Association for Regional Cooperation, of which it is a founding member. Nepal is a member of the Non Aligned Movement and the Bay of Bengal Initiative; the military of Nepal is the fifth largest in South Asia. Local legends have it that a Hindu sage named "Ne" established himself in the valley of Kathmandu in prehistoric times, that the word "Nepal" came into existence as the place was protected by the sage "Nemi", it is mentioned in Vedic texts. According to the Skanda Purana, a rishi called. In the Pashupati Purana, he is mentioned as a protector, he is said to have taught there. The name of the country is identical in origin to the name of the Newar people; the terms "Nepāl", "Newār", "Newāl" and "Nepār" are phonetically different forms of the same word, instances of the various forms appear in texts in different times in history.
Nepal is the learned Sanskrit form and Newar is the colloquial Prakrit form. A Sanskrit inscription dated 512 CE found in Tistung, a valley to the west of Kathmandu, contains the phrase "greetings to the Nepals" indicating that the term "Nepal" was used to refer to both the country and the people, it has been suggested that "Nepal" may be a Sanskritization of "Newar", or "Newar" may be a form of "Nepal". According to another explanation, the words "Newar" and "Newari" are vulgarisms arising from the mutation of P to V, L to R. Neolithic tools found in the Kathmandu Valley indicate that people have been living in the Himalayan region for at least eleven thousand years. Nepal is first mentioned in the late Vedic Atharvaveda Pariśiṣṭa as a place exporting blankets, in the post-Vedic Atharvashirsha Upanishad. In Samudragupta's Allahabad Pillar it is mentioned as a border country; the Skanda Purana has a separate chapter, known as "Nepal Mahatmya", with more details. Nepal is mentioned in Hindu texts such as the Narayana Puja.
Legends and ancient texts that mention the region now known as Nepal reach back to the 30th century BC. The Gopal Bansa were one of the earliest inhabitants of Kathmandu valley; the earliest rulers of Nepal were the Kiratas, peoples mentioned in Hindu texts, who ruled Nepal for many centuries. Various sources mention up to 32 Kirati kings. Around 500 BCE, small kingdoms and confederations of clans arose in the southern regions of Nepal. From one of these, the Shakya polity, arose a prince who renounced his status to lead an ascetic life, founded Buddhism, came to be known as Gautama Buddha. By 250 BCE, the southern regions had come under the influence of the Maurya Empire of North India and became a vassal state under the Gupta Empire in the 4th century CE. There is a quite detailed description of the kingdom of Nepal in the account of the renowned Chinese Buddhist pilgrim monk Xuanzang, dating from about 645 CE. Stone inscriptions in the Kathmandu Valley are important sources for the history of Nepal.
The kings of the Lichhavi dynasty have been found to have r
A birch is a thin-leaved deciduous hardwood tree of the genus Betula, in the family Betulaceae, which includes alders and hornbeams. It is related to the beech-oak family Fagaceae; the genus Betula contains 30 to 60 known taxa of which 11 are on the IUCN 2011 Red List of Threatened Species. They are a rather short-lived pioneer species widespread in the Northern Hemisphere in northern areas of temperate climates and in boreal climates. Birch species are small to medium-sized trees or shrubs of northern temperate and boreal climates; the simple leaves are alternate, singly or doubly serrate, feather-veined and stipulate. They appear in pairs, but these pairs are borne on spur-like, two-leaved, lateral branchlets; the fruit is a small samara. They differ from the alders in that the female catkins are not woody and disintegrate at maturity, falling apart to release the seeds, unlike the woody, cone-like female alder catkins; the bark of all birches is characteristically marked with long, horizontal lenticels, separates into thin, papery plates upon the paper birch.
Distinctive colors give the common names gray, black and yellow birch to different species. The buds form early and are full grown by midsummer, all are lateral, no terminal bud is formed; the wood of all the species is close-grained with a satiny texture and capable of taking a fine polish. The flowers are monoecious, opening with or before the leaves and borne once grown these leaves are 3–6 millimetres long on three-flowered clusters in the axils of the scales of drooping or erect catkins or aments. Staminate aments are pendulous, clustered or solitary in the axils of the last leaves of the branch of the year or near the ends of the short lateral branchlets of the year, they remain rigid during the winter. The scales of the staminate aments when mature are broadly ovate, yellow or orange color below the middle, dark chestnut brown at apex; each scale bears two bractlets and three sterile flowers, each flower consisting of a sessile, membranaceous two-lobed, calyx. Each calyx bears four short filaments with one-celled anthers or two filaments divided into two branches, each bearing a half-anther.
Anther cells open longitudinally. The pistillate aments are pendulous, solitary; the pistillate scales are oblong-ovate, three-lobed, pale yellow-green tinged with red, becoming brown at maturity. These scales bear each flower consisting of a naked ovary; the ovary is compressed, two-celled, crowned with two slender styles. Each scale bears a single small, winged nut, oval, with two persistent stigmas at the apex. Betula species are organised into five subgenera. Birches native to Europe and Asia include Betula albosinensis – Chinese red birch Betula alnoides – alder-leaf birch Betula ashburneri – Betula baschkirica – Betula bomiensis – Betula browicziana – Betula calcicola – Betula celtiberica – Betula chichibuensis – Betula chinensis – Chinese dwarf birch Betula coriaceifolia – Betula corylifolia – Betula costata – Betula cylindrostachya – Betula dahurica – Betula delavayi – Betula ermanii – Erman's birch Betula falcata – Betula fargesii – Betula fruticosa – Betula globispica – Betula gmelinii – Betula grossa – Japanese cherry birch Betula gynoterminalis – Betula honanensis – Betula humilis or Betula kamtschatica – Kamchatka birch platyphylla Betula insignis – Betula karagandensis – Betula klokovii – Betula kotulae – Betula litvinovii – Betula luminifera – Betula maximowiczii – monarch birch Betula medwediewii – Caucasian birch Betula megrelica – Betula microphylla – Betula nana – dwarf birch ) Betula pendula – silver birch Betula platyphylla – —Siberian silver birch Betula potamophila – Betula potaninii – Betula psammophila – Betula pubescens – downy birch known as white, European white or hairy birch Betula raddeana – Betula saksaren
The Himalayas, or Himalaya, form a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has many including the highest, Mount Everest; the Himalayas include over fifty mountains exceeding 7,200 m in elevation, including ten of the fourteen 8,000-metre peaks. By contrast, the highest peak outside Asia is 6,961 m tall. Lifted by the subduction of the Indian tectonic plate under the Eurasian Plate, the Himalayan mountain range runs west-northwest to east-southeast in an arc 2,400 km long, its western anchor, Nanga Parbat, lies just south of the northernmost bend of Indus river. Its eastern anchor, Namcha Barwa, is just west of the great bend of the Yarlung Tsangpo River; the Himalayan range is bordered on the northwest by the Hindu Kush ranges. To the north, the chain is separated from the Tibetan Plateau by a 50–60 km wide tectonic valley called the Indus-Tsangpo Suture. Towards the south the arc of the Himalaya is ringed by the low Indo-Gangetic Plain.
The range varies in width from 350 km in the west to 150 km in the east. The Himalayas are distinct from the other great ranges of central Asia, although sometimes the term'Himalaya' is loosely used to include the Karakoram and some of the other ranges; the Himalayas are inhabited by 52.7 million people, are spread across five countries: Nepal, Bhutan and Pakistan. Some of the world's major rivers – the Indus, the Ganges and the Tsangpo-Brahmaputra – rise in the Himalayas, their combined drainage basin is home to 600 million people; the Himalayas have a profound effect on the climate of the region, helping to keep the monsoon rains on the Indian plain and limiting rainfall on the Tibetan plateau. The Himalayas have profoundly shaped the cultures of the Indian subcontinent; the name of the range derives from himá and ā-laya. They are now known as the "Himalaya Mountains" shortened to the "Himalayas", they were described in the singular as the Himalaya. This was previously transcribed Himmaleh, as in Emily Dickinson's poetry and Henry David Thoreau's essays.
The mountains are known as the Himālaya in Nepali and Hindi, the Himalaya or'The Land of Snow' in Tibetan, the Hamaleh Mountain Range in Urdu and the Ximalaya Mountain Range in Chinese. In the middle of the great curve of the Himalayan mountains lie the 8,000 m peaks of Dhaulagiri and Annapurna in Nepal, separated by the Kali Gandaki Gorge; the gorge splits the Himalayas into Western and Eastern sections both ecologically and orographically – the pass at the head of the Kali Gandaki, the Kora La is the lowest point on the ridgeline between Everest and K2. To the east of Annapurna are the 8,000 m peaks of Manaslu and across the border in Tibet, Shishapangma. To the south of these lies Kathmandu, the capital of Nepal and the largest city in the Himalayas. East of the Kathmandu Valley lies valley of the Bhote/Sun Kosi river which rises in Tibet and provides the main overland route between Nepal and China – the Araniko Highway/China National Highway 318. Further east is the Mahalangur Himal with four of the world's six highest mountains, including the highest: Cho Oyu, Everest and Makalu.
The Khumbu region, popular for trekking, is found here on the south-western approaches to Everest. The Arun river drains the northern slopes of these mountains, before turning south and flowing through the range to the east of Makalu. In the far east of Nepal, the Himalayas rise to the Kanchenjunga massif on the border with India, the third highest mountain in the world, the most easterly 8,000 m summit and the highest point of India; the eastern side of Kanchenjunga is in the Indian state of Sikkim. An independent Kingdom, it lies on the main route from India to Lhasa, which passes over the Nathu La pass into Tibet. East of Sikkim lies the ancient Buddhist Kingdom of Bhutan; the highest mountain in Bhutan is Gangkhar Puensum, a strong candidate for the highest unclimbed mountain in the world. The Himalayas here are becoming rugged with forested steep valleys; the Himalayas continue, turning northeast, through the Indian State of Arunachal Pradesh as well as Tibet, before reaching their easterly conclusion in the peak of Namche Barwa, situated in Tibet inside the great bend of the Yarlang Tsangpo river.
On the other side of the Tsangpo, to the east, are the Kangri Garpo mountains. The high mountains to the north of the Tsangpo including Gyala Peri, are sometimes included in the Himalayas. Going west from Dhaulagiri, Western Nepal is somewhat remote and lacks major high mountains, but is home to Rara Lake, the largest lake in Nepal; the Karnali River cuts through the center of the region. Further west, the border with India follows the Sarda River and provides a trade route into China, where on the Tibetan plateau lies the high peak of Gurla Mandhata. Just across Lake Manasarovar from this lies the sacred Mount Kailash, which stands close to the source of the four main rivers of Himalayas and is revered in Hinduism, Sufism and Bonpo. In the newly created Indian state of Uttarkhand, the Himalayas rise again as the Garhwal Himalayas with the high peaks of Nanda Devi and Kamet; the state is an important pilgrimage destination, with
China the People's Republic of China, is a country in East Asia and the world's most populous country, with a population of around 1.404 billion. Covering 9,600,000 square kilometers, it is the third- or fourth-largest country by total area. Governed by the Communist Party of China, the state exercises jurisdiction over 22 provinces, five autonomous regions, four direct-controlled municipalities, the special administrative regions of Hong Kong and Macau. China emerged as one of the world's earliest civilizations, in the fertile basin of the Yellow River in the North China Plain. For millennia, China's political system was based on hereditary monarchies, or dynasties, beginning with the semi-legendary Xia dynasty in 21st century BCE. Since China has expanded, re-unified numerous times. In the 3rd century BCE, the Qin established the first Chinese empire; the succeeding Han dynasty, which ruled from 206 BC until 220 AD, saw some of the most advanced technology at that time, including papermaking and the compass, along with agricultural and medical improvements.
The invention of gunpowder and movable type in the Tang dynasty and Northern Song completed the Four Great Inventions. Tang culture spread in Asia, as the new Silk Route brought traders to as far as Mesopotamia and Horn of Africa. Dynastic rule ended in 1912 with the Xinhai Revolution; the Chinese Civil War resulted in a division of territory in 1949, when the Communist Party of China established the People's Republic of China, a unitary one-party sovereign state on Mainland China, while the Kuomintang-led government retreated to the island of Taiwan. The political status of Taiwan remains disputed. Since the introduction of economic reforms in 1978, China's economy has been one of the world's fastest-growing with annual growth rates above 6 percent. According to the World Bank, China's GDP grew from $150 billion in 1978 to $12.24 trillion by 2017. Since 2010, China has been the world's second-largest economy by nominal GDP and since 2014, the largest economy in the world by purchasing power parity.
China is the world's largest exporter and second-largest importer of goods. China is a recognized nuclear weapons state and has the world's largest standing army and second-largest defense budget; the PRC is a permanent member of the United Nations Security Council as it replaced the ROC in 1971, as well as an active global partner of ASEAN Plus mechanism. China is a leading member of numerous formal and informal multilateral organizations, including the Shanghai Cooperation Organization, WTO, APEC, BRICS, the BCIM, the G20. In recent times, scholars have argued that it will soon be a world superpower, rivaling the United States; the word "China" has been used in English since the 16th century. It is not a word used by the Chinese themselves, it has been traced through Portuguese and Persian back to the Sanskrit word Cīna, used in ancient India."China" appears in Richard Eden's 1555 translation of the 1516 journal of the Portuguese explorer Duarte Barbosa. Barbosa's usage was derived from Persian Chīn, in turn derived from Sanskrit Cīna.
Cīna was first used including the Mahābhārata and the Laws of Manu. In 1655, Martino Martini suggested that the word China is derived from the name of the Qin dynasty. Although this derivation is still given in various sources, it is complicated by the fact that the Sanskrit word appears in pre-Qin literature; the word may have referred to a state such as Yelang. The meaning transferred to China as a whole; the origin of the Sanskrit word is still a matter of debate, according to the Oxford English Dictionary. The official name of the modern state is the "People's Republic of China"; the shorter form is "China" Zhōngguó, from zhōng and guó, a term which developed under the Western Zhou dynasty in reference to its royal demesne. It was applied to the area around Luoyi during the Eastern Zhou and to China's Central Plain before being used as an occasional synonym for the state under the Qing, it was used as a cultural concept to distinguish the Huaxia people from perceived "barbarians". The name Zhongguo is translated as "Middle Kingdom" in English.
Archaeological evidence suggests that early hominids inhabited China between 2.24 million and 250,000 years ago. The hominid fossils of Peking Man, a Homo erectus who used fire, were discovered in a cave at Zhoukoudian near Beijing; the fossilized teeth of Homo sapiens have been discovered in Fuyan Cave in Hunan. Chinese proto-writing existed in Jiahu around 7000 BCE, Damaidi around 6000 BCE, Dadiwan from 5800–5400 BCE, Banpo dating from the 5th millennium BCE; some scholars have suggested. According to Chinese tradition, the first dynasty was the Xia, which emerged around 2100 BCE; the dynasty was considered mythical by historians until scientific excavations found early Bronze Age sites at Erlitou, Henan in 1959. It remains unclear whether these sites are the remains of the Xia dynasty or of another culture from the same period; the succeeding Shang dynasty is the earliest to be confirmed by contemporary records. The Shang ruled the plain of the Yellow River in eastern China from the 17th to the 11th century BCE.
Their oracle bone script
Eucalyptus is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae known as eucalypts. Plants in the genus Eucalyptus have bark, smooth, fibrous or stringy, leaves with oil glands, sepals and petals that are fused to form a "cap" or operculum over the stamens; the fruit is a woody capsule referred to as a "gumnut". Australia is covered by 92,000,000 hectares of eucalypt forest, comprising three quarters of the area covered by native forest. There most are native to Australia. One species, Eucalyptus deglupta, ranges as far north as the Philippines. Of the 15 species found outside Australia, just nine are non-Australian. Species of eucalyptus are cultivated in the tropical and temperate world, including the Americas, Africa, the Mediterranean Basin, the Middle East and the Indian subcontinent. However, the range over which many eucalypts can be planted in the temperate zone is constrained by their limited cold tolerance. On warm days, eucalyptus forests are sometimes shrouded in a smog-like mist of vaporised volatile organic compounds.
Eucalypts vary in habit from shrubs to tall trees. Trees have a single main stem or trunk but many eucalypts are mallees that are multistemmed from ground level and taller than 10 metres. There is no clear distinction between a mallee and a shrub but in eucalypts, a shrub is a mature plant less than 1 metre tall and growing in an extreme environment. E. vernicosa in the Tasmanian highlands, E. yalatensis on the Nullarbor and E. surgens growing on coastal cliffs in Western Australia are examples of eucalypt shrubs. The terms "mallet" and "marlock" are only applied to Western Australian eucalypts. A mallet is a tree with a single thin trunk with a steeply branching habit but lacks both a lignotuber and epicormic buds. E. astringens is an example of a mallet. A marlock is a shrub or small tree with a single, short trunk, that lacks a lignotuber and has spreading, densely leafy branches that reach to the ground. E. platypus is an example of a marlock. Eucalyptus trees, including mallees and marlocks, are single-stemmed and include Eucalyptus regnans, the tallest known flowering plant on Earth.
The term "morrell" is somewhat obscure in origin and appears to apply to trees of the western Australian wheatbelt and goldfields which have a long, straight trunk rough-barked. It is now used for E. longicornis and E. melanoxylon. Tree sizes follow the convention of: Small: to 10 m in height Medium-sized: 10–30 m Tall: 30–60 m Very tall: over 60 m All eucalypts add a layer of bark every year and the outermost layer dies. In about half of the species, the dead bark is shed exposing a new layer of living bark; the dead bark may be shed in ribbons or in small flakes. These species are known as "smooth barks" and include E. sheathiana, E. diversicolor, E. cosmophylla and E. cladocalyx. The remaining species retain the dead bark which accumulates. In some of these species, the fibres in the bark are loosely intertwined or more adherent. In some species the rough bark is infused with gum resin. Many species are ‘half-barks’ or ‘blackbutts’ in which the dead bark is retained in the lower half of the trunks or stems — for example, E. brachycalyx, E. ochrophloia, E. occidentalis — or only in a thick, black accumulation at the base, as in E. clelandii.
In some species in this category, for example E. youngiana and E. viminalis, the rough basal bark is ribbony at the top, where it gives way to the smooth upper stems. The smooth upper bark of the half-barks and that of the smooth-barked trees and mallees can produce remarkable colour and interest, for example E. deglupta. E. Globulus bark cells are able to photosynthesize in the absence of foliage, conferring an "increased capacity to re-fix internal CO2 following partial defoliation"; this allows the tree to grow in less-than-ideal climates, in addition to providing a better chance of recovery from damage sustained to its leaves in an event such as a fire. Different recognised types of bark include: Stringybark — consists of long fibres and can be pulled off in long pieces, it is thick with a spongy texture. Ironbark — is hard and furrowed, it is impregnated with dried kino which gives a dark red or black colour. Tessellated — bark is broken up into many distinct flakes, they can flake off. Box — has short fibres.
Some show tessellation. Ribbon -- is still loosely attached in some places, they can be firmer strips, or twisted curls. Nearly all eucalyptus are evergreen, but some tropical species lose their leaves at the end of the dry season; as in other members of the myrtle family, eucalyptus leaves are covered with oil glands. The copious oils produced are an important feature of the genus. Although mature eucalyptus trees may be towering and leafed, their shade is characteristically patchy because the leaves hang downwards; the leaves on a mature eucalyptus plant are lanceolate, petiolate alternate and waxy or glossy green. In contrast, the leaves of seedlings are opposite and glaucous, but many exceptions to this pattern exist. Many species