Geography
The continent of Asia is the largest landmass in the world, with a total area of 46.65 million km² as here circumscribed, including European Russia, Japan and smaller satellite islands such as Sri Lanka, Hainan, Taiwan and Sakhalin. Europe is in terms of physical geography a part of this con- tinent (Eurasia) but is treated in a separate chapter in this Atlas. The Malay Archipelago, usually (partly) included in area calculations for the Asian continent but a distant archipelago, is also treated in a separate chapter Malesia. Asia, like Europe, is thus a more or less artificial concept, unlike the other five continents. Geographically it is more diverse than any of these due to its vast extent across all climate zones and its complicated topography. Mainland Asia extends over ca. 77° of latitude and ca. 195° of longitude or around 8600 km N to S and 9700 km E to W. In the far N Russia borders on the Arctic Ocean and arctic desert and tundra merges to the S with the greatest expanse of mostly coniferous taiga forest in the world. This region is further charac- terized by great lowland rivers and generally low, old mountain ranges, both with a mostly S-N orientation, but in European Russia the rivers run southwards. To the E Siberia is extended by the great Kamchatka Peninsula, one of the most active volcanic regions in the world. Southwards, the taiga merges to steppes in Kazakhstan and Mongolia and to high mountains such as the Caucasus, Tien Shan and Altai, which have a mainly E-W orientation. Inland seas (Caspian, Aral, the latter drying) and great lakes (Balkhash, Baikal) lie in the steppe zone or in the transition between taiga and steppe (Baikal). Great deserts span almost the entire width of Asia at middle latitudes, from the Arabian Desert to the Gobi Desert, with some of the driest and harshest deserts among them (Rub al Khali, Takla Makan). Some of these deserts are mountainous (Zagros Mountains, Plateau of Iran) or mountains surround the desert entirely (Takla Makan) and rivers running from them do not drain to the ocean. In the S-central part of the continent rises the Tibetan Plateau, with an area of 2.5 million km² the largest expanse of extremely high country in the world with an average altitude of >4500 m. The Kunlun Range borders it in the N but its most remarkable edge is in the S, formed by the Karakoram–Himalayas with 14 summits over 8000 m tall, culminating in 8848 m at Mt. Everest (Chomolungma). These mountains are flanked in the W by the Hindu Kush and in the E by a series of high mountain ranges trending NW-SE, interspersed by long rivers that have their sources on the Tibetan Plateau. The subcontinent of India, forming an extension of Asia into the Indian Ocean, lies to the S of these great mountains and its drift into the Asian Plate in the early Palaeogene and subsequent pressures have warped them up to their great heights. The subcontinent lies mostly in the tropics and is one of the most densely populated regions of the world. The Deccan Traps, a volcanic plateau of great extent, the Western Ghats and the deltas of the Indus and Ganges Rivers are its main topographical features. Eastern Asia has a complicated topography. From the Manchurian Plain in the N to Hainan Island in the S, this part of China reaches from boreal forest to tropical rainforest. Numerous mountain ranges, many trending N-S, alternate with broad valleys of major rivers and plains such as the Red Basin and the Great Plain 172 mainland asia and japan of China. In Sichuan/Yunnan the mountains rise to over 7000 m. This E half of China is also the region with the largest human population in the world and, like India, it has been under culti- vation for millennia, profoundly altering the landscape and the vegetation. Lastly, mainland SE Asia (Indochina) is a broad peninsula extended by a narrow one, the Malay Peninsula, which leads the continent to its southernmost point at Cape Piai at 1° 16’ N. Its E margin (Viet Nam) is mountainous, as is much of the Malay Peninsula. The Mekong, originating on the Tibetan Plateau, winds its long way through SE Asia forming the Mekong Delta in the S of Viet Nam. Major islands border the Asian continent in the S and E and of these, the group forming Japan with Honshu the central and largest island, is of special interest for conifer biogeography. Japan is mountainous and largely volcanic, like Kamchatka lying in the ‘Ring of Fire’ around the Pacific Ocean. Strings of smaller islands (Kuril Islands, Ryukyu Islands) of volcanic origin link Kamchatka, Japan and Taiwan, the latter island mountainous but not volcanic. Asia can be divided into regions in many ways but here we try to do so with the distribution of conifers in mind. The diversity of conifers in China (including Taiwan) is such that it merits sepa- rate treatment, even though its land boundaries are mostly not natural. Another obvious choice is to treat the conifers of Japan separately, as these islands have a high level of conifer ende- mism. The Himalayas, including the Hindu Kush and Karakoram Ranges, form a natural region of extremely high mountains with many endemic or near endemic conifer species. Mainland SE Asia (Indochina) merits separate treatment for the same reason, with mostly distinct conifer distributions. Elsewhere, regionalisation becomes more diffuse for conifers and the regional divi- sions made here are somewhat arbitrary for several species. Their outlines are, where necessary, explained at the beginning of these chapter sections. The conifers in this chapter are mapped and discussed within the following regions and in that order: Western Asia, Central Asia and Siberia, Himalayas, China and Taiwan, Indochina, Mainland Asia Far East, Japan. Within these regions the taxa are presented in a linear sequence reflecting phylogenetic rela- tionships, following Christenhusz et al. (2011). Statistics are given for China and Taiwan and for Japan, the two regions with greatest conifer diversity.
Conifers in Mainland Asia and Japan
Families Genera Species Species + infra Countries with Area of occupancy Endemic taxa conifers in km² 6/8 36/70 202/615 283/794 39/45 107,925/46,648,350 256
Numbers after ‘/’ are global or continent totals.
Mainland Asia and Japan exhibit high levels of diversity in conifers with six out of eight families, just over half of all genera and nearly a third of the world’s species present. Conifers occur in the wild in almost all countries, the exceptions are Kuwait, Bahrain, Qatar, the United Arab Emirates, Sri Lanka and the Maldives. In many Asian species infra-specific taxa are recognized. This takes the total of taxa below the rank of genus to 283 or 35.6%, more than a third of the world’s total. Of these 256 or 90% are endemic to the region. This is to be expected for such a vast area, with only a few species overlapping with Europe, one species also in Africa ( Juniperus procera) and some more jointly in Malesia. Conifer species are very unevenly distributed across the continent (map MAJ-1 on p. 173), with regions of high concentration contrasting with those poor in species or even devoid of conifers. The map, it must be emphasized once more, shows the distribution of species, not of trees; if it did the latter the boreal north of the continent would be filled with dots. There are not enough herbarium specimen data to fill Siberia more densely to reflect the taiga forest, which is poor in species numbers. At lower latitudes (from 45° N) the map is more accurate. Conifer species are concentrated in Anatolia, W Syria and Lebanon, in the Caucasus and