Terrain shapes and bedrock
According to COUNTRYAAH, most of Laos is highland, especially in the north where a series of steep ridges with sharp ridges in the northeast – southwest direction meet the country. The peaks reach a height of nearly 2,500 meters above sea level. The border area with Vietnam to the east is also mountainous, with heights of over 2,700 meters above sea level. It is a continuation to the southeast of the Himalayan mountain ranges, here called the Annamitic Mountains, which extend in the northwest – southeast direction.
The main river in Laos is the Mekong. Especially on the eastern side of the river large plains are spreading. Also in the highlands north are important plains, such as the strategically and politically important Krukslätten. The lowlands, which descend from east to west in a number of plateaus, have been built up of alluvial material that the rivers brought down from the mountains. Another fertile area is the Boloven Plateau in the south at an altitude of about 1,200 m above sea level.
The bedrock consists mostly of rocks formed during Mesozoic and Tertiary, in the south especially volcanoes.
Laos has a tropical monsoon climate with rainy season during May – October, when the southwest monsoon gives the country 1,300-2,300 mm of rain. In some places the rainfall is higher, so get e.g. The Boloven Plateau 4 100 mm/year. During the dry season from November to April, the northeast monsoon reigns, and the average temperature is then 16-21 ～ C, except in March and April, when it is about 32 ° C. The humid summer has a temperature of around 27 ° C.
It has been estimated that Laos was previously covered by about 70% of forests, but now these have been severely decimated, among other things. by felling. The evergreen mountain rainforest mainly dominated the northern parts of the country, while lowland rainforest spread on the plain along the Mekong River. Among the characteristic trees in the rainforest should be mentioned a number of high-rise dipterocarpus plants, some of which can reach 60 m in height; These include species such as Dipterocaʹrpus alaʹtus, Anisoʹptera cochinchineʹnse, Parashoʹrea stellaʹta and several Hoʹpea species. In addition, several tree-shaped pea plants, e.g. Pterocaʹrpus macrocaʹrpus and Dalbeʹrgia species.
The more open and slightly more mature and deciduous monsoon forests are found on some soils north and west of the Mekong River. It is in the monsoon forest that there is a stock of teak.
The original forest now accounts for about 30% of the land area, while another 25% is depleted secondary forest. The forestless parts of Laos are dominated by culturally created grasslands, savannas, bush landscapes and bamboo groves.
The fauna is similar to that of other Indochina but is relatively poorer. In the rainforests there are semi-monkeys and monkeys, among others. trigloria, minor trigloria (Nycticeʹbus pygmaeus [-mɛʹ: -]), the rare black-legged costume monkey (Pyʹgathrix niʹgripes) and black gibbon (Hyloʹbates coʹncolor). Both Chinese and Malay ant cones (Maʹnis pentadaʹctyla and M. javaʹnica, respectively) occur. Among the predators are leopard, tree leopard, marble cat (Pardofeʹlis marmoraʹta), collar bear and Malay bear, and among the ungulates mouth jackals, sambar deer and ox banteng, gaur and kouprey (very rare in southern Laos). Indian elephant is rare, and in the south there may be scab paper.
On the rivers are kingfishers, storks, herons and in southern Laos Indian scissors (Ryʹnchops albicoʹllis). In the forests there are bulbils, needle birds, tailors, sunbirds, rhinoceros, beards and chickens, among others. bankivahöna.
Among the herbivores are python norms, cobras, wares and rare in southern Laos siam crocodile (Crocodyʹlus siameʹnsis).
From completely lacking nature-protected areas, Laos deposited 17 so-called national biodiversity reserves in 1993-94, and in recent years another four reserves have been added.