Thai highlands

Thai Highlands เขตภูเขา (ประเทศไทย)
Map of the Thai highlands
Thailand	Northern Thailand, and parts of Tak and Sukhothai provinces
Area
• Land	107,000 km2 (41,000 sq mi)
Population
• Estimate (2009)	6,300,000
• Density	58.5/km2 (152/sq mi)
Time zone	UTC+7

Doi Phu Kha area in Nan Province at the eastern end close to the Lao border

Hills in Mae Hong Son Province at the western end of the highlands

Doi Nang Non, the "Mountain of the Sleeping Lady"

The Thai Highlands or Hills of Northern Thailand, Thai: เขตภูเขา (ประเทศไทย), are a mountainous natural region in the north of Thailand. Its mountain ranges are part of the system of hills extending through Laos, Burma and China and linking to the Himalayas, of which they may be considered foothills.

The highlands of the North of Thailand are characterized by a pattern of generally steep hill ranges, intermontane basins and alluvial gorges. Altitudes are generally moderate, little above 2,000 m for the highest summits. There is a wide range of elevations though, with floors ranging between 500 m and as low as 200 m above sea level. Towards the Lao border the divide to the Mekong basin becomes higher with peaks occasionally rising above 1,500 m and streams flowing in narrow steep valleys.^[1]

The climate is typical of tropical mountains with clearly delineated wet and dry seasons. Winter temperatures can be cool with frosts occurring most years at higher elevations, but no snow even on the highest peaks.

The region of the Thai Highlands encompasses the nine administrative provinces of Northern Thailand, based on the six-region system, as well as parts of Tak and Sukhothai provinces.

Some areas of the highlands have very little human habitation.

Geography

Except for the Daen Lao Range (ทิวเขาแดนลาว) at the far northern edge, all ranges in the north of Thailand are roughly aligned from north to south. They are linked to a wide system of ranges in neighboring Burma and Laos that does not have a specific name for the whole, "Thai highlands" being the term generally restricted to the Thai area.^[2] Broadly defined, and based on their geological composition, there are two mountainous subsystems in Northern Thailand:

• In the western part the ranges stretching southwards from the Daen Lao Range, in the southern region of the Shan Hills or Shan Highland, with the two parallel mountain chains of the Thanon Thong Chai Range (เทือกเขาถนนธงชัย). This area has the highest elevations, with Doi Inthanon, the highest point in Thailand, reaching 2,565 metres (8,415 ft). The Dawna Range (ทิวเขาดอยมอนกุจู) forms the western border of Thailand between Mae Hong Son and the Salween River,^[3]
• The remaining mountainous region of parallel ranges that extend into northern Laos includes the Khun Tan Range (ทิวเขาขุนตาน), the Phi Pan Nam Range (ทิวเขาผีปันน้ำ), the Phlueng Range (ทิวเขาพลึง) as well as the western part of the Luang Prabang Range (ทิวเขาหลวงพระบาง).^[4]

A great part of the highland area is drained by rivers Ping, Wang, Yom and Nan, all tributaries of the Chao Phraya River flowing in a roughly southern direction. The ranges separating the main rivers are generally steep, high and continuous. Towards the east, as well as in the Wang and Yom drainage basins, they are lower. The Pai River in the northwest flows westwards into the Salween and the northeastern part is drained by rivers of the Mekong basin, like the Kok and Ing.

Geology

Geologically in the southern subranges of the Shan Hills layers of alluvium are superimposed on hard rock. The ranges closer to Laos consist of Permo-Carboniferous limestone, which makes for a more jagged and steep relief, despite the more moderate height.^[5]

Environment and Human impact

Akha hut in the hills near Chiang Rai

The natural environment of the hills used to be dense montane rain forest. Swidden agricultural practices have much reduced the pristine old-growth forest areas which have been replaced by secondary forest.^[6]

For centuries the Thai highlands have been inhabited with hill tribes mostly from Chinese or Tibeto-Burman descent, such as the Akha, Yao, Lahu, Khmu, Hmong and Lisu.^[7] These human groups immigrated into this relatively empty region fleeing persecution or harsh central rule in their respective environments, as well as seeking new land for their shifting agricultural productions system. For the past decades these groups have been undergoing a process of integration into the Thai mainstream.

Owing to the unrest in Burma, some refugee camps have been established for the cross-border refugees in the Thai highlands.^[8] Certain Kayah and Karen communities, like the 'Long-necked Karen', are regularly visited by organized tourist groups.^[9]

At higher altitudes, above about 1,000m, one of the main crops was opium until the 1990s, when the combined effects of development became evident - from the construction of roads into the remote area, increasingly efficient policing, and opium replacement programs.^[10]

Yearly wildfires are started on purpose by local farmers during the dry season in different areas of Northern Thailand. Often speculators also hire people to set forests on fire in order to claim land title deeds for the areas that have become "degraded forest".^[11] The smoke produced by these fires is the main cause of the intense seasonal air pollution in the Thai highlands, also known as the "northern haze".^[12] Fires also contribute to the floods in the country by completely denuding the undergrowth of the woods^[13] and the dry forest soil leads to lower water intake for the trees to extract when the rains arrive.^[14]

Presently large tracts of the mountains are covered with a mixed vegetation resulting from the capacity of the efficient shifting agricultural system being exceeded. As a result large areas end up becoming dominated by Imperata cylindrica grass, which is used throughout Thailand as roofing material. Cattle can graze on the grass to an extent, as agricultural science research in the 1970s defined.^[15] The longer term environmental care of the region is associated with forestry and in the lower reaches, perennial fruit like peaches and other trees.^[16] Also some projects for the restoration of forest cover have been undertaken in ecologically degraded areas.^[17]

Doi Phu Chi Fa, Amphoe Wiang Kaen, Chiang Rai province.

See also

• Doi Inthanon, the highest mountain in Thailand
• Doi Nang Non, a karstic formation in Chiang Rai province
• Golden Triangle (Southeast Asia)
• Deforestation in Thailand
• Tribal Museum in Chiang Mai
• Western Forest Complex
• Southeast Asian Massif

References

External links

Wikimedia Commons has media related to Thai highlands.

• Opium, Power, People: Anthropological Understandings of an Opium Interdiction Project in Thailand
• Dubious Development Concepts in the Thai Highlands: The Chao Khao in Transition
• "Northern Thailand-Laos moist deciduous forests". Terrestrial Ecoregions. World Wildlife Fund. 
• Cultural Landscape of the northern Region of Thailand (ภาคเหนือ)
• Golden Triangle and beyond
• Speciation and Radiation in a River
• Thailand Travel Destinations - Chiang Mai
• Premier orders urgent action to tackle haze in North

Coordinates: 18°30′00″N 98°30′00″E / 18.50000°N 98.50000°E / 18.50000; 98.50000