Thailand's 514,000 square kilometers lie in the middle of mainland Southeast Asia. The nation's axial position influenced many aspects of Thailand's society and culture. The earliest speakers of the Tai language migrated from what is now China, following rivers into northern Thailand and southward to the Mae Nam (river) Chao Phraya Valley. The fertile floodplain and tropical monsoon climate, ideally suited to wet-rice (thamna) cultivation, attracted settlers to this central area rather than to the marginal uplands and mountains of the northern region or the Khorat Plateau to the northeast. By the twelfth century, a number of loosely connected rice-growing and trading states flourished in the upper Chao Phraya Valley. Starting in the middle of the fourteenth century, these central chiefdoms gradually came under the control of the kingdom of Ayutthaya at the southern extremity of the floodplain. Successive capitals, built at various points along the river, became centers of great Thai kingdoms based on rice cultivation and foreign commerce. Unlike the neighboring Khmer and Burmese, the Thai continued to look outward across the Gulf of Thailand and the Andaman Sea toward foreign ports of trade. When European imperialism brought a new phase in Southeast Asian commerce in the late 1800s, Thailand (known then as Siam) was able to maintain its independence as a buffer zone between British-controlled Burma to the west and French-dominated Indochina to the east.
Thailand in the late 1980s shared boundaries with Burma, Malaysia, Laos, and Cambodia. Although neither China nor Vietnam bordered Thailand, the territory of both countries came within 100 kilometers of Thai territory. Many parts of Thailand's boundaries followed natural features, such as the Mekong River. Most borders had been stabilized and demarcated in the late nineteenth and early twentieth centuries in accordance with treaties forced on Thailand and its neighbors by Britain and France. In some areas, however, exact boundaries, especially along Thailand's eastern borders with Laos and Cambodia, were still in dispute in the late 1980s.
Disputes with Cambodia after 1950 arose in part from ill-defined boundaries; the most notable case was a dispute over the Preah Vihear Temple area submitted to the International Court of Justice, which ruled in favor of Cambodia in 1962. During the years that the Cambodian capital, Phnom Penh, was controlled by the Khmer Rouge regime of Pol Pot (1975-79), the border disputes continued. In the early 1980s, the People's Republic of Kampuchea and its mentor, Vietnam, made an issue of boundaries in Prachin Buri Province in eastern Thailand. In contrast to these incidents, which attracted international attention, boundary disputes with Malaysia and Burma were usually handled more cooperatively. Continuing mineral exploration and fishing in the Gulf of Thailand, however, were sources of potential conflict with both neighbors. Adding to general border tensions were the activities of communist-led insurgents, whose operations had been of paramount concern to the Thai government and its security forces for several decades. The problem of communist insurgency was compounded by the activity of what the Thai government labeled "antistate elements." Often the real source of border problems was ordinary criminals or local merchants involved in illegal mining, logging, smuggling, and narcotics production and trade.
<"36.htm">Topography and Drainage
<"37.htm">Regions
<"38.htm">Climate
The most conspicuous features of Thailand's terrain are high mountains, a central plain, and an upland plateau. Mountains cover much of northern Thailand and extend along the Burmese border down through the Malay Peninsula. The central plain is a lowland area drained by the Chao Phraya and its tributaries, the country's principal river system, which feeds into the delta at the head of the Bight of Bangkok. The Chao Phraya system drains about one-third of the nation's territory. In the northeastern part of the country the Khorat Plateau, a region of gently rolling low hills and shallow lakes, drains into the Mekong River through the Mae Nam Mun. The Mekong system empties into the South China Sea and includes a series of canals and dams.
Together, the Chao Phraya and Mekong systems sustain Thailand's agricultural economy by supporting wet-rice cultivation and providing waterways for the transport of goods and people. In contrast, the distinguishing natural features of peninsular Thailand are long coastlines, offshore islands, and diminishing mangrove swamps.
Landforms and drainage divide the country more or less into four natural regions--the North, the Northeast, the Center, and the South. Although Bangkok geographically is part of the central plain, as the capital and largest city this metropolitan area may be considered in other respects a separate region. Each of the four geographical regions differs from the others in population, basic resources, natural features, and level of social and economic development. The diversity of the regions is in fact the most pronounced attribute of Thailand's physical setting.
During the winter months, in the mountainous North the temperature is cool enough for the cultivation of fruits such as lychees and strawberries. These high mountains are incised by steep river valleys and upland areas that border the central plain. A series of rivers, including the Nan, Ping, Wang, and Yom, unite in the lowlands to form the Chao Phraya watershed. Traditionally, these natural features made possible several different types of agriculture, including wet-rice farming in the valleys and shifting cultivation in the uplands. The forested mountains also promoted a spirit of regional independence. Forests, including stands of teak and other economically useful hardwoods that once dominated the North and parts of the Northeast, had diminished by the 1980s to 13 million hectares. In 1961 they covered 56 percent of the country, but by the mid-1980s forestland had been reduced to less than 30 percent of Thailand's total area.
The Northeast, with its poor soils, is not favored agriculturally. The region consists mainly of the dry Khorat Plateau and a few low hills. The short monsoon season brings heavy flooding in the river valleys. Unlike the more fertile areas of Thailand, the Northeast has a long dry season, and much of the land is covered by sparse grasses. Mountains ring the plateau on the west and the south, and the Mekong delineates much of the eastern rim.
The "heartland" of the Central Thai, the Center is a natural self-contained basin often termed "the rice bowl of Asia." The complex irrigation system developed for wet-rice agriculture in this region provided the necessary economic support to sustain the development of the Thai state from the thirteenth-century kingdom of Sukhothai to contemporary Bangkok. Here the rather flat unchanging landscape facilitated inland water and road transport. The fertile area was able to sustain a dense population, 422 persons per square kilometer in 1987, compared with an average of 98 for the country as a whole. The terrain of the region is dominated by the Chao Phraya and its tributaries and by the cultivated paddy fields. Metropolitan Bangkok, the focal point of trade, transport, and industrial activity, is situated on the southern edge of the region at the head of the Gulf of Thailand and includes part of the delta of the Chao Phraya system.
The South, a narrow peninsula, is distinctive in climate, terrain, and resources. Its economy is based on rice cultivation for subsistence and rubber production for industry. Other sources of income include coconut plantations, tin mining, and tourism, which is particularly lucrative on Phuket Island. Rolling and mountainous terrain and the absence of large rivers are conspicuous features of the South. North-south mountain barriers and impenetrable tropical forest caused the early isolation and separate political development of this region. International access through the Andaman Sea and the Gulf of Thailand made the South a crossroads for both Theravada Buddhism, centered at Nakhon Si Thammarat, and Islam, especially in the former sultanate of Pattani on the border with Malaysia.
Thailand's regions are further divided into a total of seventy-three provinces. The country's provinces have the same names as their respective capitals.
Thailand has a tropical monsoon climate; temperatures normally range from an average annual high of 38° C to a low of 19° C. Southwest monsoons that arrive between May and July (except in the South) signal the advent of the rainy season (ridu fon), which lasts into October. November and December mark the onset of the dry season. Temperatures begin to climb in January, and a hot sun parches the landscape. The dry season is shortest in the South because of the proximity of the sea to all parts of the Malay Peninsula. With only minor exceptions, every area of the country receives adequate rainfall, but the duration of the rainy season and the amount of rain vary substantially from region to region and with altitude. The Northeast experiences a long dry season, and its red, porous (laterite) soils retain water poorly, which limits their agricultural potential.