The Thung Yai – Huai Kha Khaeng Wildlife Sanctuary lies about 350 kilometres north-west of Bangkok, adjacent to the Burmese border. The western part of the sanctuary is known as Thung Yai Naresuan, the eastern part western part of the sanctuary is known as Thung yai Naresuan,the eastern part as Huai Kha Khaeng. The sanctuary area encompasses two important river systems, the Upper Khwae Yai (sometimes called the Mae Klong) and the Huai Kha Khaeng.

One Life and a World Heritage Site

These protected forests are most valuable and important for conservation in the form of wildlife sanctuaries in order to maintain a natural environment that is rich in the biodiversity of forest ecosystem, flora and fauna. These protected forests can guarantee the survival of wildlife animals and protect them from the considerable threats of hunting,illegal logging in some areas home to certain species, and unhealthy development that is not based on basic conservation of the ecosystem.

               In the early hours of 1 September 1990 the sound of a gunshot was heard in a house where Mr. Sueb was living in Huai Kha Khaeng Wildlife Sanctuary. He had decided to end his Life by his own hand.
               His death caused an emotional impact on nature lovers and social justice seekers as well as raising environmental awareness in society. Since then Mr.Sueb has been recognised not only as a forestry official but also as the figurehead for environmental conservation groups in Thailand.
               A few months after Mr.Sueb death, UNESCO inscribed the Thung Yai- Huai Kha Khaeng Wildlife Sanctuaries on the World Heritage List. Finally, his lifelong dream had come true, but at the expense of his own life.

The Biodiversity Hub of the Tropical Forest

               Thung Yai-Huai Kha Khaeng Wildlife Sanctuaries are located in the Thanon Thongchai Mountain Range and reach as far away as the Tanaosri Mountian Rang. They are also situated in a monsoon zone. A majority of the area is covered with a chain of steep mountains and diverse geography, ranging from high peaks, cliffs and valleys, to limestone-rich caves. Two significant river, Kwai Yai and Kwai Noi, wind through the nature reserves. Both rivers are tributaries of the Mae Klong River, which runs through Kanchanaburi and Ratchaburi province before flowing into the Gulf of Thailand.
               A lofty mountain range hinders the southwest monsoon, which subsequently makes the rainwater amount on each side of the range markedly different. The western side has abundant rainfall, whereas the majority of the eastern side is a closed area, thereby having poorer rainfall.
               Thanks largely to the diverse geography, the nature reserves are rich in the variety of wildlife animal and plant species. They are also home to almost every kind of forest ecology in Thailand, such as deciduous and evergreen and deciduous dipterocarp forests in mainly attributed to the selection of Thung Yai-Huai Kha Khaeng Wildlife Sanctuaries as World Heritage site. They are tropical forests that are rarely found in the other parts of the world.

               Dry evergreen forest is a ecological community in a monsoon climate, which experiences a dry season for around three to four months a year. That is the reason why some deciduous species mingle with drought-resistant nondeciduous species. The dry evergreen forest grows in the wet area without any forest fires. The area also has deep soil that is suitably able to hold water. The annual rainfall amount to 1,500 millimetres on average and is located up to 950 metres above sea level.
               Deciduous dipterocarp forest is found in the area with poor rainfall, at lower than 1,250 millimetres per year, and experiences a dry season around six months in a year. The area also has shallow soil that can hold moisture for a short time and which has fewer organic substances. Thus, deciduous forest grows in great abundance in this area. Shorea obtuse and S. siamensis are common trees here. It is open forest and the main ground plants are grasses, a food source for herbivores.
               Deciduous dipterocarp forest is found only in five countries in the world, namely Myanmar, Laos, Cambodia, Vietnam and Thailand.

Thung Yai Grassland

               One of the most striking geographical characteristics of Thung Yai-Huai Kha Khaeng Wildlife Sanctuaries is their vast grassland areas. The rarity of such grassland was one of the contributing factors for World Heritage Site selection.
               The grassland in the Thung Yai Naresuan Wildlife Sanctuary grows on low and curvy hills at a height of 800 metres above sea level. Mostly, the topsoil is shallow and dotted with scattered limestone. The area is covered by both large and small grasslands. The total area is around 100 square kilometres. The large grasslands with specific names are Thung Yai, Thung Krating, Thung Ruesri and Thung Mongdong. Among them, Thung Yai grassland is the largest, covering around 10 square kilometers.
               The survival of the grasslands is directly dependent upon forest fires. If there are no forest fires, the grasslands will gradually diminish due to invasion season arrives every year, the grassland in Thung Yai is destroyed by forest tire. After the flames die down, the minerals in leaves and grasses become water-soluble ashes, an absorbent compost that helps plants grow rapidly. Sometimes, the moisture from dew is enough for the grassland's growth despite no rainfall at all.

               The main characteristic of the grassland in Thung Yai Naresuan Wildlife Sanctuary is sometimes called savanna because it does not have only grass but also shrubs and sparely grown large trees. Even though the word 'savanna' is applied to Thung Yai grassland savanna usually calls to mind the African savanna, which is in a half-desert climate and a far cry from the Thung Yai Naresuan Wildlife Sanctuary
               Instead, The Thung Yai Naresuan grassland is in a monsoon climate and grows in a limestone-rich area. The soil is abundant, but the topsoil is shallow and scattered with limestone. More importantly, the grassland is usually found on the line of limestone subsidence that runs northwest -southeast or else runs parallel to Srisawat fault lines.
               A distinct geographical characteristic, it illustrates the outcome of a marvellous geographical development rarely seen in Thailand.

               Given all the rivers in forests nationwide, only rivers in Thung Yai – Huai Kha Khaeng Wildlife Sanctuaries remain in pristine condition and preserve the gallery forest perfectly, especially the reeds growing along the rivers in lower Huai Kha Khaeng Wildlife Sanctuary that stretch further afield.
               In Thailand most of the gallery forests are submerged in reservoirs. Fortunately, the Nam Chone Dam construction project, and some other environmentally menacing ones, have been called off.
               The significance of the gallery forest in Huai Kha Khaeng Wildlife Sanctuary is that it harbours some rarely seen wildlife animals, especially wild water buffalos (Bubalus arnee) and green peafowl (Pavo muticus).
               In 1965 the Royal Forest Department's exploration team and press people were on their way from southern Huai Kha Khaeng to Pong Naisor salt lick when they came across some wild water buffalos. At that time Huai Kha Kaeng had not yet been recognised as a wildlife sanctuary but soon the attractions of the gallery forest and wildlife animals aplenty were publicly shown on what was then Channel 4, proving that Huai Kha Khaeng was pristine.

               In general, green peafowl have a strong instinct to be on their guard against any danger. If not certain an area is safe enough to find food, they do not venture into it. Consequently, the green peafowl is likely to be the first species to face extinction if ever there are activities that may disturb them. This might cause a ripple effect on other species in the natural world as well. It is regrettable that the vast majority of people still lack a knowledge of this fact.

               Thailand is situated at the heart of Southeast Asia. Biogeographically speaking, the country is located in the Oriental, or Sino-Indian, Region, the second-largest region of diverse biodiversity in the world.
               The biogeographical region means the realm of species distribution patterns that are separated from each other by various geographical conditions. Within a biogeographical region living things evolve differently to elsewhere, depending on the geography. The area overlapping or bordering between two biogeographical regions is a perfect spot, where animals and plants exist more diversely than usual.
               The Oriental Region can be divided into five subregions. Thung Yai-Huai Kha Kheang Wildlife Sanctuaries are both where four subregions overlap, i.e.Sundaic, Indo-Burmese, Sino-Himalayan and Indo-Chinese. Thung Yai-Huai Kha Khaeng Wildlife Sanctuaries are gathering places for wildlife animals from the North to the South and from the East to the West. This explains why these nature reserves are a paradise of rich biodiversity, which helped them earn their recognition from the World Heritage Sites committee.
               In Thung Yai-Huai Kha Khaeng Wildlife Sanctuaries, Phayre’s langur (Semnopithecus phayrei), rufous-neched hornbill (Aceros nipalensis) and green cochoa (Cochoa viridis) are found. They are from the Sino-Himalayan subregion and not found in a lower area than in this subregion. Marbled cats (Pardofelis marnorata), which come from India’s Sikkim state, roam the sanctuaries. Fea’s muntjacs (Muntiacus feae) from the Indo-Burmese subregion and silvered langurs (Semnopithecus cristatus) from the Indo-Chinese subregion also enjoy living in these nature reserves. Asian tapirs (Tapirus indicus) from the Sundaic subregion are not seen in areas above Thung Yai-Huai Kha Khaeng Wildlife Sanctuaries.
               All of these wildlife animals are representatives of an abundant biodiversity and make the sanctuaries their home. It is little wonder that protected areas are a melting pot of some of the most valuable plant and animal species in Southeast Asia.

               Even though this world heritage forest is the largest hub of biodiversity in the region, research on wild species in the forest is conducted in order to gain useful information on wildlife management for the future. Hence, Thung Yai-Huai Kha Khaeng Wildlife Sanctuaries are valuable nature reserves for future research on the flora and fauna. Among targeted wildlife animals the tiger (Panthera tigris) is the focus of attention at the moment.

The World Heritage for Conservation of Rare and near-Extinct Wildlife

               One of the distinctive characteristics of Thung Yai – Huai Kha Khaeng Wildlife Sanctuaries that meets the selection criteria is that the nature reserves are the habitat for near-extinct plant and animal species. They are the largest protected area in Southeast Asia, reaching as far away as the bordering forests of Burma. The abundant forests are a guarantee of survival for diverse plant and animal species.
               The sanctuaries are natural shelters for nearly half the vertebrates found in Thailand. They are home to 153 species of mammal out of 295 found in Thailand and 490 species of bird out of 930 in total. The nature reserves serve as a safe haven to 89 species of reptile out of 313; 41 species of amphibian out of 106; and 188 species of fish out of 500.
               Among them, 21 animal species are recognised by the International Union for the Conservation of Nature and Natural Resources (IUCN) as endangered species and 55 species as threatened species. Many of them are rarely found in the world such as Asian tapirs, marbled cats and Fea’s muntjacs.
               The large-scale protected areas prove a boon to tigers, elephants, gaurs and bantengs as the reserves help them maintain their species in safe havens because they stand a chance to engage in cross-genetic interaction. On the contrary, if wildlife animals are confined to small-scale reserves. They cannot help but have inbreeding amongst themselves, triggering a reduction in genetic diversity, weaker heredity and lower fertility. In a worst-case scenario, they might face extinction despite no hunting from humans.

               Twenty years ago, it was described as Thailand’s “largest remaining wilderness” and one of its “most unexplored regions”. This is still true today because, despite its proximity to Bangkok, Thung Yai – Huai Kha Khaeng Wildlife Sanctuary remains one of the country’s least accessible and least disturbed forest areas. Thung Yai - Huai Kha Khaeng Wildlife Sanctuaries were added to the World Heritage List in 1991 under the following criteria: