Around 1922 some people from Ban Tha Dan and Ban Tha Chai villages in Nakhon Nayok Province built a settlement within the forest in the Sankamphaeng mountains. Up to 30 households cultivated the land. The area was formally recognized by the government and classified as Tambon Khao Yai within Pak Phli District. However, due to its remoteness from the authorities it became a refuge for criminals and fugitives. After an attempt to capture the suspects in the area, in 1932 the villagers were relocated into the plains some 30 km away and the tambon status was cancelled. In 1959 the prime minister, Field Marshal Sarit Thanarat, instructed the Ministry of Agriculture and the Ministry of the Interior to create a process whereby national parks could be established. Khao Yai National Park was then established on 18 September 1962, declared by royal proclamation in the Government Gazette as the first national park in Thailand. A major role in its establishment was played by Boonsong Lekakul, one of the 20th century's most famous Thai conservationists. It was named after the defunct tambon, Khao Yai. In 1984 the park was made an ASEAN Heritage Park, and on 14 July 2005 the park, together with other parks in the same range and in the Dong Phaya Yen Mountains further north, was proclaimed a UNESCO World Heritage Site under the name "Dong Phaya Yen–Khao Yai Forest Complex". As the lands adjacent to the national park are becoming increasingly developed into luxury hotels and golf courses, acquiring land for future wildlife conservation efforts is becoming problematic. Homes and residential villas have been built illegally within the limits of the protected area of the forest. Illegal logging is also a problem in the area of the park.
Visitors
According to the Department of National Parks, which manages the park, visitors to Khao Yai have risen from 671,569 in 2008 to more than 1.2 million in FY2016. From October 2015 to September 2016, 471,514 vehicles entered the park. The congestion has led to demands to close the park to private vehicles. During one of its busiest periods, New Year's week from 30 December – 3 January 2016, the park saw 156,574 visitors. They left in excess of 23 tonnes of waste behind.
Climate
Khao Yai National Park has three main seasons, with an annual mean temperature of 23° Celsius, though this varies greatly with the seasons.
Rainy season : Most days have high rates of precipitation. The atmosphere is humid with average temperatures of 27 °C during the day dropping to 13 °C at night. Streams at peak flow.
Cool season : Clear skies, sunny and cool. Average temperatures of 22 °C during the day and 10 °C at night. Good time for hiking.
Hot season : Humid with daytime temperatures of 20–30 °C and 17 °C at night.
Geology
is present towards the eastern end close to the Dângrêk Mountains. Sandstone outcrops exist in the south and north of the park. Shales and schist are also present. In the south, steep slopes made of granite and conglomerates are seen.
Drainage
There are four drainage areas in the park which are vital catchments for four river systems. The Lam Takhong River drains from the central Khao Yai area and runs in a northeasterly direction to the Mekong. The Sai Yai River system drains from the eastern basin, turning sharply into the southern floodplains and on to the Gulf of Thailand. The Nakhon Nayok River system drains from the southwest watershed into Nakhon Nayok Province to the south. The Saraburi Province drainage system drains westward from the far west of Khao Yai.
Fauna
Khao Yai is home to a variety of animals. It is one of the few places in Thailand where wild elephants still survive. They are regularly seen and are a major tourist attraction. Other larger animals include gibbons, pig-tailed macaques, muntjacs and sambar deer. In early-2017 it was announced that 18 tigers, including five males, seven female and six cubs, were filmed by surveillance cameras in the Dong Phaya Yen-Khao Yai world heritage site in June 2016 and February 2017 in a joint effort of the Department of National Parks, the Freeland Foundation, and the Panthera Corporation. The last time that tigers were seen by surveillance cameras in Khao Yai National Park was in 2002.
