The Forest Tradition of Thailand represents one strand of Theravada Buddhism – or “School of the Elders” – the form of Buddhism practiced in many countries of Southeast Asia, such as Sri Lanka, Burma, and Thailand. Known for their strict adherence to the original code of discipline, or Vinaya, laid down by the Buddha, monastics of the Theravada Thai Forest Tradition live simple lives as celibate alms-mendicants. While this wilderness tradition, based around the original mode of practice of the Buddha, has waned in the past, the 20th century saw it revived by Venerable Ajahn Mun, a well-known teacher who practiced in the forests of Thailand and left behind numerous disciples. The tradition is characterized by its adherence to traditional practices such as not handling money, living simply in the forest, and cultivating meditation as a path to enlightenment, or the realization of truth.
For a more in-depth reading, see “The Customs of the Noble Ones”, by Thanissaro Bhikkhu. Access to Insight (Legacy Edition), 7 June 2010, http://www.accesstoinsight.org/lib/authors/thanissaro/customs.html