Information on Rainforests in Southeast Asia Photo: Rainforests dot the landscape all over Southeast Asia, in mainland countries and on Pacific islands. If you want to experience the splendor southeastern asian rainforests a Southeast Asian jungle, you better go fast, while they still exist. Rainforests are diverse ecosystems southeastern asian rainforests evergreen trees and ground vegetation. Rainforests receive high levels of rainfall and typically exist in areas with warm or moderate temperatures. In late s, Khmer Rouge fighters took refuge in the rainforest after losing power to Vietnamese forces.