Belum-Temengor is estimated to be as old as 130 million years, making it older than the jungle of the Amazon or Congo.
The area has been identified as an Environmentally Sensitive Area (ESA) Rank 1 under the Malaysian National Physical Plan and recognized by Birdlife International as an Important Bird Area. The Malaysian federal government has labelled the area as a whole as an essential water catchment area and part of Central Forest Spine and plans to protect the forest under the Malaysian National Forestry Act.
Despite that, between the two, only Belum has been gazette as a forest reserve while the rest are open for development. Temenggor in particular is facing considerable deforestation due to logging. Environmental organizations such as Malaysian Nature Society and the World Wildlife Fund have been lobbying both the state and the federal government to gazette the area as a park. The state government of Perak however has resisted the effort citing that logging provides the state with more than RM 30 million in revenue. Nevertheless, the state government gazetted 1,175 square kilometres, part of the Belum forest reserve as state park on May 3 2007.
There is a plan to convert natural forest to plantation forest along the East-West Highway.