Oct. 9 (Bloomberg) -- The Indonesian island of Sumatra, the only place on Earth where tigers, elephants, rhinos and orangutans co-exist, agreed to protect its remaining forests after more than 20 years of intense logging.

The agreement with the World Wildlife Fund is the first on the world's sixth-largest island to curb deforestation, Hermien Roosita, Indonesia's deputy minister of environment, announced at an International Union for the Conservation of Nature meeting.

Sumatra, with 45 million residents, has lost almost half of its rain forest since 1985 to make way for palm oil and pulpwood plantations, according to the WWF. Deforestation in Riau Province has resulted in an 84 percent decline in the elephant population and a 70 percent drop of Sumatran tigers, the group said.

Implementing the new forest preservation policy will require coordination between Sumatra's 10 provinces, which have endorsed the plan, and various Indonesian ministries on an 1,100-mile-long (1,790 kilometers) island that has more than 200 mammal species and 580 bird species, officials said.

``There are a lot of challenges in the future to ensure successful implementation of the commitment,'' Noor Hidayat, director of conservation areas at the Indonesian Ministry of Forestry, said in a statement at the IUCN meeting in Barcelona.

About 13 percent of Sumatra's remaining forests are peat forests, a major source of carbon-dioxide emissions when cleared, according to the IUCN. Cutting down Sumatran rain forest over the past 25 years has generated the equivalent of 58 percent of Australia's annual emissions, the WWF said in February.

To contact the reporter on this story: Adam Satariano in San Francisco at asatariano1@bloomberg.net

Last Updated: October 9, 2008 14:25 EDT