The enquiry found that in the dense natural forests of the Bukit Tigapuluh landscape companies affiliated the Asia Pulp & Paper/Sinar Mas Group (APP/SMG) have sought out selective logging concessions.
The companies obtained government licenses to switch the forest status to industrial timber plantation concessions, sometimes under legally questionable circumstances. This allows for clearcutting and planting of commercial plantations, destroying the home of local tigers and other endangered species.
It is also in breach of the company's claims that it doesn't clear high-quality forest.
"Our investigation found that in the last six years, the company in this landscape alone contributed to the loss of about 60,000 hectares of forest without appropriate professional assessments or stakeholder consultation," said Susanto Kurniawan of the environmental conservation group Eyes on the Forest.
"Bukit Tigapuluh is one of very few remaining rainforests in central Sumatra; therefore we urge the Government not to give it away to APP/SMG, who will mercilessly eliminate it and devastate local communities and biodiversity."
Bukit Tigapuluh has about 320,000 hectares of natural forest, and harbors about 30 of the 300 Sumatran tigers which still survive on the island. It has been deemed one of 20 landscapes critical to the long-term survival of tigers by international scientists. In November, Indonesia pledged at the Global Tiger Forum in St. Petersburg, Russia to make it a focal area for tiger conservation.
Approximately 150 elephants and 130 highly endangered Sumatran orangutans also live in the area.
The area is also home to two indigenous forest-dwelling tribes -- the Orang Rimba and Talang Mamak - who are "being driven off their ancestral land by APP and other companies," said Diki Kurniawan from WARSI, an Indonesian community conservation organization. "Many must now beg for rice handouts to survive."
After a $1 billion pledge from Norway, Indonesia announced this year a moratorium starting in 2011 on all new forest and peatland concessions. The moratorium includes Sumatra.
"The Bukit Tigapuluh landscape is a major test of Indonesia's $1 billion climate agreement with the Kingdom of Norway," said Aditya Bayunanda of WWF-Indonesia "We stand ready to help the Government find ways to protect the forest and Indonesia's natural heritage."