The park suffers heavy encroachment from illegal loggers and illegal settlers who clear the park for crops and palm oil plantations, as well as village sites. Already, 28,600 hectares, or about a third of the park, has been deforested. In November 2009, WWF announced that the park had finally been expanded by 44,492 hectares but encroachment still remains a serious problem.
According to a WWF report published in June 2013, oil palm plantations cover 36,353 ha of the Tesso Nilo forest complex, with two business groups (Asian Agri and Wilmar Groups) being involved in the trade of the oil palm fruit illegally grown inside the national park. Furthermore, 50 mills operating around the Tesso Nilo forest complex were identified.
During drought periods, the forest is susceptible to wildfires. In the October 2006 fires, 1 km2 of the park was burnt. According to 2009 WWF survey, the population of Sumatran elephants had reached 200 in the park, and around 350 elephant in Riau Province.
Elephant conservation centre
The Belgian government committed to provide 200,000 euros in assistance for the construction of a Sumatran elephant conservation centre in the Tesso Nilo National Park, with the first quarter to be disbursed in 2011. The project will fund the relocation of dozens of tame elephants from Minas in Siak district, to Tesso Nilo. The relocation was justified by the loss of habitat in Minas due to oil palm plantations and oil mining.
In 2012, the elephant population in the park is estimated 120 to 150 elephants through samples of elephant dropping. For three months, starting late of June, Deoxyribonucleic acid (DNA) of elephants’ faeces are being conducted to get the actual number of elephants.