Sumatra’s Forests, their Wildlife and the Climate Windows in Time: 1985, 1990, 2000 and 2009

The report documents a severe decline in Sumatra's natural forests, which shrank from 25.3 million hectares in 1985 to 12.8 million hectares by 2008/9. This deforestation, driven largely by oil palm and pulpwood plantations, has resulted in massive CO2 emissions from biomass loss and peatland degradation, particularly in Riau Province. The loss of habitat has led to significant population declines in the Sumatran elephant, orangutan, rhinoceros, and tiger, while 17 of 38 eco-floristic sectors are now categorized as threatened. The authors argue that protecting remaining peatland forests and restoring degraded areas are critical for meeting Indonesia's emission reduction targets.

• Sumatra's natural forest cover decreased from 25.3 million hectares (58% of the mainland) in 1985 to 12.8 million hectares (29%) in 2008/9, with an average annual loss of 542,000 hectares.
• Lowland forests below 150 meters elevation were disproportionately affected, accounting for 81% (10.1 million hectares) of all natural forest loss between 1985 and 2008/9.
• Riau Province experienced the highest deforestation rate on the island; it lost 4.4 million hectares (63%) of its natural forest between 1985 and 2008/9, contributing 35% of Sumatra's total forest loss.
• Sumatra's peatlands stored an estimated 18.8 gigatons of carbon in 2002, representing 36% of the world's tropical peatland carbon stores.
• The loss of 12.5 million hectares of natural forest since 1985 emitted approximately 7.5 gigatons of CO2, while annual emissions from peatland clearing, draining, and burning were estimated at 1.1 gigatons of CO2 between 1990 and 2002.
• The 'Mega Pulp Project' in the peatlands of Riau, Jambi, North, West, and South Sumatra is described as a climate disaster, covering over 2.2 million hectares, with 65% already deforested for pulpwood plantations.
• By 2008/9, 17 of Sumatra's 38 eco-floristic sectors (EFSs) were classified as 'critically endangered', 'endangered', or 'vulnerable', with 87% of all natural forest loss occurring within these sectors.
• The Sumatran elephant population declined by up to 50% between 1985 and 2007, with the population in Riau decimated from over 1,300 to fewer than 200 individuals.
• The Sumatran orangutan population declined by at least 50% since the 1990s, with an estimated 6,000 to 7,000 individuals remaining by 2007, primarily concentrated in the Leuser Ecosystem.
• The Sumatran rhinoceros population declined by up to 82% between 1986 and 2007, leaving possibly as few as 145 individuals.
• The breeding population of the Sumatran tiger is estimated at fewer than 250 mature individuals, threatened by habitat loss, poaching, and human-tiger conflict.
• Approximately 1.9 million hectares (15.1%) of remaining natural forest in 2008/9 possess high values across all four analyzed categories: forest carbon, peat carbon, mega-fauna diversity, and eco-floristic diversity.

APA

WWF International (2010). Sumatra’s Forests, their Wildlife and the Climate Windows in Time: 1985, 1990, 2000 and 2009. https://www.worldwildlife.org/documents/744/39gyizy6ox_Sumatra_s_forests_report_2010.pdf

Chicago

WWF International. Sumatra’s Forests, their Wildlife and the Climate Windows in Time: 1985, 1990, 2000 and 2009. 2010. https://www.worldwildlife.org/documents/744/39gyizy6ox_Sumatra_s_forests_report_2010.pdf.

Wikipedia

{{cite report |author=WWF International |title=Sumatra’s Forests, their Wildlife and the Climate Windows in Time: 1985, 1990, 2000 and 2009 |date=July 2010 |url=https://www.worldwildlife.org/documents/744/39gyizy6ox_Sumatra_s_forests_report_2010.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{wwfinternational2010sumatras, author = {{WWF International}}, title = {{Sumatra’s Forests, their Wildlife and the Climate Windows in Time: 1985, 1990, 2000 and 2009}}, institution = {WWF International}, year = {2010}, month = jul, url = {https://www.worldwildlife.org/documents/744/39gyizy6ox_Sumatra_s_forests_report_2010.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }