Using Drones for Forest Monitoring

There’s just one place left on earth where tigers, elephants, orangutans, and rhinos live together in the wild: the Leuser Ecosystem World Heritage Site on the Indonesian island of Sumatra.

One of the last remaining intact rainforests in all of Indonesia, the Leuser Ecosystem spans 2.6 million hectares, including lowland and montane rainforests, wetlands, and over 185,000 hectares of carbon-rich peatlands. It is a crucial source of clean drinking water and agricultural livelihoods for over four million people. In fact, the ecosystem services provided by the Leuser Ecosystem, including 1.6 billion tons of carbon and the provision of water to 4 million people, are valued at over US$600 million annually.

However, Leuser is highly endangered, with threats accelerating since the end of the Acehnese rebellion and civil war. Post-war stability is bringing rapid invasion of commercial interests in palm oil, rubber, and logging, with companies legally and illegally deforesting the Leuser Ecosystem at astounding rates. Between 1985 and 2009, half of Sumatra’s forests were destroyed. The decimation continues today; despite its protected status, Leuser has lost one-fifth of its lowland forests to illegal commercial activities in just the past five years. At that rate, the forest will be completely destroyed within two decades.

The primary threat to this unique ecosystem is illegal palm oil expansion. As global demand for palm oil rises, oil palm growers seek to multiply the acreage of this valuable crop. Unfortunately, there is little unoccupied land left in Indonesia, leading growers to encroach illegally into the country’s dwindling but exceptionally biodiverse protected areas.

In addition to palm oil, it faces accelerating threats by illegal and commercial interests in logging, mining, ill-advised energy projects, and the fragmentation of forests by new roads. The fires from this widespread destruction have caused major haze pollution from Singapore to Jakarta, resulting in huge economic losses and public health issues.

Due to this destruction, Sumatra’s unique megafauna species are in serious danger. Of the world’s 80 remaining wild Sumatran rhinos, Leuser contains 50—the last viable population of this species on Earth. Of just 400 remaining Sumatran tigers, more than 100 live in Leuser, which is one of only two regions with enough breeding females to sustain this subspecies.

Finally, 85% of the world’s critically endangered Sumatran orangutans call this forest home. As Sumatra’s forests disappear, it seems increasingly likely that Sumatran orangutans will become the first great ape to go extinct. All of this has led conservationists to call Leuser one of the “world’s most irreplaceable protected areas” – if this forest disappears, these species will go with it. 

Global Conservation has funded the acquisition and deployment of advanced mapping UAVs/drones to document illegal deforestation within and around the Leuser Ecosystem. Both fixedwing long-distance drones and quadcopters are being used to uncover large-scale rainforest destruction for illegal palm oil plantations within the Gunung Leuser National Park and Greater Leuser Ecosystem.

Because they allow the Leuser team to see large areas of forests far from access roads, drones are proving invaluable in the fight to get government, community leaders and law enforcement to stop forest and wildlife habitat destruction.

Drones are relatively cheap, can cover hundreds or even thousands of hectares in a short space of time, and can beam back live video transmission. The Leuser Ecosystem team are currently using drones in three regions of the ecosystem to monitor encroachment and forest loss. They are also conducting high-resolution mapping of illegal logging and forest destruction based on Global Forest Watch fire reporting.

While the use of drones for anti-poaching has been less productive, mapping of forest destruction in faraway areas using drones has proven highly effective. Mapping and imagery are used to prepare police cases against illegal loggers, and in discussions with local communities and their leaders to reverse destructive practices.

Using drones, we documented critical orangutan habitat being destroyed within Gunung Leuser National Park. The next step will be the major task of removing illegal palm plantations and finally, reforestation. The team also attempted to use FLIR thermal cameras mounted on drones to identify poacher campfire locations.

The current models of affordable drones are not yet reliable in flying over deep forest or at night, risking the loss of expensive equipment. However, as the technology improves, we anticipate that thermal imagery for surveillance will become another key use for drones.