Tigers in the Haze


The recent smoke haze in Indonesia caused by excessive burning of forests and peatlands was a topic of conversation at COP21 and an all too vivid example of how forest loss can drive climate change. The fires “contributed to Indonesian emissions, surpassing those of the U.S. on 47 of the 74 days to October 28 during the recent haze crisis. More than half a million people were diagnosed with respiratory illnesses and at least 2.1 million hectares of land went up in smoke.

One of the Philadelphia Zoo’s partners living in Sumatra, Erin Poor, is a PhD student conducting research with the Virginia Tech Sumatran Tiger Project, a Philadelphia Zoo Global Conservation Prize winner. Erin is studying the detailed habitat use and movements of tigers in the Riau Province Conservation Landscape in order to identify which areas of palm oil plantations tigers use and why. She recently wrote about her experience with the haze and its impact on her work…

Erin Poor, the Virginia Tech Sumatran Tiger Project

Have you ever walked next to a campfire right when the winds shift slightly and inhaled a big whiff of smoke? That is what living in Sumatra was like during September and October 2015. Granted, fire is a constant presence in Indonesia, but during these two months every year, and particularly during El Nino years, the air becomes unbreathable. I had never experienced the ‘haze season’ before and even though I had been warned, there’s no way to understand the severity of the situation until you experience it first-hand.

In a haze of smoke and next to a former mine pit.

On any given day driving around the province to field sites, or even driving from my home to my office, I see numerous fires burning. The vast majority of these are small fires, set by families and neighborhoods for trash disposal. Other small fires are set by families clearing small plots of land near their house to plant a garden or small plots of oil palm. These fires are usually tempered by rains, but at the end of almost every dry season, in August through October, many of these fires aren’t naturally put out. With no natural soaking, fires spread, causing the land to dry even more and making natural rain even less likely. 2015 was arguably the worst year on record for haze in Indonesia. Surprisingly, even though haze has been a problem in the region for 18 years since large-scale oil palm plantations began being planted, the effects on unique and diverse wildlife of the region are little studied.

Indonesian fire fighters and military personnel extinguish the wildfire on a peat land in Rimbo Panjang, Riau Province

What we do know is that weeks of haze block out sunlight and increase unbreathable chemicals such as carbon dioxide concentrations in the air, which could have an impact on photosynthetic processes, in turn affecting forest health. If forest health is impacted, the impacts can trickle through the entire ecosystem. For example, reduced fruits on a tree could mean reduced survival for gibbons, reduced gibbon survival could result in a decreased population, resulting in restricted seed dispersal in future years, resulting in a change in forest tree composition and a completely altered forest. But, we don’t know if this is happening. In the only study clearly focused on the effects of fires on wildlife, Cheyne (2008) found that gibbons called significantly less during periods of haze than periods of clear air, indicating impacts on gibbon communication and territory defense.

baby orangutan
Orphan orangutan in the care of Yayasan IR (International Animal Rescue)

More recently, where fires came within 1km of an orangutan rehabilitation center on Borneo, there are reports that the orangutans at the center suffered respiratory problems, several juvenile orangutans were found without mothers and several adult wild orangutans were found with burns on their bodies. Staff speculates that wild orangutans may suffer temporary malnourishment due to movement restrictions and reduced access to food. This could be the case across burned areas, but unfortunately the effects on Indonesia’s unique wildlife such as Sumatran tiger, Sumatran rhino, pangolin, clouded leopard, Sumatran elephant, various langur species, and Sumatran orangutan remain unquantified.

The Sumatran Tiger Project camp at the Rimbang Baling Wildlife Reserve

Because there aren’t air quality monitors or good internet connections in most areas of Sumatra, save for the capital cities, it is very difficult to know what the air quality is in other regions. I tried to send my team to survey for tiger scat samples in the southern area of the province, thinking that the air quality would be better, only to find out a few days later they were camping next to a fire and starting to have chest pains.

sampling soil
Sampling soil during a period of hazardous air quality

All field teams were recalled immediately, and field work had to be put on hold for two months – two months during which large swaths of potential tiger habitat were burned. During their short field trip, my team met several local residents. The villagers reported hearing the roar of a tiger within the few past days. When asked why and where, the residents said the tiger was mad his forest was burning.

In November, rains started and we were finally able to return to the field, eager to see what the damage was. Although I knew burning was occurring close to Pekanbaru, I was still shocked to see the landscape. Driving up on hills in a corridor between Rimbang Baling Wildlife Reserve and Bukit Tigapuluh National Park afforded us clear views of scorched black earth with small, bright green young oil palm leaves shooting up into the bright blue sky. In some areas, where fires had raged far beyond control, adult stands of oil palm were burned, too.


In some areas, I was reminded of fall in the Midwest – tall trees dangled orange or brown leaves where bright green trees wrapped in vines should have been. We were thankful the forest within the protected areas, although shrinking slightly every year, still seems to be largely in-tact, hopefully leaving islands of safety for tigers, their prey, and other valuable wildlife.

Path behind the Flying Squad Camp, where tiger foot prints are still occasionally seen. We encountered some nice flowers along the way.

Wildlife in Asia is at higher risk of extinction than on any other continent (Dalerum et al. 2009) and threats to tigers are growing more rapidly than the rate at which accurate and reliable scientific information is being collected (Ranganathan et al. 2008). Only 7% of the original tiger range remains (Dinerstein et al. 2007) and the recent global population estimate of tigers is at an all-time low.

The decline in the tiger population is a multi-faceted, multi-scale, and far-reaching problem, affecting nearly every country in the world through activities such as trade in tiger parts, tiger consumption, tiger poaching, illegal logging and conversion of tiger habitat, consumption of agricultural products grown on such converted land, negligent and corrupt law enforcement and/or insufficient funds to support law enforcement.



Right now, in Sumatra, oil palm is a large part of this problem. It is a global environmental problem because Indonesia produces nearly 80% of the world’s palm oil and it is incorporated in scores of products world-wide. These purchases are driving the market, and driving the motive to burn land every year to plant oil palm.

Send a message to companies that use palm oil in many of the products we like to eat. Ask them for an update on their promise to make sure their palm oil doesn’t destroy habitat for wildlife.

[From “Burning Bright; A Tiger Researcher’s Experiences and Observations during the Recent Indonesian Fire and Haze Crisis,” by Erin Poor]