What Is Haze?

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.

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.


How Are the Fires Affecting Life in Sumatra?

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. 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 effect on the burgeoning, largely impoverished, human population (some 70 million people are estimated residents of Sumatra and Indonesian Borneo) in the region was alarming and equally alarmingly underreported globally. On September 14th the air quality index in Pekanbaru, Riau, my Indonesian hometown, reached 983 on the Pollutants Standards Index (PSI) scale that tops out at 1000 and indicates anything over 100 as dangerous. This prompted a second wave of people leaving the city (including me; the first wave occurred when the haze began in early September), heading overland to Padang, West Sumatra, since the Pekanbaru airport closes at a PSI reading of about 250 PSI. Although many in Pekanbaru were able to escape to slightly more breathable air, millions of people across Borneo and Sumatra don’t have the resources to escape. An estimated 500,000 people reported to health care centers for respiratory related problems, schools were closed (yet children were excited and played outside as if they had been given an extended holiday) and flights were cancelled, costing Indonesia alone billions of dollars.

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Taken on September 14th. Air PSI 983.
Life continues as normal…
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The city statues wears a mask

Through it all, I have been shocked by the seeming lack of government response. There was a rumor evacuations were going to start, but after a while it became apparent this was, in fact, just a rumor. The extent of the government’s health efforts included telling people to stay inside and occasionally passing out masks. The thing about hazardous air is that it gets everywhere. It permeates tents, enters malls and stores, and doesn’t care about the 1cm inch gap between your cheeks and a cheap hospital mask. The free masks that are handed out are usually not sufficient to filter out the harmful PM2.5 particulate matter and these masks are often completely sold out during haze season. In most areas of Indonesia, peoples’ home are fluidly integrated with the outside; either their kitchen is outside, they walk outside to the bathroom, or their dining area is outside. In rural Sumatra, many houses are made of wooden boards, tin sheets or concrete that have open windows and large gaps or cracks. Telling people to stay inside is basically the same as telling them to do nothing. Even if windows and doors are truly sealed, air conditioners bring in air from the outside.  There is no escape.

How Has it Affected My Research on Sumatran Tigers?

It is a horrible feeling to be trapped in a place where you know you shouldn’t be breathing the air. I returned from a short break to the US in early September and I was told I shouldn’t head to Pekanbaru from Jakarta by coworkers. I waited around a week, saw a clear window and returned to Pekanbaru on a Tuesday. I was there for a few hours and had been told that the air was clearing. I landed completely shocked, into a cloud of brown haze. This was not clear air.  I bought a ticket to return to Jakarta since I had a few items to take care of there the following morning. That afternoon, PSI levels reach 983. I was encouraged to leave as fast as possible. I tried to fly out several times over the next several days, but the airport was cancelled for several days. I was trapped. I checked into a hotel, since I live in a traditional Indonesian home, and was thankful I had bought masks before returning.

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. 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.

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. If the global price of oil palm drops, motive to clear land could decrease. Unfortunately, this creates a local problem in addition to the altered weather patterns caused by clearing land for oil palm: it would put locals in a bind when they don’t have an alternative for income. The World Wildlife-Fund Indonesia is attempting to build up eco-tourism in Riau as a potential income alternative and organizations elsewhere are also starting to explore their local options. I am sure there is a solution where healthy forests with robust tiger populations and humans can live peacefully in the same landscape, but until NGOs, the global society, and the Indonesian government work together to find this solution I am afraid that more people each year will visit the emergency room and fewer tigers will be roaming our forests.


 Cheyne, S.M. 2008. Effects of meteorology, astronomical variables, location and human disturbance on the singing apes: Hylobates albibarbis. American Journal of Primatology, 70: 386-392

Dalerum, F., Cameron, E.Z., Kunkel, K. and Somers, M.J. 2009. Diversity and depletions in continental carnivore guilds. Implications for prioritizing global carnivore research. Biology Letters 5: 35-38.

Dinerstein, E., Loucks, C., Wikramanayake, E., Ginsberg, J., Sanderson, E., Seidensticker, J., Forrest, J., Bryta, G., Heydlauff, A., Klenzendorf, S., Leimgruber, P., Mills, J., O’Brien, T.G., Shrestha, M., Simons, R. and Songer, M. 2007. The Fate of Wild Tigers. Bioscience, 57(6): 508–514.

Ranganathan, J., Chan, K.M.A., Karanth, K.U. and Smith, J.L.D. 2008. Where can tigers persist in the future? A landscape-scale, density based population model for the Indian subcontinent. Biological Conservation, 141: 67-77.