The following article was originally published in Sidetracked Volume 20

The Sumatra Megatransect: A 500 km trek across Sumatra to carry out a ‘MegaTransect’ survey of the island’s birds. The expedition included the first biodiversity survey of a previously un-researched montane forest and an attempted first ascent of Mount Kurik.

I was sleeping on creaking boards when it bit me. I woke instantly, but my arm already felt odd, as if it was submerged in warm syrup. I lay face up, staring into darkness. Something was moving under the small of my back, and it felt like a snake. Shit. I needed to get out of my sleeping bag.

Unfortunately, getting out of a sleeping bag quickly is almost impossible. I inhaled, tensed for the inevitable second bite, and scrambled out. Miraculously, no second bite came. I pulled the sleeping bag’s hood tight to trap my attacker, flicked on my head torch, and assessed the damage. There was a neat pair of puncture marks above my elbow and a painful swelling spreading across my upper-arm. I needed to know what had bitten me, so I picked up my sleeping bag and inverted it tentatively. A foot-long thing fell thrashing to the ground and I trapped it with an empty Tupperware. It was as long as my forearm and as thick as a finger, with a flattened body and fangs like a cat’s claws. It wasn’t a snake; it was the mother of all centipedes. I couldn’t bring myself to kill it, so I flung it in a bush and collapsed. The pain was exquisite, but I was also exhausted and exhaustion eventually won. I slept deeply for the rest of the night, and miraculously, was pain-free in the morning.  

I was in Sumatra, the largest island in the Indonesian archipelago. The interior is dominated by two regions: in the west, the Barisan Mountains, which contain several active volcanoes, carve the backbone of the island; in the east, complex river systems carry silt down from the mountains, forming vast lowland swamps. My girlfriend Iris and I were walking 500km of this extraordinary landscape, conducting a ‘megatransect’ survey of bird species across as many habitat types as possible, from pristine forest to oil palm plantations. Along the way, we planned to use our pristine forest remit as an excuse to attempt a first ascent of a remote 3,000m peak, Gunung Kurik (Mount Kurik).

We began our journey in Aceh, a semi-autonomous region occupying the north of the island. Once an independent nation, Aceh fought against Indonesian government forces from 1976 to 2005, finally succumbing in the aftermath of 2004’s devastating Boxing Day Tsunami. In spite of this violent past, Aceh's forests remain some of the richest outside of the Amazon, with Gunung Leuser National Park, the most biodiverse forest in Asia, straddling the province’s border with North Sumatra. The park is home to Sumatran orangutans, Sumatran tigers, Sumatran rhinoceroses, and Sumatran elephants. All four are both endemic and critically endangered. Logging has eaten away at Leuser for decades, roads reach to the core of the reserve, and the groundwater supply is nearly exhausted. 12,000 hectares of forest (approximately the area of a major city) is lost annually. However, there are other forests, hidden away in the mountains to the north of Leuser, unprotected and unresearched. It was these forests that we had set out to study.

After a jarring night bus journey, we had met up with local mountaineers Saed and Roy in Blangkejeren, the nearest town to our start point. We bought supplies at the market: rice, salted fish, chillies, and biscuits. Permits were obtained by Saed through contacts in the town's police, and after three days of preparation, we were ready to depart. Each of us would initially carry a 25kg pack, which would thankfully lighten as we buried food en route for the return journey.

We spent the first two days wading upstream, away from rice paddies and into dense forest. The river was bereft of fish, but its banks were home to knobbly grey toads that played dead when picked up. On the first day, we met a trio of young men from the village, walking downstream with the corpses of about thirty strikingly-coloured birds on a line. They had passed the morning camped beneath a fruiting tree armed with small-bore shotguns. So the first animals we identified were dead ones. Luckily, our next memorable encounter was a happier one. It was day three, and we had camped on a riverbank. As we ate breakfast, a group of five hornbills landed directly above us, crashing through the branches like a flock of pterodactyls. For the first time, the forest around us felt truly primaeval.

In every expedition, there is at least one moment when the whole thing looks like a big mistake. For the Sumatra Megatransect, this moment was our second evening at basecamp beneath Mount Kurik, when Roy, the toughest of us, looked like he might be dying. He sat slumped by the fire, head lolling, eyes closed, muttering prayers in Arabic under ragged breath. His hand was wrapped in tissue, tape, and plastic. Beneath this makeshift bandage, his ring finger was cut to the bone – the result of a machete slip as he scouted our route. Worse, it was Ramadan, and as well as food and drink, Roy had refused painkillers and antibiotics until sunset. The cold didn’t help either. We neared an altitude of 3,000m and, despite our proximity to the equator, the air was bitter. Darkness fell and Roy was given a double-dose of almost everything in our meagre med-kit. Somehow, Saed managed to coax a few sodden logs to burn. Forest mice, with absolutely no fear of fire or humans, scuttled over us during the night. They were actually quite sweet, but they made sleep difficult and raided one of our food bags. In the morning I shuffled over to Roy, who had spent the night sitting in a foetal position. He looked up at me. ‘How did you sleep?’ I asked.  ‘I didn’t,’ he replied. ‘I prayed for morning.’ He grinned at the sunlight and stood up stiffly. Morning had broken and there was hope after all.

We filled every spare container, including all available plastic bags, with water from a nearby stream. The mountain forest was constantly wet and frequently experienced intense rainfall, but any surface water either drained rapidly into the loose soil or was absorbed by the pervasive vegetation. The stream itself, a series of small rapids and waterfalls when we arrived, had been reduced to bare gravel and a few shrinking pools. The local monkeys were understandably protective of this precious resource. They demonstrated this by urinating on us when we weren’t looking.

It was Iris’s 20th birthday and, with our water supply arranged and Roy looking somewhat healthier, we were in the mood for a party. Our usual ration of rice and dried fish was replaced with a banquet of florescent-yellow macaroni cheese. A sachet of jelly (more transportable than cake) was prepared. Matches were used instead of candles. The Sumatran love of singing ascendant so even the mice turned up for the party. In better spirits, we discussed plans. Mount Kurik was unclimbable from our current position, and we had neither time nor supplies to cut around to the other side of the mountain. We decided to cut our losses and attempt Mount Lembu, a neighbouring peak first summited by Dutch soldiers during colonial rule. Saed had led the second ascent in 2014, but the mountain’s biodiversity, like that of the forest around us, had never been recorded in any form.

Saed, Iris, and I set off before first light. Roy remained at basecamp, and in the event that we did not return within 48 hours, he would have to walk for at least two days before he could get a phone signal and call for help. Climbing a mountain in Sumatra is effectively fighting your way through a near-vertical hedgerow. Plants cover everything and moss covers every plant. Both moss and plants are soaking wet, and within minutes, so are you. Soaking wet means freezing cold. After six hours of crawling and clambering, we broke out above the treeline and onto an open ridge. Our constricted horizons exploded. An unbroken mantle of emerald forest stretched endlessly in all directions and the whooping calls of gibbons echoed up from the valley floor a thousand metres below. The air was clean and the sun was warm. We shared a half-packet of biscuits and dried off our sodden clothes. The push to the summit was spectacular. Ribbons of cloud fell away into a blue abyss. After weeks spent in claustrophobic jungle, walking in the open felt like flying.

The summit was marked by a small concrete pillar. We scraped away almost a century of encrusting vegetation and found ‘March 13th, 1931’ inscribed at the base, along with the names of a half-dozen Dutch soldiers. The lunatics must have carried that concrete for weeks. Just the thought of it was surreal.

We finished the biscuits with our backs to the pillar. An ocean of green rolled away in all directions – and analogy with the ocean was the only thing that allowed my mind to absorb its scale, for no forest that I had grown up with could compare. The only valid reference I had was off standing on the cliffs of my native Cornwall, awed by the immensity of the Atlantic. In the far distance, we could see the silhouette of Gunung Leuser, the mountain namesake of Gunung Leuser National Park. It was strange to think that the extraordinary forest that surrounded us had not been included in the park, and in fact, lacked even basic protection. Perhaps it had survived because the recent conflict had kept corporations at bay, or maybe the steep terrain made its destruction uneconomical. Either way, its survival was due to luck, not law, and luck always runs out eventually.

It was time to descend. Iris and I had 400 kilometres left to walk. Along the way we would accidentally stumble into the fallout from an active volcano, sleep in illegal stilt-houses hidden from the government’s regime of ‘improvements’, and I would have my legs attacked by a machete-wielding toddler named Erwin. But what would really stand out was the unerring kindness and generosity of the Sumatran people. In almost every village we were welcomed into someone's home. The last and perhaps most memorable of these stays was when we finally arrived, ill and exhausted, at the Indian Ocean. We were discovered by a local teacher and invited to dinner. We spent the following two weeks living with his extended family and heading out to the reefs with local diver-fishermen. When it was finally time for us to leave, we discovered that they had expected us to stay until Christmas, which was five months away. After nearly two months and 500 kilometres, the final lesson was this: it is almost impossible to overstay a Sumatran welcome.