From Rooted Tree to Voyaging Boat

Earth Observatory Blog

From Rooted Tree to Voyaging Boat

A dipterocarp tree is made into a long boat (Source: Photo on the left by Hugh Lansdown/Shutterstock, and photo on the right by Juniator Tulius)

Different rainforest trees grow on an island called Siberut; one of four big islands of the Mentawai Archipelago located off the west coast of Sumatra, Indonesia. Katuka is what Mentawaians call one family of these dipterocarp trees. These trees have very hard wood and are widely used for construction and crafting.

I want to tell you the story of one katuka tree in particular. This 400-year-old tree will soon surrender its life to serve the needs of the people. 

A Giant Falls

The impressive size of a dipterocarp tree (Source: Frank Lucas/

As the sun rises over Siberut Island, a Mentawaian called Aman Ani and his fellow villagers sharpen their axes. They prepare their meals, as well as an offering for the forest spirits. Later, they sit quietly in a motorised canoe as they cruise upstream. Some of them are smoking cigarettes. All of them reflect, knowing they will soon execute a tree that has been standing on the island for nearly 400 years. As they approach the foot of a hill, the pilot slows the outboard engine.

The villagers walk into the jungle. They clear their path through the thick forest searching for the ideal katuka tree. They find several and eventually select one. They prepare a small ritual asking the forest spirits for permission to bring the tree down.

A man with a chainsaw looks up to the sky to estimate where the tree will safely fall. He starts cutting the tree. The tree begins to shake and crashes down like a mythical giant collapsing and exhaling his last breath. Everyone observes a moment of silence for the fallen katuka tree.

The villagers clean the trunk of epiphytes, harmless plants that grow on a host tree, and cut off its branches. The trunk measures 140 centimetres (cm) in width and 1,580 cm in length. 

Shaping the Canoe

The katuka tree takes on a familiar modern form (Source: Juniator Tulius)

Aman Ani, the master of canoe-making, inspects the log. After rolling the log into position, the master begins to shape the canoe with an axe. The man with the chainsaw then works on it. Within a few days, the structure of a canoe emerges and a week later, the canoe is finally completed.

Before pulling the canoe out of the forest, the villagers again perform a ritual for the forest spirits to protect the canoe from bad spirits and harm.

After floating on the river for a week, the canoe-makers prepare to transport their latest creation to Pokai, a harbour village on the eastern coast of Siberut. The 13-metre long canoe is tied to a wooden ferry travelling to Muara Siberut, another harbour located on the south of Siberut, ready to be delivered to a buyer called Marnis.

From Canoe to Boat

The transformation from canoe to long boat (Source: Juniator Tulius)

As soon as the canoe arrives in Muara Siberut, Marnis strands the canoe on the beach. He and his friends prop it up on two big logs so that it does not rest on the sandy soil. They then fill the canoe with water to slowly widen it. Every two days, Marnis checks the canoe and uses wooden sticks to widen the canoe further. Two months later, Marnis and his friends pull the katuka canoe to a workshop. Marmudin, a man who works with Marnis in Muara Siberut, will now transform the canoe into a long boat.

I sit down with the boat-makers to order the boat for the Earth Observatory of Singapore (EOS). Even though I have money with me, Marnis refuses to accept payment until the boat is ready. He trusts that I will pay him later. If we decide to cancel our purchase, he would not mind. He tells me that other people will buy his boat one day.

The boat-makers take a rest (Source: Juniator Tulius)

Marmudin places a thick plank on the tail-side of the canoe for two outboard engines that will motorise the long boat. Later, he shapes more planks and attaches them to the bow and main body of the canoe. After completing the main construction, the boat master makes the boat’s hood from fibreglass. Several helpers close small holes found in between the planks with natural resin collected from the forest of Siberut. After 25 days, the construction of the long boat is finally completed. The boat is officially named Katuka.

The Adventure Has Only Just Begun

The finished boat (Source: Juniator Tulius)

In 2013, Katuka’s adventurous journeys began. It explored the coastlines of the Mentawai Islands, Nias, and Sumatra to help scientists from EOS and the Indonesian Institute of Sciences better understand the tectonics of the region and the behaviour of the active faults the Mentawai islands lie upon.

The Katuka boat proudly braves the seas (Source: Juniator Tulius)

Here’s wishing Katuka a long and safe journey along the shores of Sumatra and the Mentawai islands!



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