The world's tallest known tropical tree has been found—and climbed

In the last few years exceptionally tall yellow meranti trees (Shorea faguetiana) have been discovered growing in Sabah, a Malaysian state on the island of Borneo, again and again. The record height of an individual jumped from 288 feet (88 meters) to 308.7 feet (94.1 meters) in 2016, when an entire grove of 90-meter (295-feet) plus yellow meranti were found. That record has been further eclipsed this week as a team led by the Universities of Nottingham and Oxford, working with the South East Asia Rainforest Research Partnership, announced the discovery of a 330.7-foot (100.8-meter) giant growing in Sabah’s forests (the scientific study on the find is being published in bioRxiv this week, and is in review in a scientific journal).

This discovery is the first 100-meter tropical tree (and the world's tallest known flowering plant) recorded anywhere in the world. If it were laid along the ground the tree would be longer than a soccer field. The team named the tree “Menara,” which is Malaysian for tower. They estimated it weighs 81,500 kilograms, or more than the maximum takeoff weight of a Boeing 737-800, excluding roots.

It's possible an even taller tree is still waiting to be found in the region, the team notes.

These rainforest giants have been found growing in the Danum Valley Conservation Area, at the center of one of the best protected, and least disturbed, tracts of lowland rainforest left in South East Asia. Danum protects Borneo’s iconic and endangered orangutan, clouded leopard, and forest elephants. Danum is also, it turns out, providing refuge for the tallest known tropical trees in the world.

The record-breaking trees are all, so far, of the same species—yellow meranti. It is highly endangered, and IUCN red listed, having been harvested relentlessly for decades. While Sabah’s primary rainforest is under protection, yellow meranti felling still goes on elsewhere in Borneo—often to make molds for pouring concrete and cheap plywood. These incredible trees, each its own mini biodiversity hotspot hosting up to 1,000 insect, fungi and other plant species, can be reduced to planks in a sawmill in a few minutes.

These exceptionally tall trees were spotted by laser scanning the forest from an airplane in 2018. Three dimensional images are built up of the forest canopy, and slowly the giants pop out of the image. However, when laser scanning reveals an exceptionally tall tree, proof of its actual height is gathered in a remarkably low-tech way; someone climbs up the tree with a tape measure.

The job of climbing the tropics’ tallest trees with a tape measure falls to Unding Jami, an arborist and research assistant with the South East Asia Rainforest Research Partnership. Tree climbing is risky and difficult, and it requires a calm mind and a high level of fitness. The Danum Valley team hone such skills by working in primary rainforest every day and playing ferociously competitive games of badminton and soccer in their downtime—in steamy temperatures and high humidity.

On January 6^th, 2019 Unding Jami climbed what would eventually be announced as the tallest tree in the tropics and probably one of the tallest trees left standing in the world. (The tallest known trees are California redwoods, which have been measured up to 379.7 feet, or 115.7 meters.) I interviewed Unding twice, first as he and his team had received news of the new contender and were planning their expedition to measure its height, and again after the successful climb in January.

Tell me about the new giant tree, spotted in a valley near the Danum Valley Field Centre.

When we first found out about the new tree I was nervous of climbing it. The site is very steep, it’s called Rhino Ridge. There’s a valley nearby and a waterfall. In a straight line it’s not that far from the field center but we had to put new trails in and it’s difficult to find—a steep walk to a steep site. The plane measured the new tree at 325 feet (99 meters) and I got 377 feet (115 meters) from the base with a laser sight when I went in on foot. So before I climbed it I [thought it was] somewhere between those two measurements.

The new tree is all by itself, high above the tallest canopy trees, in a small, steep hollow. The science team thinks its record height is due to the hollow providing damp soils and a ridge nearby that offers wind protection. Current theories on the amount of wind stress that trees can withstand, and how far they can pump water and sugars up to their crowns, leads the team to believe that Menara is close to the maximum possible height for an Angiosperm anywhere on Earth currently.

What was it like to climb?

I knew it would feel very exposed [to climb], like you are just hanging in the air. There were really strong winds and a Colugo (flying lemur) nest! It was flying all around as we were trying to shoot the line up into the tree.

It took me 15 attempts to shoot that line 86 meters (282 feet) up to the lowermost branches. Honestly, I almost gave up. We were so lucky to be able to finally shoot the rope over the lower branch.

Once we had the rope up I took nearly an hour to climb up to 86 meters. And then another two hours from there to get to the top to take the final measurement. That last two hours the wind was very strong, and it rained, which slowed me down.

How did you feel when you got to the top?

I was scared but honestly the view from the top was incredible. I don’t know what to say other than it was very, very, very amazing! After we measured it I couldn’t sleep for the whole night

How do you climb a 100-meter tree?

We use a system called rope walking. A rope is catapulted over a lower branch and tied off to a nearby anchor tree. Then we use a harness and one directional ascenders to walk up the rope, step by step, like you’re climbing the stairs. You hook the tape measure onto your harness and climb and check the measurement when you get to the top and try not to drop the tape! It’s not easy. At 80 meters up you’re by yourself in the canopy. You can’t hear [anyone] on the ground anymore. So, we text each other instead.

How difficult is it?

It’s not easy work to do. I climb up slowly, checking the trunk every meter for centipedes, snakes, and things. If there are birds', bees', or wasps’ nests that can be a problem. If I see one from the ground, we will climb at night when they’re less active and shouldn’t attack. It’s almost less scary to climb at night, as you can’t see everything!

If you fall unconscious whilst climbing a tree the chest harness prevents you from slumping into a safe position—head lower than heart. An unconscious climber in that position has only three minutes or so to survive and that means the ground team must quickly get them down using an emergency extra rope.

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I’ve heard you once got into trouble with bees on a climb?

(Laughing) Yes, you could say that. I was climbing a flowering Dipterocarp and those attract everything, bees and wasps and all sorts of insects. About half way up I saw a colony of bees flying past.

I knew immediately that I needed to get down. Rainforest bees can be aggressive and become dangerous, if just one stings you the entire colony senses that and then they can swarm and attack.

The problem was that I had to first change over from my ascending gear, on my harness, to descending gear so I could quickly rappel back down the tree. I was trying to do that and then I saw three bees flying really close to my face. Two flew past me and I thought, ok that’s alright, but then the third bee flew into my helmet and so, of course, it stung me because it was trapped.

That started the swarm. I remember thinking I should cover my face, so I pulled my t-shirt up over my head, closed my eyes and started changing over to my descender by feel. But they were just stinging me all over. My guys on the ground could see what was going on because I had a red t-shirt on and it had turned completely to black because it was covered in bees. I was really starting to worry because I needed to descend fast to get away from them, but I couldn’t see to visually check my gear. So I just kept my eyes closed, felt and thought, that’s right. I just let go and went.

And then I stopped suddenly after a few meters drop. I forgot I had a safety lanyard clipped on, that would stop me falling if something went wrong. That was really bad because, with the safety lanyard on, if I fell unconscious from the stings my ground crew would not be able to lower me to the ground. And by this point I had so many stings.

Some climbers are suspicious of carrying a knife, but my instructor always made me carry one. I remembered I had it at that point and I just cut the lanyard and rappelled, as fast as possible, back to the forest floor.

I was stung 200 times by the time I got to the bottom. I remember thinking I needed to stay conscious long enough for me and my guys to get away from the colony, because of course all the bees had come down with me. I was conscious on the ground for a few minutes but then the stings started to act. I was out for about 40 minutes apparently. I woke up and remember my guys were so upset, they didn’t know if I was alive. They’d put me on my side, and then they’d had to run and try and chase the bees away.

How did you end up doing this job?

I come from a very poor family here. I was born in a logging camp in Sabah and my late father worked as a logger. I grew up seeing many people hunting in the rainforest, cutting the trees and I thought maybe one day I can work to stop [people] from damaging the forest. My parents couldn’t afford to send me and my three siblings all to school so I was only in school for two years; I left when I was 9 years old. When I was 13 I got a job with one of the rainforest replanting programmes, planting seedling to regrow the logged forest. I’ve worked in rainforest conservation since then, with Sabah Biodiversity Experiment and then SEARRP, as a rainforest research assistant. Slowly, as I worked with these groups, I started to understand why the forest is so important, to the whole world really, and why we need to protect it.

The animals in the forest inspire me, the amazing gibbons inspired me to learn how to climb trees. They are just such brilliantly perfect climbers, swinging from tree to tree, jumping everywhere. I wish I could climb like them, just using my hands.

How do these amazing, record-breaking trees help us to understand the forest and to ensure it is protected?

This kind of expedition is good for our community and for rainforest conservation. And it’s about friendship too, a successful climb like this is not about one person, you need a great, skilled team.

It is important to know that conserving the primary rainforest is working—some of these unique, giant trees are still out there, they haven’t all been lost. I’m hoping my three young daughters and all the future generations still can see these trees standing when they grow up.

This interview has been condensed and edited for clarity.

On the expedition to climb the new tallest tropical tree were Jamiluddin Jami (Unding Jami); Fredino John; Azwan Tamring; Azlin sailim; Ahmad Jelling; Sabidee Rizan; Fyenlyvicy Thomas; Mohd Fadil Karim; Elizabath Rusili; Johnny Larenus; Dedy Mustapa; representatives from Danum Valley Management and Yayasan Sabah Group.