Climbing the World’s Tallest Flowering Tree

With Henry Poerner and Werner Bernstadt

The Eucalyptus forests of Tasmania contain the very tallest flowering plants on Earth. A handful of living Swamp Gums, or Eucalyptus regnans, stretch into the sky at a phenomenal height just below one hundred metres. It’s very possible that, within geologically recent years, the tallest tree on Earth was a Tasmanian Eucalypt.

The tallest known living flowering plant grows near the Tahune Airwalk canopy bridge, in Southern Tasmania. Here, visitors can experience the treetops walking on a sturdy walkway. Throughout Tasmania, a number of tall and giant trees have been recognised and surveyed. Several of these have been measured by handheld lasers, aerial sensors, and treeclimbers dropping tape measures. You can easily see some of these giant trees on the road to the Airwalk at the Zig Zag track, at Mount Field National Park, or in the Styx Valley.

On one hot summer day, I joined two visiting German tree experts in their studies of the Tasmanian forests. Over the years, I’ve been fortunate to climb and study in some of the tallest, oldest, and most picturesque forests on Earth, and we had decided to work together to visit one of the Tasmanian giants. Our skills matched well.

Henry and Werner had known each other for several years, and had just the day before climbed the narrow dolerite spire Totem Pole, one of Tasmania’s most famous and striking rock climbs. Henry has been learning the local flora as a tree doctor, or arborist. Werner was on a short visit from Berlin, where he works as an arborist, climbing instructor, and stunt rigger.

Their professional enthusiasms and experience, like mine, went beyond the ecology and growth of forest trees and to the techniques and history of climbing. We also wanted to share our explorations and discoveries of the arboreal world in a novel and effective way.

On this excursion, we brought up a handful of smartphones to test their capabilities for structural measurements and innovative documentation. One major goal was to produce several photospheres – immersive photographs that could be either mapped to the interior of an sphere, or projected as an interesting flat image.

We met up in the forest early in the morning and pooled our resources, including: hundreds of metres of ropes, metal tools to grasp and release the ropes, and a box of home-made anzac biscuits. After navigating the twists and turns of the dirt forestry roads we arrived at an overgrown road, and from there began our trek into the forest.

The entire forest smelled of evergreen and mint, and the rainforest trees of the understory are covered in moss and lichens. Tree ferns reached outwards with delicate fronds and make viewing upwards difficult. But soon we were near the base of this single tree: the world’s tallest flowering tree, the tallest tree outside of Western North America, and the tallest tree in the Southern Hemisphere.

The world’s tallest flowering plant is, at first glance, indistinguishable from the other ultra-tall eucalypts in the valleys of Southern Tasmania. It has a base with stringy bark, and a long, bright, trunk that shoots into the sky. Large dead branches were being hidden by younger green resprouts. Ribbons of bark hang peel of this long spire, and branches of all sizes are holding a heavy load of this flammable material. This tree was notable in that it was surprisingly asymmetrical, with most branches on one side, and it was fantastically tall.

Like most of the very tallest eucalypts, the tree was beginning to decay and die from the top down, and it’s conceivable that it would lose height and another superlative tree would gain people’s attention. But unlike most other tall eucalyptus trees, this one had living and healthy uppermost branches, and the very highest point was therefore a green leaf – not a grey flake of rotten wood.

Henry and Werner began setting the lines, and I scouted the hillside for clear points where we could look into the tree with cameras and binoculars. The tree ferns and the rainforest canopy made this exceptionally difficult, and once they were in the branches of the tree they would be shaded by the leaves.

Climbing into the lowest branches of a massive tree always gives me a few moments of philosophical thought. I’ve learned to control it, and to simply climb on up the rope, but hanging in space on a tiny cord sparks important questions worthy of strong consideration. What am I doing here? Has anything changed from our initial assessment of this branch’s strength? And, what will I discover when I enter the wooden arms of these titanic living creatures?

My two colleagues moved from branch to branch efficiently and effectively. Henry observed that it was just like climbing any other tree, only higher. This also meant that we were handling larger quantities of rope, and that it was harder to communicate. By throwing the ends of the rope, or a throw line with a weight, over successively higher branches, we were able to position ourselves higher and higher, and to protect ourselves from the alway-present danger of falling.

Watching these two arborists, I learned new ways for combining different rope work disciplines. In addition to to the static, non-stretchy ropes of the tree climbers and cavers, we also had the dynamic, stretchy, ropes of the rock climber and mountaineer. These allowed us to move more fluidly between branches, and to use the hands and feet that we have all inherited from our tree-climbing ancestors.

From branch to branch to branch to branch, and eventually highest point on the stem was reached. We set a direct line – just a few centimetres short of one hundred metres – down to the ground, and with this access point secured, began the serious business of hanging out in the hammock and having a picnic lunch.

At the top of this tree, the stem had broken off. The stub was still larger than we could put our arms around, and this hinted that at one point it was substantially taller. Undoubtedly, this tree had been taller than one hundred metres in the not-so distant past.

You could look into the stub and see a collection of leaves and fruit. In other trees I’ve climbed, in wetter climates, this would have been a green aerial garden of moss and ferns, but in this tree it was dry and empty. This indicated that the tree was not yet so rotten as other ultra-tall eucalypts, and that it perhaps had several years remaining in its lifespan.

From the sides of the stem, just below this stub of dead wood, several strong, healthy, and slender branches reached outwards and upwards. One of these was the actual high point of the tree, and the tree was doing an incredible job of bringing water up to it at such a height. While these branches will continue to grow, it is unlikely that they will ever again attain the height of the unbroken stem.

These “epicormic” resprouted branches allowed us to set up a spider web of safety ropes and to explore our immediate surroundings with as much security as could be attained more than three hundred feet off the ground. This also allowed us to relax and reflect on this amazing experience.

We were surrounded by fragrant leaves and small, compact fruit. Depending on your choice of words, these gum nuts were the world’s highest fruits!

We compared notes about the growth and decay of this tree and its neighbours. A large eucalyptus nearby, while substantially shorter, had a much fuller crown of large branches, and clustered on the ridge above us were other soaring ancient trees. Below us, the rainforest sassafras, myrtle, and blackwoods were clearly distinct as their own arboreal islands. Below them, the tree ferns were like starbursts of green lace.

We could clearly see the Huon River and harvested forests of different ages in the valley. In the distance were the jagged mountain peaks of the Tasmanian Southwest wilderness – dolerite in giant crystal columns, and shining white quartzite carved by glaciers.

I began the long descent, but stopped regularly to take the photospheres. This involved spinning on a rope and leaning in all directions, taking overlapping photographs linked to the gyroscope of the phone. Sometimes, the branches hindered my ability to move and other times, they allowed me a comfortable place to stand. The smartphone software struggled with the complexity of the environment and the constant change: the wind was blowing the leaves gently and the algorithm could not match up the branches in the overlapping photos. The wind and the distance of rope above me meant that I also was drifting slightly in space. On other documentation projects, I’ve set up a tripod with a custom-made swivel to take clean photospheres – refining this technique is the next step for this project. For all of these concerns, I still managed to produce a small handful of spheres which you can explore – you can view them on the internet and look in all directions, up into the branches and down along the trunk to the forest floor. They’re linked below, and there are images included of them projected as “tiny planets” and as rectangles.


When I reached the ground, I sat for a few moments to let the circulation return to my legs. I then untangled from the lanyards, clips, and ropes that had been so organised when I was in the air. Henry began his descent, and had the remarkable experience of abseiling one hundred metres in a single drop. Weaving his way through the branches, he came down to the ground much more quickly and landed gracefully.

Werner began the difficult and slow process of derigging the tree. He had to untie and manage all of the separate pieces of rope we had left above. When two long ropes hang in space and are threaded past branches together, they cannot resist becoming involved with each other. No matter how good your rope management, you can find yourself inevitably dealing with unexpected tangle. In addition, the weight of the rope hanging beneath you makes handling them difficult — sometimes managing a line requires pulling up dozens of metres of rope.

He sorted it out speedily and safely, and was soon standing on the lowest branch before his final abseil. Before I could even set up the camera into position, the professional stuntman had jumped off of the branch and slid perfectly down the rope to land on the forest floor.

With everyone safely on the ground, we pulled down and packaged up our ropes, and trudged on out to the forest road and civilisation.

There are many tall trees in the forest, and the great height that makes this one so notable does not necessarily mean that its crown is the most complex or intricate. It felt like climbing in other tall Eucalyptus regnans, but with the added element of phenomenal height. In a word, the world’s tallest flowering tree could described as focused. It had put tremendous energy into growing upwards and had not put resources into branching out.

Within our lifetimes, this tree may very well lose more upper stem, and another flowering plant may gain the temporary and invisible prize of being the world’s tallest. It may also stand as the tallest for another century – who can say? In the meantime, during this short interval, we were honoured to safely ascend into its branches,and happy to be returning safely to the solid ground upon which we all live.


View the immersive photo-spheres:

You can explore these interactive photospheres by touching the screen or dragging the mouse. You can zoom in, look in all directions- including straight up and down! Look for clickable information points, and for portals that will take you to another place within. To experience this environment in full screen, click the small button in the upper right.

In the Branches of the World’s Tallest Flowering Tree