Kim Calders discovered his passion for scanning trees when doing his PhD in Hallerbos forest, near Brussels. As a bio-engineer, he has been travelling the world with his LiDAR scanner ever since. Along the way, he has ended up face to face with cassowaries and elephants, and collaborated with artists to make a forest sing. A story in nine pictures.
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1. Trees in 3D
Kim Calders, faculty of Bioscience Engineering: “Here it is: the LiDAR scanner. LiDAR stands for Light Detection and Ranging. In fact, it is a distance meter, but one that measures thousands of positions per second. The scanner that we use is quite small and sits on a tripod. LiDAR scans are used to create 3D point clouds. In this way you can portray objects very precisely in 3D-models.”
“The technology is also used for many other applications. iPhones actually contain a LiDAR scanner, allowing you to determine the depth more quickly when taking a photo. This produces sharper images. The videoclip from the hit House of Cards by Radiohead features LiDAR technology as well.”
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2. Calculating volumes
Together with my colleagues from the research group CAVElab, short for Computational & Applied Vegetation Ecology, I scan trees. We turn the points perceived by the scanner into a 3D model. We can use this to calculate a tree’s volume. And that is necessary to evaluate the amount of carbon contained in a tree.”
“The very close proximity of the recorded points means the result ends up very similar to a Virtual Reality image. On this scan you can see a tree from the bottom up. The colour variations indicate the differences in height.”
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3. Teamwork
”Scanning is fun. Of course, we can’t resist posing ourselves from time to time. The scanner needs to travel a full circle in order to complete the recording. That means we have to stand still for two whole minutes, a little like the early days in photography.”
“We made this scan a few years ago, when our colleagues from the Forest & Nature Lab were keen to explore the potential of LiDAR scans for their own research. Once you discover LiDAR, you soon get a taste for it. Indeed, our team has grown fast. It may surprise you, but we are currently one of the world’s largest LiDAR laboratories involved in forest investigation.”
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4. Special bond with Australia
“This scan was taken in Australia. I have a special bond with that country. While writing my thesis I went there to conduct fieldwork. At that time, LiDAR was barely used for applications in nature. It was more common in Australia. During my doctorate I headed back there. I also met my wife there later on.””
“Australia contains almost all ecosystems that are found across the world: from mangroves and tropical rainforest to savannahs. Furthermore, the impact of climate change is considerably more obvious than here, for example. That makes it an excellent country for me to carry out forest research. Another advantage: in Australia it is easy to organise everything you need for your fieldwork beforehand, which is not always the case in every country.”
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5. Crown shyness
”In the forest, I don’t see individual plants and trees. I see structure. Can you spot those white edges between the crowns of the trees? That phenomenon is known as crown shyness: the crowns take up as much room as possible, but without touching each other."
“To make a complete study of a forest you naturally need to combine all elements, such as tree species, structure and temperature. We do this by working with colleagues from other research groups and institutions.”
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6. Photobomb
”Cassowaries can be very dangerous. But, above all, they are very curious creatures. This one came to check out our field station in Australia. We had just got everything installed when the bird came closer. I quickly turned on my scanner, because I didn’t want to miss the chance of this photobomb. Thanks to the bird’s curiosity, it was a very detailed scan: the cassowary took its time to have a good look around. It also stood still for long enough to make a detailed image. Creating a memorable souvenir!”
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7. Other unusual visitors
”Another surprising appearance, this time during fieldwork in Gabon. The place where our scanning devices were installed had many fruit trees, where herds of elephants came to eat. You can see from this scan that it was quick, producing a result with much less detail than in the case of the cassowaries. And just in case you were wondering: the scanning lasers we use are completely safe. No animals were harmed in the making of this picture!”
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8. Ghost Trees: scans als basis voor kunst
“Forestry is sometimes described as partly science and partly art. Long ago, I received a message from James McGrath, a painter who became a successful digital artist. Working with sound artist Gary Sinclair, he wanted to use my scans in a work of art. That was the beginning of Ghost Trees. In this immersive sound and image installation, melodious elements are produced from spatial data points, giving the impression that the trees are singing. In this way, Ghost Trees appears to bring the threatened Rushworth Forest in Australia to life.”
“I am a real believer in open science. For every one person who may use your data less appropriately, you have 100 positive experiences. I also hope to team up with a digital artist in Belgium some time. The extra interpretation given to my images by an artist is very inspiring.”
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9. Where it all began
“Hallerbos forest was the very first place where I scanned trees, during my doctorate. I received the key to the forest gate and simply drove my Toyota through the woods, on the tarmac roads, of course! At that moment, the forest was filled with bluebells in flower. These days, if you want to see the bluebells, you can only visit as part of a shuttle bus tour.”
“I’m sure that LiDAR will create lots of opportunities in the future. Imagine the potential for lessons on tropical forestry! You simply pop on some Virtual Reality glasses and go for a virtual stroll through the forest. We’ll be seeing you!”
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