What do tree surgeons do on their day off?

Don’t miss the post Hanging about in the tree tops which is about the 2013 Explore: The Ancient Trees of Africa expedition.

So what do tree surgeons (or arborists to give them their official job title) do on their day off? Well, if you’re these tree surgeons you go climbing trees. Not just any old trees mind, very big ones! They are also not just doing it for fun, but to measure the accurate height of these very tall Karri gum (Eucalyptus diversicolor) trees, which were planted in 1926. This was done for the South African Champion Tree Project, part of which is to determine the heights of the largest trees in South Africa.

An edited quote from Leon Visser (on the right in the photograph below):

The grove at Brackenhill is phenomenal in its own right, and it was a great privilege to be able to climb and measure them.

This is the first ascent of these giant trees and whereas the previous height was given as 68m (223.1 feet), I measured them at 71.5m (234.5 feet).

This is the 3rd highest tree I have climbed, the tallest being the gums in Magoebaskloof which are 78.5 (257.5 feet) and 79m (259.1 feet) – the tallest measured trees in Africa and as far as we know the tallest PLANTED gums in the world.

[Click on photographs to enlarge them]

Can you see the climber sitting on a branch in the centre tree below?

To climb the trees, one needs mountain climbing gear, a very big catapult, lots of rope, a long tape measure and measuring stick or pole. Oh, and of course, people with serious climbing skills! [Note: this should only be done by professionals – do not try this at home!].

Photo above: Leon Visser

While there are more modern techniques of tree height measurement involving the use of electronic gadgets like tree height meters or hypsometers, these are not accurate enough when measuring trees which have a rounded crown, or trees which are leaning slightly. Hypsometers rely on the use of trigonometry and triangulation to calculate the height of the tree. So if you cannot accurately determine the highest point of the tree, the calculation will be inaccurate. To see how the measurements using a hypsometer are done click here. To read the guidelines of measuring a Champion (or Big) tree click here.

Photo above: Leon Visser

To begin with the climbers shoot the first rope up as high as they can using the big catapult. And then the climbing begins. In this case, the climbers could not secure the first rope on the tree they wanted to climb (because the lowest branches were too thin to take their weight), so one climber had to climb the adjacent tree, and then winch himself over to the “right” tree.

Then it was a slow and careful climb up and up . . .

Once one of the climbers is as far up the tree as he can go, he uses a measuring rod to find the distance from his height on the tree, to the very top of the tree. Then a measuring tape is dropped to measure the height down to the ground. The two measurements are added to get the final and accurate tree height.

To give you some idea of just how high 71.5m (233 feet) is, take a look at the series of photos below. In the first photograph look at the little white spot below the red arrow. That is the top climber’s torso! The climbers are obviously not scared of heights.

Zooming in a little further, the red arrow still marks the spot.

And zooming in even more . . . now one can make out a human form.

And finally came the careful descent back down to the ground. The whole process from the beginning of the climb, to getting safely back on the ground took about 4 hours. One tree was measured.

Photo above: Leon Visser

Credits: Photographs: Willie (WMB) unless otherwise stated; Information: Willie; Photo processing and text: Lisa @ Notes from Africa | Photoblog


About lisa@notesfromafrica

I live on the Southern coast of South Africa, and write about the things that interest, amuse or inspire me. You can find me at http://notesfromafrica.wordpress.com and https://southerncape.wordpress.com (my photoblog)
This entry was posted in Nature ● Environment, Photography and tagged , , , , , . Bookmark the permalink.

23 Responses to What do tree surgeons do on their day off?

  1. Sarita Botha says:

    Wow! That is incredible.

    I can think of other things to do on my day off!!!

  2. This is a very interesting post. I’m a big fan of trees, and I’m always sad when they (have to) get cut down (“felled”?). A few months back I drove past a small plantation of very young trees – a lovely sight – but I never thought about the older, bigger trees being measured. That is quite an exercise. I bet it beats going to the gym 😉

  3. Absolutely incredible, Lisa–stunning photos. Those trees are ENORMOUS! And again–I love the title of this post.

    By the way, I love your idea about sharing news updates in my blog. I will begin doing that later this week, after a couple of posts I already have planned around the 1 year anniversary of the earthquake which is Wed–12 January.

  4. bagnidilucca says:

    You wouldn’t want to have a fear of heights. We have Karri trees in Australia as well – Western Australia I think. Mind you we need a few here in Queensland just now to get away from the water. I did a short post on the water situation near my home a couple of hours ago. http://bagnidilucca.wordpress.com

  5. Slowvelder says:

    Wow – awesome post! I would love to have watched the process. Beats climbing mountains anyday. Those trees are about 28 stories high – incredible!

  6. hemlock1981 says:

    Wow. What an awesome capture.

    The job looks fun, even though it is dangerous. I agree, only those that know what they are doing should do this.

  7. Estie says:

    wow. That was very interesting. Congrats on the great blog.

  8. Whoa! That is a heck of a job. I can picture it at a dinner party… “What do you do?” “Oh, I measure how tall trees are.” “Doesn’t it get a bit boring?” “Hmmm… nah.”

  9. Reggie says:

    Wow. Wow. Wow. I so wish I did not have a fear of heights… this would be awesome!

  10. Jacques says:

    I’ve recently adde a Geocache near the trees and had several visits there already. I spoke to Leon Visser for more info but would also like to post a picture or two of the actual measuring of the trees, especially the side views of the person up in the branches to give same idea of scale. It will be listed under my caches at http://www.geocaching.com.

    Here is my listing to it. http://www.geocaching.com/seek/cache_details.aspx?guid=5a243bc7-434c-42e6-a6e1-b42f28bc2ebe

    Please let me know if it will be ok to use the pictures.
    Thank you
    Jacques Bayman

  11. Pingback: Weekly Photo Challenge: Up | Notes from Africa

  12. johnnys088 says:

    Great pictures! I have noticed that the Arborists in Sydney that are good climbers always have work and are paid better. It is dangerous but with the right equipment it can be fun!

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