Documenting our Giants
creating A Digital Database of South Africa’s Living Heritage
From Pretoria’s sidewalks to the vastness of our National Parks, we are mapping the giants that define our landscape.
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Submit your favourite Tshwane big tree today!
You can share your tree with us in two easy ways. An Online Form: quick and simple, fill it out using the link below. Or use the Word Form: download, complete, and email it back to us.
A winning shepherds tree in Kgalagadi National Park. Photo by Waldie le Grange.
Our Mission
The Big Trees of South Africa project is a collaborative initiative dedicated to the scientific measurement and documentation of our country’s most significant botanical specimens. Launched by Waldie le Grange, we utilise precise measurement formulas to record tree height, crown spread, and stem circumference. Our goal is to create a living digital record that serves researchers, conservationists, and nature enthusiasts alike, ensuring these ancient giants are recognized and preserved for future generations.
The Importance of the Record
Beyond the Numbers
Why we document South Africa’s Giants
A measurement is more than just a data point; it is a snapshot of our natural history. By documenting these trees, we are:
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Securing Protection: Providing the scientific data required to declare trees as protected “Champion Trees” in Southern Africa.
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Monitoring Change: Creating a baseline to study the effects of climate and urban development over decades.
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Preserving Heritage: Mapping the “silent witnesses” that have stood through centuries of Southern African history.
Our Primary Projects
Explore the initiatives mapping the botanical giants of Southern Africa.
Big Trees of Tshwane
Identifying the giants in our capital’s historic urban forest.
Big Trees of SANPARKS
Scientific survey across 19 National Parks to identify national champions.
Big Trees of Namibia
Expanding our borders to document the giants of the desert and savanna.
Champion trees of SA
Official government-protected botanical monuments.
National register of big trees
Biggest tree of each species.
The Science of Giants
How We Measure
How we calculate the Size Index (SI)
To move beyond “it looks big” to a scientific record, we use a standardised formula to calculate a tree’s Size Index. This allows us to compare different species—like a soaring Eucalyptus and a massive Baobab—accurately.
We record three vital measurements:
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Trunk Diameter (d): Measured at 1.3m (Breast Height).
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Tree Height (h): The vertical distance from the ground to the highest living point.
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Average Crown Spread (2r): The average width of the canopy, measured across North-South and East-West axes.
By combining these into our formula, we create an objective ranking for every giant in our database.
Interactive SI Calculator
Think you’ve found a contender? Enter the measurements below to calculate the Size Index instantly.
Note: For official recording, our team will verify these measurements with professional equipment.
Scientific SI Calculator
Get Involved
Become a Tree Scout
Calling all amateur botanists, citizen scientists and residents! You don’t need to be a professional botanist to help. Most of South Africa’s most significant trees are hiding in plain sight. Whether you are walking your dog in Pretoria or on a game drive in Kruger, you can be a “Tree Scout.”
Use the GISS method (General Impression of Size and Shape) to spot unique trees in your area. If a tree stands out from its surroundings because it looks exceptionally tall, wide, or historically significant, it’s worth a second look. Every submission helps us map our urban forest, identify candidate trees for protection, and build a natural legacy for our country.
How to Scout Trees:
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Spot it: Look for trees that grab your attention. Is it the tallest on the block? Does it have a massive trunk or a legendary story?
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Snap it: Take a clear photo. You can use apps like iNaturalist to help identify the species if you’re unsure.
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Log it: Use Magalies Dendro’s Submission Form to send us the GPS coordinates and photos.
Don’t worry about the maths—we’ll take care of the measuring tape and clinometer!
“What is the good of your stars and trees, your sunrise and the wind, if they do not enter into our daily lives?”
Explore Our Latest Blog Posts
Our Collaborators
Our Sponsors
Recognising the essential contributions of our volunteer community
Waldie le Grange
Phia le Grange
Susan Grabe
Willem Steenkamp
Joan Greeff
Marissa Greeff
Carol Steenkamp
Retha Prinsloo