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The Olympics of Trees: Searching for the Largest and the Oldest Trees

Updated: Apr 29, 2022

While you may have been following the recent winter Olympics that happens every 4 years, for some who like to chase other records the season never ends. It is the search for the biggest tree, the Olympics of trees!

For trees there are records for girth (circumference), crown dimension, height and then combining these dimensions into one number to determine a champion tree. Some even keep records of the oldest of trees. There is a lot that goes in to finding a champion tree. It not only takes a lot of searching but also a bit of math. The trees don’t always cooperate either. They can be in difficult to access areas, on difficult slopes, surrounded by other trees that block your measurements, and their form may not lend itself to a simple geometric measure. That said, from the little experience I have had doing it, searching and measuring for big trees is an enjoyable and interesting experience. And one you can do all year.

Once you know the diameter of a tree you can also estimate its age. The circumference (girth) of a tree divided by pi (3.14) equals its diameter. The diameter in inches is then multiplied by a factor specific for the tree species to give you the trees estimated age. This may be more accurate for forest grown trees and might over-estimate the age of a tree growing in ideal conditions. I will put the directions for measuring circumference, tree height, diameter and even crown spread at the end of this blog. All it really takes is a measuring tape and a stick! But you can get more expensive tools and use an app for your smartphone and/or a laser rangefinder. No matter what you use it can be difficult to get an accurate sighting for height due to uneven ground and obstructions from other trees and objects. To make things simple at the start, my measurements of the biggest trees will include only circumference. We can start measuring height and crown spread if we truly think we have a monster.

Each species of tree has its own champion tree. The largest and perhaps oldest Bur Oak in Wisconsin resides on Stonefence Farm in Waukesha.

She is about 315 years old and has a diameter of 7 feet. Quite a tree.

So the question is: Where is the biggest tree in our Bluffland’s Olympics? and Do we have oaks or other trees that can approach the champion gold medal size?

I started my quest in the Dobson Blufflands Tract. Shortly before it was acquired for public enjoyment about 15 years ago it was logged and most of its big trees were taken out. The largest Bur Oak in the Dobson Tract I could find was 60 inches in circumference, a diameter of 19 inches, giving it an estimated age of 95 years. Not bad but definitely not close to the Queen of Stonefence Farm. So there is a good chance there is a bigger one somewhere in the Blufflands.

Above: The largest Bur Oak in Dobson Blufflands. 60 inch circum.

Dobson does have a couple nice size White Pines, one with a 74 inch circumference, 23.6 inch diameter, and an estimated age of 118 years.

Take a hike or a bike on the trails at the National Weather Station and near Thompson Prairie and you can find some large oaks lining the trail.

This Red Oak in the foreground is 98 inches in circumference. That makes its diameter 31.2 inches and its age about 125 years old. That is leading the gold medal race as the biggest Red Oak I’ve found so far. But there may be some 40 inch diameter Red Oaks out there somewhere.

This White Oak is leading for the biggest circumference at 95 inches and a 30.2 inch diameter for an estimated age of 151 years. However there is a White Oak close by that might beat it if the crown dimensions were factored into the total score:

The White Oak above was hard to get into a picture due to its great spreading limbs extending over the trail. It has a circumference of 88 inches which is large but not as big as our first offering. However, this one likely grew up in the open savanna. It could therefore stretch its limbs out as it grew and so has a much larger crown dimension.

There are some large Cottonwoods in the state. The one taking the gold so far is in Dodge County measuring 360 inches in circumference.

As for the Blufflands?: I found a few large Cottonwoods near the Lower Hixon parking lot. The leader after the first round is one along the golf course road measuring 220 inches in circumference. For the record if the Cottonwood that is now Pooh’s Lair near the parking lot were still alive it would have measured about 266 inches in circumference – quite a specimen! I wonder if the Friends of La Crosse Marsh can beat that with some of their Cottonwoods.

A large Cottonwood near the Lower Hixon parking lot.

So if this has got you interested in looking in the Blufflands for your gold medal tree I have put some links to directions for measuring trees and some guidelines here. In addition there are apps you can get for your smartphone that will measure the trees height for you. One app called Globe Observer by NASA is free and fairly easy to use. After you find the tree’s diameter you can estimate its age by using the attached chart.

This is a free handbook you can download or order:

This is a link to Wisconsin DNR’s site about measuring and nominating a champion tree:

There are apps including Globe Observer for measuring tree height and other.

Here are a few summary instructions for measuring circumference and height. I also included a chart that you can use to give you a rough estimate of a tree’s age.


So get out there and find your gold medal tree! While you’re out there you might see some of your fellow Friends of the Blufflands helping to preserve and restore the land for these beautiful trees.

See you out there!

Mike O’Brien

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Hi Mike,

Very interesting article, especially since I'm reading The Wild Trees right now, about huge redwoods and Douglas-firs in the Pacific Northwest. These are so tall (the redwoods over 300 feet) and close together that one can't see the tops from the ground.

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