My Favorite Tree: The Bur Oak
- Jason G. Freund
- Jun 29
- 4 min read
Those majestic trees you see standing all alone in the middle of that corn or soybean field, it is probably a Bur Oak (Quercus macrocarpa). They are loners, a characteristic that, at times, I can relate to. They are hardy trees that can survive conditions - in particular, fire - that would kill most trees. I like Bur Oak trees so much, I bought a book with nothing but photos of a single Bur Oak, That Tree.
There are many characteristics of Bur Oaks that draws me to them. They are distinct - that unkempt shape with their seemingly random branches makes them a great shade tree. They're not a riparian tree, but they can live in fairly wet places - though they are also quite tolerant to drought thanks to their deep tap root. Bur Oaks are among the most cold-tolerant of the oaks. As adults, their thick bark has evolved to protect them from fire, and they are among the most fire-resistant of trees. This, as you will see below - makes them a tree of the prairies and savannas. They are survivors. Across the Driftless Area, you can find Bur Oaks that date back to the Civil War. The largest Bur Oak tree in Wisconsin - near Waukesha - dates back to 1771 - over 300 years old. They are one of the slowest growing but longest lived oaks. Live slow, die old - a pretty classic type III species.
Bur Oak - Piiksigu or Mitigomizh in the Ho-Chunk language - played an important food and medicinal role before Europeans arrived to what is now Wisconsin. Their acorns are the largest of the oaks - up to 2 inches long and 1.5 inches wide. Bur Oaks were certainly more common before European settlement. While we often left a lone oak standing here and there, they were certainly more common in the savanna habitats that once made up most of southern Wisconsin but were converted to agricultural fields. (For more on that topic, What Did the Driftless Look Like?)
Bur Oaks are fire-resistant once they reach a dozen or so years old. And we know that the native Ho-Chunk (Wikipedia) people used fire to manage much of the Driftless Area and Wisconsin. These fires likely created an environment where Bur Oaks were able to out-compete, or maybe more accurately, out-survive many of the other tree species. Maybe you too are familiar with a Bur Oak or two that today are in the middle of a wood lot, seemingly out of place. I had a favorite Bur Oak tree growing up that is on the Waterloo Wildlife Area that I often leaned my back against as a deer hunting ground blind. In fact, I can find this tree in 1937 on the Wisconsin Historic Aerial Image Finder. Even at a young age, seeing this species I was familiar with as lone trees in the middle of farmers' fields, I knew this tree began its life in those same open conditions. Bur Oaks are tolerant of much, but they are not tolerant of shading at young ages.
As you can see, Bur Oaks were members of three of the six most common pre-settlement tree communities. They were an important component for tree communities for over a third (35%) of the Driftless Area. Today, they are largely that lone oak you see on plateaus that are much of the agricultural lands of the Driftless Area and, on occasion, in wood lots that grew around those once lone oaks.
As mentioned above, Bur Oaks were once more common than they are today. In fact, in the Driftless Area, along with their other white oak relatives (White Oak, Q. alba and Swamp White Oak, Q. bicolor) have seen the greatest decline in their relative dominance over time. And it is not just the Driftless area, Bur Oak would have been more common in much of the Central Sands as well as other areas with sandy soils that promoted savanna habitats over wood lots (fire probably helped too). Oak regeneration has been a topic of interest for much of the Midwest. We see little Bur Oak regeneration because there is little savanna habitat for them to grow. Many other oaks are unable to survive the intense deer browse. Oak wilt and Bur Oak blight have been significant issues.
That Tree
Mark Hirsch's book about "That Tree", titled, "That Tree (An iPhone Photo Journal Documenting a Year in the Life of a Lonely Bur Oak)", is a great gift for the tree lover. I picked up the book on a whim and break it out at least a couple of times a year to look through the year of a lone oak tree once again. That Tree - a lone Bur Oak tree in the Platteville area - died in a wind storm, a derecho, during COVID times.
While 'That Tree' is no longer standing, it lives on through its offspring and through Mark's gorgeous book and his story.
We have large bur oaks among others on or near our property. We planted 50 small bur oaks, but the deer got most of them. As a favorite broadleaf it's hard to beat the basswood, which will be in bloom soon and will provide nectar to our bees, who will turn it into pale and sweet basswood honey.
I have a small oak that is three seasons old at this point, and I've fenced it off to keep the deer from eating it. How to we tell if it's a burr oak rather than some other type of oak?
Jason, thanks so much for another great post. Bur oaks are also one of my fav trees and several remain on my heavily wooded property (mostly walnut, elm, hickory & red oak), which, according to Finely’s maps, was previously bur oak savannah. I often wonder about those views from my house.