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  • Writer's pictureJennifer Anderson

Know Your Oaks

Updated: May 8

When kids leave the nest, we parents learn a few things.  In our case:

  • A new indulgence, Bourbon (our son went to Kentucky), and

  • A connection between bourbon and one of my favorite trees, the White Oak (Quercus alba). 

Federal law, it turns out, requires bourbon to mature in barrels made from oak–and it’s definitely White Oak because this tree’s wood is waterproof.   


White Oak?  Is there anything this tree can’t do?   We all now know oak trees feed more caterpillars than any other native plant – more than 500.  


Did we all know even bats love White Oaks?

This love affair has to do with the bark on a mature White Oak attaching to the tree on one side but not on the other. The asymmetry turns out to be perfect nesting habitat for bats – and it makes White Oak one of the few hardwoods in North America capable of providing roosting habitat while still alive (Davis, R.).



If you are a bat lover that may be reason enough to choose a White Oak. But for the rest of us there may be other reasons for choosing one oak versus another.


In North America, there are about 90 Oak species, and generally they fall into one of two groups, with a few examples of each below.  


  • Group 1: The White Oaks generally have whitish heartwood and leaves with rounded lobes. 


White Oak (Quercus alba) is one of the biggest of the oaks, and indeed of all Eastern natives, achieving heights of 50 to 80 feet and a huge, spreading crown – the quintessential lone tree with twisting branches silhouetted in an old field.


White Oak’s spring leaves are pinkish, and fall color often looks like red wine.


White Oak does not respond well to urban stresses, but it may look great in your yard.  I planted two on my quarter acre :).  These trees also have deep tap roots and don’t like to be moved, so choose your spot carefully.


Bur Oak, also called Mossy-cup Oak because of the fringe along the cap of the acorn, is one of the biggest in the group and needs a large area to grow and expand.  


It is adaptable to most soil conditions and urban sites, but it is most commonly associated with the tall-grass prairies.  


Fun fact:  As the prairies burn, the Bur Oak seedlings die back over and over, forming an underground burl.  This confused settlers attempting to remove seedlings and finding instead a gigantic root. (Cullina, W.)



Swamp White Oak tops out at just 50 to 60 feet with a similar spread, but it grows a little faster – two appealing features that may explain why I see more Swamp than White oak on my dog walks.


Swamp White Oak has a classic big, round crown and short, stout trunk.  It is named after the two-toned leaves, dark green above and whitish underneath.  These leaves turn a bronzy-brownish color in fall, sometimes with a tint of yellow.


Swamp White Oak makes a great specimen or shade tree, and its roots are fibrous and relatively easy to transplant.  It likes areas that tend to be moist in the spring and drier in summer.


  • Group 2: The Red Oaks are coveted for their beautiful red heartwood and can be identified by the points on their lobes.


Northern Red Oak (Quercus rubra) is among the fastest growing, reaching heights of 60 to 75 feet with a similar branch spread and rounded, irregular crown.  


Its bark makes it easy to identify.  As the tree ages, its ridges become smooth and flatten out, kind of like trails on a ski mountain.   Pinkish lines also can be seen underneath the bark.


Northern Red Oak is easy to transplant; it prefers dry sites and well-drained soils, and it tolerates urban pollution.  Fall color can be brownish to bright red.  


Fun fact: Northern Red Oak is the state tree of New Jersey and the provincial tree of Prince Edward Island.

Pin Oak (Quercus palustris) is one of the fastest growing oaks and is narrower than the others with a single, straight trunk, making it perhaps the most popular of the oaks.


It gets about 60 to 70 feet tall and spreads about 40 feet wide.  Its fall color is a nice bronzy red.


Pin Oak shares similarities with Swamp White Oak in that both prefer bottomlands and tolerate occasional flooding.  They also both have root systems that make them easier to transplant and more likely to be available at nurseries.


Pin Oak makes a beautiful shade and street tree, and it is a common sight in parks and neighborhoods.  Its branching–lower turned down, middle spreading horizontally and upper angling upward–adds to its appeal.


Often confused with Pin Oak is the less-common Scarlet Oak (Quercus coccinea), although there are critical differences.


Scarlet Oak is an upland species, preferring dry sites and soils with good drainage. 


Scarlet Oak can get 70 to 75 feet tall, and its broad branching starts low and can spread 40 feet or more. 


It is best known and coveted for its brilliant scarlet late-fall foliage.


Interestingly, mature Scarlet Oaks can experience swelling caused by the same fungus that obliterated the American Chestnut, Castanea dentata.  In the oak, though, the fungus rarely kills the tree (University of Kentucky).


Fun fact: Scarlet Oak is the tree of the District of Columbia.


 

The Mother Oak

I suspect my bias toward the White Oak stems from a quick stop my husband and I made about 25 years ago to see the old Wye Oak, a long-term resident of Talbot County, Md.  


The late-Oak, an inductee into American Forestry Magazine’s Tree Hall of Fame, was believed to have been the country’s largest Oak, at 96 feet tall and almost 32 feet around.  It also broke the scale at an estimated 60,000 pounds – about the size of a humpback whale.


After a long life that began in the 1500s, a thunderstorm in 2002 finally brought down the old Wye Oak.


 

Final fun fact: In 2004, the oak was officially declared the National Tree of the United States, symbolizing the nation's strength. 


 

About the author:

Jennifer Anderson is the owner of Tree Talk Natives, a native tree and plant nursery in Rochester, Mass. She loves to talk native plants and can be reached at jennifer@treetalknatives.com.




 

Sources:


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2 Comments


dgreene
May 06

I love bats, so it's good to know that they like White Oak for roosting! Thank you for these blog posts. I'm a native plant novice and learn so much from them.

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Jennifer Anderson
Jennifer Anderson
May 13
Replying to

My pleasure! Thank you so much for your comment. I love writing these blogs.

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