Identifying Water Oak (Quercus nigra)

[WDH]

Water oak is a chameleon.  There are a variety of leaf shapes that are impacted by the age of the plant, whether in shade or sun, the site it is growing on, and just plain water-oak devilishness.  It is a red oak that grows on a very wide diversity of sites.  Sometimes it is good; sometimes it is bad.  Sometimes it is pretty; sometimes it is ugly.  If you just look at the leaves, it can be confusing at first.  The key is to observe the entire plant and look at leaves on several parts of the tree if possible.  The bark varies quite a bit too .

PLEASE NOTE:  Water oak is widely planted as an ornamental.  The pictures and characteristics posted here are not of street trees but of forest trees.  On street trees, the bark can be quite variable, but in general, the overall characteristics covered here are about the same; the street trees are just tamer .

The  Key Characteristics:
 

The Bark:

The bark is generally smooth for a red oak. One of the smoothest in fact.  It is silvery gray most of the time.  It can be rougher and darker, especially on bottomland sites, but for the most part, it is smoother than rougher.  When the bark is rough and furrowed, it is usually only at the lower bole.  It turns gray and proceeds to get smoother as you progress up the bole.

Sometimes the bark shows inconspicuous silver streaking, especially further up the bole.  Sometimes it does not show silver streaking   .

Most of the time the bark smooths up as you go up the bole.  I have seen it smooth almost like beech.  On poor sites, it can be rougher, but rarely as dark and furrowed as southern red oak or black oak. 

The bark commonly displays white blotches or white vertical bands, similar to that seen in southern red oak, but as mentioned before, the bark is generally much smoother than southern red.

The tree is prone to epicormic branching (sprouting from the stem or bole) when the timber stand is opened up by thinning or other disturbance.

The Leaves:

The leaves are highly variable to say the least.  There are at least 4 different leaf shapes.  Young understory water oak shade leaves can fool you .

The prototype leaf you see in all the books is called spatulate in shape.  That is, the leaf is broadest at the tip, sort of like a spatula.  This widening and rounding at the tip is what you typically see in the sun leaves on a mature plant.  Sometimes widening at the tip results in a distinct 3-lobed tip.

Very young plants in the shade will exhibit some rather large leaves that are sometimes lobed like black oak.  Sometimes they are not lobed at all, but long, broad and blunt.  Sometimes they are spatulate, too .

The shade leaves are larger (they can be twice as large as the sun leaves) and the shade leaves are the ones with the most funky variable shapes.   

The sun leaves are more consistently the spatulate shape and more uniform in size.

The leaves have distinct bristles when young.  As they get older, the bristles seem to wear off or diasppear.

The leaf petioles are very short (about 1/4" or less).

The acorn is small.  Water oak can produce prolific crops of acorns that are important as a wildlife food.  It seems to be more consistent in its acorn production that most oaks, so it a good choice for a wildlife food tree.

Bark :

This is the bark of a larger tree on a good site.  Note the camera case for scale.  No prominent silver streaks on the lower bole in this specimen.
 

The upper bole of the tree in the previous pic.  Some minimal streaking.  Notice the white splotches and faint horizontal banding.
 

Here is a specimen with very smooth bark.  Note the white banding:
 

Here is a specimen on a poorer site with darker and rougher bark.  Some silver streaking.  Also note the epicormic branching and the long shade leaves:
 

Specimen displaying epicormic branching, shade leaf shapes, and smooth bark with inconspicuous silver streaking:
 

The Leaves:

Prototype spatula-shaped, widest at the tip, water oak sun leaves.  Some are spatulate, some lobed, some three lobed, etc.
 

Here are some of the highly variable shade leaf shapes.  Young plants display the most varied shapes.  There is less variability in mature plants:
 

Here is a comparison of shade leaves from a young understory plant at the top, more typical shade leaves from a mature plant in the middle, and the prototype spatulate sun leaves from a mature plant at the bottom.  The bottom row is the leaf shape most associated with water oak:



Water oak is not the only oak with spatulate leaves.  Another red oak, blackjack oak (Quercus marylandica) also has the widest at the tip, sometimes 3-lobe spatula shaped leaf that is a dead-ringer for the same shape as water oak.  Fortunately, the blackjack oak leaves are many times larger than water oak leaves.  Blackjack oak on the left and several water oak leaves on the right
 :

[Don K]

Water Oak I am well aquainted with. I think every boy in the South knows what water oak is at a early age. I like to burn it best of all woods in my fireplace. There is nothing better than cutting a light pole straight tree about 14" in dia. that has grown up as a understory tree. No limbs and splits like cutting a pie.

[Lanier_Lurker]

Don, you are right about the water oak as firewood - it is great.  In the area of southwest Georgia I originally hail from they are plentiful.  In that area about the only oak I prefer over water oak for firewood is willow oak.  Of course, live oak is the best, but it is definitely not like cutting pie to split.  Willow oak is comparable to water oak for splitting ease, and seems more dependable for providing long sections without knots or limbs.  But, given the right conditions as you point out, water oak makes a nice straight tree.

WDH, it seems that the life expectancy of water oak is shorter than many other oaks - and I have seen large specimens die and become a deadfall danger for no apparent reason other than simply giving up on life.  Can you tell us more about that?

[WDH]

There is a fungus that causes a disease called Hypoxylon Canker that is killing many oaks.  It is not totally understood, but one way that it is thought to enter the tree is through wounds.  Water oak is such a common ornamental tree that it may be more likely to get wounds due to the association with people.  Or, maybe it is just especially susceptible to the fungus.  In any case, this fungus is the cause of death of many of our oaks.  It seems to really hit water oak and southern red oak hard from my observations.  I also think that drought weakens the oaks, making them more susceptible to infection (but that is just an opinion on my part).

[Don K]

I have seen a good number of large water oaks that have given up the ghost for no apparent reason and where I am from misltoe is a big problem in some trees. That stuff is like a tree cancer. Birds love those berries and they sprout easily.

[WDH]

When I get the chance, I will take a pic of the hypoxolon canker unless someone else already has one to post.

[DWM II]

I think most of the oaks I've been calling pin oaks is water oaks. The silver banding is the give away I think. Not to mention the leaves, I guess its a dead ringer these are water oaks.

[Dodgy Loner]

Nice pictures, especially of the young leaves.  Water oak becomes exponentially easier to identify the older it gets.  I've seen people confuse the young ones with everything from willow and laurel oak to overcup and post oak.

[limbrat]

You aint gona believe this, i aint seen it but once. 
I cut a water oak that had the top broke out were it got about 6" it had a branch on top and some live sap wood. The top 4 or 5' was hollow and full of dottie wood and dirt and it had 4or5 earthworms in it how the worms got in a tree top i have no ideal they were all about the same size.

[WDH]

Maybe the early bird carried them up there .  I have never seen anything like that.

[tcsmpsi]

I think most of the oaks I've been calling pin oaks is water oaks. The silver banding is the give away I think. Not to mention the leaves, I guess its a dead ringer these are water oaks.

The way I had been programmed to identify the pin oak, though the bark, limb arrangement, growth pecularities were similar to some others, is that the pin oak's leaves came to a definitive point.

The reason I kept WDH on the west side of the draw when he came for a visit, is because on the east side, going up the hill, there are some oaks and other hardwood types that have not been forth coming with who they are.   

If we got started with them, we might still be there.   

[WDH]

Looks like I will have to visit them .  I promise that I will be more sensitive this time.  I hope the yaupon family is doing well .

[tcsmpsi]

Looks like I will have to visit them .  I promise that I will be more sensitive this time.  I hope the yaupon family is doing well .

You know the yaupon family.  They take the least little hint as quantum encouragement.     

However, at the present, they are playing second fiddle to the beech.

[DanG]

Tcsmpsi, I'm surprised you would use such a degrading term as "second fiddle" to describe the poor Yaupon family's position in their community.  Wouldn't it be better to say, "The Yaupons are running strong in second place, while the Beeches are struggling along, next to last."?

 

[WDH]

You are right, DanG.  Those yaupons have self-esteem problems.................

[scgargoyle]

You are right, DanG.  Those yaupons have self-esteem problems.................

'Specially the weeping ones...

[Dodgy Loner]

You are right, DanG. Those yaupons have self-esteem problems.................

'Specially the weeping ones...

 

[tcsmpsi]

Tcsmpsi, I'm surprised you would use such a degrading term as "second fiddle" to describe the poor Yaupon family's position in their community.  Wouldn't it be better to say, "The Yaupons are running strong in second place, while the Beeches are struggling along, next to last."?

 

Please, to understand, it was a studied response relying on an extensive culmination of research analyzing the psychological profile of the yaupon, and the ensuing, appropriate application of behavioral modification technique.

                                                     

[scgargoyle]

You'd have issues, too, if your last name was 'Vomitoria'.

[WDH]

Do you know how it got that name?