Black Scarlet and Northern Pin Oaks

Black, Scarlet, and Northern Pin Oaks	March 26, 2008
	Doug Bidlack

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TOPIC: Black, scarlet and northern pin (Hill's) oak
http://groups.google.com/group/entstrees/browse_thread/thread/f20b624c9d465bf8?hl=en
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ENTS,

these three species have interested me for a number of
years because of the great difficulty in telling them
apart from one another. They also happen to all occur
in southeastern Michigan, particularly in Oakland
County where I grew up. Northwestern Indiana /
northeastern Illinois is also supposed to be a great
place to find all three together.

The fairly recent posts by Beth, Lee and Bob have
prompted me to add my two cents worth that I've picked
up over the years. I've been a bit slow to respond
because of a new computer and my attempt to add a link
to some photos of these three species...I sure hope it
works!

I'll start with how to tell them apart.

Bark: I can't tell them apart on youngsters, but when
they get older black oak seems to have the thickest,
most deeply furrowed bark. In the classic example of
black oak, at least for me, it is often very blocky in
appearance. Hill's oak (northern pin oak) has thin,
shallowly furrowed bark. It often looks like someone
flattened the ridges into plates by pounding on them.
Scarlet oak bark usually seems to be intermediate
between black and Hill's oak. Oh, from now on I'll
refer to northern pin oak as Hill's oak. I think I
started doing this because the folks at the
International Oak Society seem to prefer this common
name. I don't know why they prefer this name, but I
like it because Hill's oak is more like black and
scarlet oak than pin oak (Q. palustris) and it also is
found in dry soil regions rather than the floodplain
areas where pin oak occurs. I also like the shorter
name.

Leaves: Black oak has the largest leaves (10-20cm
long) with the shallowest lobes and Hill's oak has the
smallest leaves (7-13cm long) and perhaps the most
deeply lobed. Scarlet oak is again in the middle, but
much more like Hill's oak (8-15cm long). Black oak
leaves turn some shade of brown in fall while scarlet
oak leaves turn some shade of red in fall. Hill's oak
can have leaves that turn brown, red or anywhere in
between in fall.

Winter buds: Black oaks have the largest terminal
buds (6-12mm long) and they are ovoid to conical and
hoary-tomentose. Hill's oak has the smallest terminal
buds (3-5mm long) and they are 5-angled in cross
section and usually pubescent only toward the apex.
Scarlet oaks are very similar to Hill's oak but the
terminal buds are a little larger (4-7mm long).

Fruit: Black oak acorns are about 1.2 to 1.8cm long
and the cup has loosely fitting scales that form a
slight fringe. Hill's oak acorns are about the same
size, but the cup scales are closely appressed and
they don't form a fringe at the margin. The nuts are
also often ellipsoid in shape and they sometimes have
vertical stripes. Scarlet oak acorns are like Hill's
oak acorns except that they are a little larger (1.3
to 2.2cm long) and the nuts are not ellipsoidal.
Scarlet oak acorns also often have faint concentric
rings near the apex.

Andrew Hipp and Jaime Weber published a paper in the
Proceedings of the Fifth International Oak Conference,
Fall 2006. The title was "Taxonomy of Hill's Oak
(Quercus ellipsoidalis E.J. Hill) in the Chicago
Region: Preliminary Molecular Evidence". They found
that "Scarlet oak, Hill's oak, and black oak can be
distinguished from one another using molecular genetic
data" and that "Hill's oak and scarlet oak are
taxonomically distinct, not simply regional variants
of a single, widespread species". They also found
that "Black oak and Hill's oak are less distinct from
one another than either is from scarlet oak". This is
a little surprising, since Hill's oak appears to be
more similar to scarlet oak morphologically.

Andrew Hipp was the person that really helped me to
understand the best characters for distinguishing
black oak from the other two. Winter buds are
definately the best and the slightly fringed acorn
cups are next best. The difference between scarlet
oak and Hill's oak is more subtle. Scarlet oak has
slightly larger leaves, acorns and winter buds. In
addition, the nuts of Hill's oak are often ellipsoid
and, at least in Oakland County, Michigan, the leaves
generally do not turn bright red (I don't think this
is true for most other regions). Scarlet oak acorns
also often have concentric rings near the apex. One
more character that I didn't mention above is that
Hill's oak often have many persistent dead branches on
the lower trunk.

I have a link to 20 pictures of these three species
that I took in the Kensington Metropark / Milford,
Michigan area.

http://picasaweb.google.com/d.e.bidlack/DryRedOaks

A couple notes about some of these pictures.

Black oak #2 and Hill's oak #1 are a stones throw from
one another and wonderfully easy to separate from one
another (great representatives of their respective
species).

Hill's oak #3 is fatter than the Michigan champion for
this species, but I'm not entirely certain that it is
isn't a black oak. The bark is unusually thick and
deeply furrowed for Hill's oak, but then again I've
never seen one so big around! Almost all the oaks in
the vicinity are Hill's oak. I'll have to go back and
check the winter buds and acorns sometime to verify
that this is indeed Hill's oak. As for the current
Michigan champion, it is supposed to be located in
Oakland County but I was unable to locate it last year
in November.

Scarlet oak #2 could be Hill's oak, but the leaves are
on the large side and I've never seen a Hill's oak
with leaves so red in Kensington Metropark. The tree
appears to be too young to be producing acorns yet.
The leaves are a dead ringer for scarlet oak here in
southeastern Massachusetts, but then again I've seen
plenty of pictures of the leaves of Hill's oak in
other areas that might fit those in this picture.

Doug

== 1 of 1 ==
Date: Thurs, Mar 27 2008 9:52 am
From: Don Staples

Add to that, oaks may have a variety of leaf shapes within the crown
of the tree. In the south, one may have to go to the upper crown,
with full sun exposure, to find a typical species leaf.

== 2 of 8 ==
Date: Fri, Mar 28 2008 9:07 am
From: doug bidlack

Don,

this is why I try to get pictures of leaves from open
grown oaks where they get plenty of sunlight. I've
been trying to ID these three species based on bark
and tree form so I can measure forest grown trees in
winter. I'm not having much luck though. If I can
find acorns it really helps. The more I study these
trees the better I get at identifying them, but it
sure is a slow process.

Doug

== 3 of 8 ==
Date: Fri, Mar 28 2008 12:49 pm
From: Andrew Joslin

Northern Red Oak is very familiar to me, it's the most common oak species
in the woods in eastern Massachusetts and its signature form and bark is
recognized like an old friend in any season. Likewise for Northern Pin
Oak. Black Oak also has distinctive crown form and bark texture. The
mystery to me is Scarlet Oak. Of the 3 oak that I mentioned which is
scarlet most similar to in form? Or would you say that scarlet has its
own signature look?
Here's a nice 44.6" dbh Red Oak to enjoy while you're thinking about
oak ID:

http://tinyurl.com/yuxm82
Looking up at the crown:

http://tinyurl.com/264zv2
Thanks,

Andrew Joslin
Jamaica Plain, MA

== 4 of 8 ==
Date: Fri, Mar 28 2008 12:40 pm
From: dbhguru@comcast.net

Andrew,

I was surprised to learn of the Northern Pin Oak (Quercus ellipsoidalis) in your area. Everything over here in western Mass is Quercus palustris and there are some beauties. I measured one yesterday in Amherst. It was on private property so I didn't try to measure its girth, but I judge it to be at least 11 feet. Its height is around on 104 feet. Beauty.

Bob

== 5 of 8 ==
Date: Fri, Mar 28 2008 1:05 pm
From: doug bidlack

Andrew,

I have a tough time telling these trees apart based on
form. I tried to distinguish between northern red
oak, black oak and Hill's oak (northern pin oak) in
Kensington Metropark based only on bark and tree form.
I failed miserably. I could usually ID northern red
oak because of it's bark and more open form (larger
limbs and less twiggy), but I couldn't reliably
distinguish between black oak and Hill's oak. Scarlet
oak is quite rare in Kensington Metropark, but it is
super common here in southeastern Massachusetts. I
think it looks most like Hill's oak and then probably
black oak. It is, I think, somewhat intermediate in
form between black oak and northern red oak. It also
seems to be somewhat intermediate in terms of soil
moisture. Black oak driest, northern red oak wettest
and scarlet oak in between (though I think it tends to
be more associated with dry soils). In my backyard
and neighborhood (Dighton, MA), scarlet oak is the
dominant oak and we have heavy, clay loam soils that
are only 2 to 4 feet deep before you run into solid
clay. This really surprised me when we first moved
here because I thought scarlet oak only grew in really
well drained soil.

You mention that you are familiar with northern pin
oak here in Massachusetts. I think you must mean pin
oak (Quercus palustris), because northern pin oak =
Hill's oak (Quercus ellipsoidalis) is only supposed to
grow as far east as Ohio and southern Ontario.

I just took some pictures of a scarlet oak in my
backyard last weekend. I'll try and post these two
pictures soon.

Doug

== 6 of 8 ==
Date: Fri, Mar 28 2008 2:33 pm
From: Andrew Joslin

I don't know what the history is for pin oak in eastern Mass., most of
the big ones I've seen are planted along the parkways and in the parks of
Boston. I don't see them in "natural" woods. I guess palustris
must be in the mix, I'm just not seeing it. Perhaps I've misidentified
some palustris as rubra. I'll have to get out to western Mass. to observe
palustris in it's natural habitat.
-Andrew

== 7 of 8 ==
Date: Fri, Mar 28 2008 2:44 pm
From: Andrew Joslin

Oops, I see I'm totally confused.

Palustris is "Pin Oak", got it.

Northern Pin Oak (ellipsoidalis) is not likely found in eastern Mass.
or Massachusetts at all

Scarlet Oak is apparently common in eastern Mass., now I have to go
out and find one so I can get to know it.

Thanks!
-Andrew

== 8 of 8 ==
Date: Fri, Mar 28 2008 2:10 pm
From: doug bidlack

Andrew,

Mt. Auburn Cemetery has a nice big scarlet oak. They
claim it is the largest in Massachusetts. I'm not
sure this is true, but they have a map of all the big
trees in the cemetery. I wonder who measured these
trees and if the heights are accurate?

If you really want to see lots of scarlet oaks
sometime, just come on down here to Dighton. I can
show you some places where scarlet oak are as common
as dirt.

Doug

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