Identifying Tree-of-Heaven and Some Native Look-a-Likes
This presentation will help residents learn to identify tree-of-heaven and distinguish it from some native look-a-likes.
- [Presenter] Hi folks, my name is Dave Jackson and I'm a Forest Resource educator with Penn State Extension out of the Center Counter office.
I've been with Penn State about 15 years now and I work with private forest landowners, forest industry as well as youth.
Today we're gonna talk to you about a topic I've been working on for most of my career with Penn State.
And that is Tree-of-Heaven.
We're gonna teach you how to identify Tree-of-Heaven as well as how to distinguish it from some native look-a-likes.
Let's go ahead and get started.
First we want to give you some background information.
Tree-of-Heaven, its scientific name is Ailanthus altissima.
A lot of folks simply refer to this tree as Ailanthus, however some other common names you might hear it referred to as are Chinese or stinking sumac.
The tree is native to China but it was introduced into our state, into the Philadelphia area by a gardener back in the late 1700s.
This tree was valued as a street and shade tree because of its tolerance to urban conditions.
It was widely planted through the Baltimore and DC area, even into the 20th century.
The tree now occurs in 42 states and is quite common through the Mid-Atlantic region.
We now find it from Maine to Florida and west to California.
It was ultimately introduced into California by Chinese immigrants.
The Tree-of-Heaven can grow into a very large tree.
80 to 100 feet in height and six feet in diameter.
This is a picture of a tree with a colleague of mine by the name of Art Gover, that was growing in an arboretum down in the Pittsburgh area.
And this is another colleague of mine on a forest grown tree, that was outside of Altoona, Pennsylvania.
However the tree is relatively short lived, and trees 50 years of age would be an old tree.
One of the best distinguishing characteristics for Tree-of-Heaven is to look at the leaves.
They have what are referred to as pinnately compound leaves.
Let me define that for you.
So a pinnately compound leaf is what you see here.
They have a central stem called a rachis with leaflets coming off the sides here.
This particular leaf here has 30 leaflets and you can see they're quite long.
This is a yard stick so this leaf is over three feet long.
So the leaves will commonly range from one to four feet in length and can have up to 40 different leaflets on them.
One of the real distinguishing characteristics on these leaves is that they have a smooth margin or edge to the leaf.
So this is the edge of the leaf right here where my pointer is and you can see that it is smooth.
However one of the things that are really distinguishing and a key characteristic is what I have circled here and at the base of the leaves they have these individual teeth.
So you might see one like we have here or you might even see two teeth at the base of the leaf.
That's something to really keep in mind when looking at the leaves of Tree-of-Heaven that will distinguish it from other native look-a-likes.
Also if you were to crush this foliage you would find a strong offensive odor.
Some people liken it to the smell of cat urine or they say burnt peanut butter.
So I've never smelled burnt peanut butter but I can only imagine what it would smell like.
When looking at the bark I have read and some people describe it as resembling a cantelope and I think you can tell that quite easily from this image over here on the right, it actually does resemble the skin of a cantelope.
However it can range in color and you see some twigs in the background here from this reddish brown on some of these younger stems and as it gets older as you saw in the first slide there with the large tree, that light gray-brown color that it'll turn into.
When looking at the twigs they're alternate branched on the stems, versus opposite, they alternate on the stem.
They're smooth, so we don't find any hairs on the stems and they're very stout and blunt.
If you look at the tip here you'll see also that there's no terminal bud at the end here, so there's no bud that you see at the end of the twig.
They range in color from this greenish that we have here to reddish-brown even.
A real key distinguishing characteristic is where we look at the leaf scar.
The leaf scar is what we have pictures here and this is where the leaf was attached to the twig and where it came off last fall.
So right at the top of the leaf scar we'll bind the bud, but the leaf scar has this distinguishing shape, very large, but it has a V or heart shape to it.
If we were to break one of these twigs open or cut them open like I did here in this lower-right image you would also see the center, which is called the pith, is brown and very spongy in texture.
That's another real key distinguishing characteristic for Tree-of-Heaven.
If we were to look at the seeds here they have what they call a samara, which is a winged seed and you can see that down here.
Each of these wings are about two inches in length and contain a single seed in them.
The seeds can remain on the tree throughout the winter and this is an image that I took and you can see how many seeds here, in the upper-right, how many seeds are still hanging on the tree.
This was in late winter that this image was taken.
Interesting to note that they have male and female trees.
So that's what is referred to as dioecious and so you will have separate male and female trees.
And of course the female trees are the trees that will produce the seed.
So the female trees can produce upwards of 300,000 seeds annually.
And if you look at the image in the upper-right here that's my hand in an area that has just completely regenerated with Tree-of-Heaven seedlings.
There are literally thousands of seedlings per acre there.
The other way that this tree spreads is by root suckers and it can send up root suckers upwards of 50 feet away from the parent tree.
And that's what we show in the image here in the lower-right.
This is a parent Tree-of-Heaven and each of these little shoots that you see spreading across the ground here are attached to its root system.
So these are suckers coming off that parent tree's root system.
Another thing that's important to note about Tree-of-Heaven is that it's what is referred to as allelopathic.
This means that the root systems produce a toxin that can inhibit the growth of other plants around it.
And this is a way that this tree can be very successful in taking over new areas.
The tree is very common on disturbed sites and we also often find it growing on forest edges, fields and roadsides.
It's intolerant of shade so it does need sunlight to grow and it cannot compete successfully under closed forest canopies.
So following disturbances, from storms or insect defoliation's or even timber harvesting operations, we often find it coming into those areas.
It can create a dense canopy like you see in the image in the upper-right here from the forest floor right through to the upper canopy.
It will grow in a wide variety of soils.
This is an image that I took here in the lower-right of one that germinated in a sidewalk crack outside of our storage unit here at the office.
But they can grow on very poor soils and we often find them growing on mine spoils and that's why we see them so commonly along roadsides that are rocky, poor soils.
But you'll also find it growing on alluvial soils along stream bottoms and creeks and things like that as well.
So some of the common look-a-likes that this tree can be confused with will all have the similar leaf pattern.
So that pinnately compound leaf and this is a short list of some of the common species that we might encounter with that characteristic.
So Sumac, a couple different kinds of Sumac.
Staghorn or Smooth Sumac.
Walnut, Black Walnut and Butternut or White Walnut, some people refer to.
Hickory, lots of different smooth-barked Hickory's, from Bitternut, to Mocker nut to Pignut could be confused with Tree-of-Heaven.
Ash, both green or white Ash.
And lastly I list Boxelder which is in the Maple family.
All of these have that pinnately compound leaf with leaflets.
However we're gonna just focus, for today's presentation, on just two species that are most commonly confused with it.
And also have been found to be preferred by the Spotted Lantern fly.
So we're gonna focus in on Staghorn Sumac as well as Black Walnut.
So let's look at Staghorn Sumac first and again this has that pinnately compound leaf, so as we look over here to the right it has that central stem or rachis with leaflets.
The leaf itself is this whole unit here and it can range anywhere from 16 to 24 inches long.
So quite a bit shorter than what we see with Tree-of-Heaven which can be upwards of four feet long.
But the real distinguishing characteristic here is that the margin or the edge of the leaf is toothed, or serrated.
So you can see here the little serrations or teeth along the edges of the leaf margin and that's a real distinguishing characteristic.
Then next let's look at the fruit here in the lower-left image.
So the fruit is a red, fuzzy drupe and it persists in these upright clusters.
So the fruit is simply these small structures down here that you see in the image.
A drupe is a fruit that's similar to something like a plum or a cherry, so there's actually a hard seed inside this fuzzy structure here.
But these will persist in these upright clusters and you'll see them on the Staghorn Sumac throughout the winter months so easy to distinguish them.
Second let's look at the twigs here.
The twigs on a Staghorn Sumac, of course where it gets its name, is that they are very fuzzy, similar to deer antlers and velvet.
So you can see the fuzz on the twig down here in the lower-left image.
So that's where it gets its name with that velvety type appearance to it.
The bark is very smooth and it has these horizontal marks or what we call lenticels which allow for gas exchange so you can see them, they stand out very well and this actually a very large Sumac stem so they don't get much larger than what you see in this image here.
So look for those lenticels and that's something that you won't find on a Tree-of-Heaven stem.
It's important to note the Tree-of-Heaven, or that Staghorn Sumac, I'm sorry, grows in these clonal colonies very similar to how you'll find Tree-of-Heaven growing.
It's also dioecious, which means it also has male and female trees.
So this happens to be a clonal patch of female Staghorn Sumac 'cause you can see the red clusters of fruit on the trees that are persistent through the winter months.
So let's look at Black Walnut here.
So again Black Walnut has that pinnately compound leaf.
You can see the central stem or rachis here.
Oh, want to go back.
And this lead can range anywhere from one to two feet in length, so again a little shorter than what we find most commonly in Tree-of-Heaven.
But again the distinguishing characteristic that sets it apart from Tree-of-Heaven is that it has this toothed or serrated leaf margin and you can see the serrations or teeth along the edge of the leaflets here in the image.
So then of course the fruit, most of you are very familiar with the fruit of Black Walnut.
It is the round nut covered with this husk that turns black soon after it falls from the tree and then you can see the nut here, here's the nut that has been broken open.
So easy way to distinguish it there.
The twigs are not quite as stout as Tree-of-Heaven or Staghorn Sumac.
Interesting to note if you look at the leaf scar, so where the leaf has been removed from the twig.
And we have that right here, you can see the bud sits right above the leaf scar.
But it's a three-lobed leaf scar and it's been said that it resembles the face of a monkey.
So we can say it has a monkey-faced leaf scar.
Then the other distinguishing characteristic about the twig is if we were to cut or slice them open here, like we did in the lower-right image it has what is called a chambered pith and you can see the chambers through the center of the twig here.
So the pith is the center of the twig and you can see the individual chambers in the pith there.
So the bark is much different from the other two species.
It is very dark in color and rough and has this almost interlacing, diamond-shaped pattern to it.
So much different and much easier to distinguish from the other two.
So in summary, we'll start with the leaves here.
So the Tree-of-Heaven leaves are very long, this is a yardstick, so anywhere from one to four feet in length.
They're compound with leaflets, so pinnately compound with a central rachis with leaflets with multiple leaflets and the margins of the leaflets are smooth with one to two teeth found at the base.
Differing from Staghorn Sumac and Black Walnut in which they are both pinnately compound but they have serrations on the edges or teeth on the edges of the margin of the leaf.
Then looking at the twigs, Tree-of-Heaven has that very stout twig, no terminal bud, it has that large V or heart-shaped leaf scar.
Then on Sumac we have the very fuzzy twigs and then Black Walnut we have twigs that are much less stout which contain a terminal bud right at the end of the twig with that monkey-face shaped leaf scar and the chambered pith.
So some things to keep in mind there.
And then lastly looking at the bark, so remember the bark on Tree-of-Heaven shown here has that cantaloupe kind of pattern to it.
It looks like the skin of a cantaloupe.
This is the bark on the Staghorn Sumac, very smooth with those horizontal marks or what are called lenticels.
And then lastly the bark on Walnut is very rough, dark in color and has those interlacing diamond-shaped pattern to it.
So with that I think that's all I have.
And there's my contact information, so if anybody has any questions feel free to reach out to me with any questions.