Black Oak (Quercus velutina) Removal

It's time to retire another specimen from the arboretum, again due to disease and being crowded out by the more successful. A 30-year-old black oak (Quercus velutina) was cut down this past weekend, making more room for its partner tree, a southern red oak (Quercus falcata). On the blog, we saw them first in a post from 2012, as photographed by Bonnie Bernard. Then in 2019, showing both trees healthy.

 

In our last photos before removal, we see the much thinner, leaning black oak trunk and the large, straight southern red oak trunk. Each tree has a sign near the base of the trunk, hopefully helping visitors understand that they are in fact looking at two separate trees―not a tree with two trunks. These two have served as a marvelous example of what competition can look like among trees.

The black oak was intentionally planted with care in 1996. Some time later, the southern red oak volunteered in the same spot and was allowed to grow. Over the years, the red oak has squeezed (strangled?) the black oak out of this location. Earlier this year the black oak finally gave up the fight―it dropped its foliage and the trunk quickly showed signs of deterioration.

On the trunk, just before its removal, we see obvious signs of decay, including bugs scurrying across the pitted, fungal bark. It could remain standing for years before falling in an ice storm or windy weather event. The major reason for removal is unsightliness, followed closely by health risks to the partner-tree. The southern red oak has grown into a very handsome tree.

With the black oak trunk on the ground, we see one long straight trunk with very few branches.

A small brush pile was made from the sparse branches. We broke up the trunk and removed it. Despite some rotting, especially around the bark, most of the trunk wood was solid and hard.

The fall landscape is altered with the removal of the black oak. Note: it's mid-December, and some of our maples are still changing colors; the chalk maples (Acer leucoderme) on the slope are turning yellow-orange and a red maple (Acer rubrum) in the background is a bright red-orange, even on such a cloudy day.

Ideally we want to remove this stump. It's like a dead tooth which provides a disease reservoir for the gums in which it sits. But this stump cannot be easily removed from the healthy trunk of the neighbor which has eclipsed and ultimately killed it.

We will leave the sign in place for a little while, to remind us of the spirited competition and also to remind us to check on the decaying process. Will the southern red oak trunk grow to completely encapsulate the decaying trunk, leaving no sign of the black oak's existence?

Pignut Hickory (Carya glabra)

Due to the extraordinary concentration of species diversity in the arboretum's relatively small space, we have a variety of fall foliage. Some of the trees have already changed color and dropped leaves, while others, most notably the maples and viburnums, are still in the process of showing us their fall colors. The evergreen palms and palmettoes will, of course, be best enjoyed next season, when the wintry landscape is bare and dreary.

But for now, the last two weeks of autumn, we must mention a tree that has gone too long without recognition. There is a handsome tree that produces a brilliant yellow display of leaves every autumn, but then for the rest of the year fades into the background; it requires zero maintenance and does not produce showy flowers or tasty fruits. It has no record in the arboretum catalogue, which means that this individual was not planted by either the current curator or the founder. Perhaps it is a volunteer. It may also have been intentionally planted prior to the founding of the arboretum. Examining its late-autumn guise, we can conclude that this tree is a pignut hickory (Carya glabra), and the below photos highlight its features. 

 

We first note a straight growth pattern. The trunk does not lean. The specimen is growing in rare full sun, next to a derelict lightpole. Classified as shade tolerant, this species would still prefer to get full sun. Its branches are horizontal or ascending, not drooping. We needed a ladder to collect leaves for identification.

Bark on the lower trunk is grey and textured. 

Detail; do you see a weaving or diamond pattern?

Long petioles alternate along the twig.

We see compound leaves, with 7 leaflets, measuring nearly a foot in length. Leaves are turning yellow. This species is recognized for its gorgeous fall foliage.

Leaflets vary in size, with the smallest leaflets at the base.

The terminal leaflet on this leaf measures nearly 5½ inches.

Leaflets have serrated margins. 

Underneath, we do not see the pretty yellow autumnal coloration. Leaflets and stem are pale and a little fuzzy.

Preliminary analysis points to Carya glabra, the pignut hickory. Let's officially start our list of 2026 goals: examine and make a digital record of spring leaves and flowers of this specimen, to strengthen our claim that this individual is a pignut hickory. Finding nuts belonging to this tree would help date it, as it takes more than 25 years of growth to reach maturity. Testing these nuts for edibility would also help, as they are particularly fatty and tasty, even among hickories. Although in the past this individual has produdced little to no fruit, 2026 is a new year with new surprises!

For more information about this species, please consult the following resources:

University of Florida 

Virginia Tech Dendrology 

Louisiana Plant Identification and Interactive Virtual Tours (LSUAgCenter) 

Bayberry (Myrica heterophylla) and Southern Wax Myrtle (Myrica cerifera)

The genus Myrica has a worldwide distribution that covers Eurasia and the Americas. Its ripened berries develop a protective coating of real wax that, in sufficient quantities, can be extracted and used to make candles and other items. Because true wax has historically been a prized commodity, it was previously worthwhile to collect and boil gallons of Myrica berries to skim off their modest wax coat. Now that petrochemicals have replaced the functions of innumerable plant and animal products, the cultural and economic value of this genus has been mostly forgotten. 

In the arboretum, we have two species of Myrica on display: bayberry (Myrica heterophylla) and southern wax myrtle (Myrica cerifera). 

This is our small patch of bayberry (M. heterophylla). It was purchased from Woodlanders Nursery (Aiken, South Carolina), and planted in February 1998. Currently, there aren't any fruits available for inspection. Our bayberry persists, but does not thrive.

On the other hand, southern wax myrtle (M. cerifera) grows happily in the arboretum. In 1985, eight pots of southern wax myrtle were purchased from Clyde Gorum's Nursery (Shreveport), and planted in the newly founded arboretum. Over the past three decades, these plants have launched numerous invasions of the wetland area, attempting total colonization. Today, three of the original plantings remain, the rest having been steadily cut back to make space for other species. The suitabillity of this species to our local environment thus appears to be significantly greater than its M. heterophylla cousin.

The genus name draws on a Greek word, Myrike, with a complicated history. It's associated with the Greek Tamarisk shrub Tamarix smyrnensis. That plant is fragrant and waxy, and is known in Greece as Almyrike. The southern wax myrtle's species name, cerifera, means "waxy." So you might think of this plant as "double-waxy" or even "Waxy waxy."

In this photo, we see one of the original 1985 plantings. This wax myrtle shrub is located on the north side of the arboretum, at the top of the arboretum drainage, where run-off water is funneled from up the hill at the bandshell, dormitories and cafeteria. This shrub has changed shape over the years, and intermittently suffered some damage. Several of our native vines must be periodically snipped from its branches, and the wax myrtle's branches must be pruned back from the railing, as it stretches toward the open sidewalk, vying for more sunlight. Overall, the shrub is well-suited to this spot and has required very little maintenance. 

 

Having this shrub next to the elevated sidewalk allows for easy inspection of the twigs. And look, we see fruits! Rustling the branches also provides a pleasing olfactory experience. Think "bay."

Sometime around 2010, a southern wax myrtle volunteered in the western drainage channel next to a wooden footbridge, which has recently been rebuilt. 

The footbridge was rebuilt just last month, in October. It looks great!

Two arboretum guests hang from the southern wax myrtle shrub. 

Getting up close and personal with the shrub allows us the opportunity to spy the tiny fruits, which will otherwise go unnoticed. In silhouette we see the shapes of the leaves (lanceolate) and the berries which sit along branchlets.

These berries are pale, grey-white, and wrinkled. That's normal.

Each of these berries has a tiny wax coating, like an apple from modern grocery stores, except it's natural wax, not a petrochemical. If you find a gigantic stand of this bush at the correct time of year, you might be able to collect enough berries to make some candles.

External Links

University of Florida IFAS blogpost on Wax Myrtle

National Park Service page on Wax Myrtle

Mississippi Wildlife & Fisheries Department data sheet on Wax Myrtle

Extremely helpful page on the practical extraction and use of northern Myrica species' wax 

Our southern wax myrtle (Myrica cerifera) has something of a confused taxonomic history, as it is related to M. caroliniensis (you can read about that in a paper by Robert Wilbur). 

Gulf Fritillary (Agraulis vanillae)

Now that it's the beginning of November, you can find quite a few Gulf fritillary caterpillars on the Maypop (Passiflora incarnata). Coincidentally or not, a couple of years ago in 2023, we photographed these critters on November 5th! How's that for consistency? This year, chilly, autumnal weather seems to be on the verge of freezing the Maypop vine, so hopefully the little caterpillars enjoy the green foliage while they can. 

You can find the Gulf fritillary caterpillars on the prosperous Maypop vine, growing around the trunk of the deceased red cedar, near the Fitness Center. If you want to study the caterpillars, you will need to turn over some leaves―this one sits on top just for the photoshoot.

The other caterpillars were hidden under the leaves.

 

A couple of caterpillars were briefly relocated for a closer examination.

Examining the whole vine reveals the different sizes of caterpillars. As they grow, they molt, shedding their skin and becoming larger. These developmental periods between moltings are called instars (that's Latin for image, likeness, or kind).

 

The large caterpillar is more than an inch in length, while the tiny caterpillar is more than ¼ of an inch. That little fella is likely a newborn!

How long does it take the Gulf fritillary caterpillars to mature? The answer is about a month, with two or three weeks growing in the caterpillar stage and another week or two developing in the chrysalis.

Helpful Links

LSU AG Center 12-2022 Publication with info on Gulf Fritillaries 

Short Article from Loyola University in New Orleans on the Gulf Fritillary 

Maypop (Passiflora incarnata)

 

A delightful seasonal treasure thrives at the base of an eastern red cedar trunk. See our previous post on this plant here.

Purple flowers bloom on this bush-shaped vine. The flowers seem to be best during the morning hours.

These flowers, some wilting and some blooming, are awesome to behold. Note the sneaky anole, pictured center. That's a reptilian "photobomb."

What amazing colors and shapes are present here, part of a totally wild and unselected plant. And, looking closer, you can see a developing fruit.

And the 'great reward,' a green fruit shaped somewhat like a hen's egg, is hidden among the leaves.

The flesh of these fruits tastes tropical, sweet, and very light.

Visit the maypop before it gets gobbled up by the Gulf Fritillaries! We haven't seen any fritillaries in the arboretum yet, but they were spotted elsewhere in the Parish, presumably laying their eggs. We expect the spiky black-and-orange catepillars to eat these leaves.

Laurel Cherry (Prunus caroliniana)

 

Prunus is a famous, useful, and diverse genus. When you're "kind of a big deal," you typically have more problems come your way.

Here we see sap leaking from regularly-spaced wounds on the trunk of this laurel cherry (Prunus caroliniana).

This is likely the early stages of a condition arborists call "gummosis." The French botanist Auguste Trécul (1818-1896) was first to note, circa 1860, that a condition resulting in a superabundance of sap around a pathological zone could result from a variety of maladies. That name refers to the liquefaction of a tree's inner wood material and its leaking from wounds in the tree. This gummosis, or Gummibildung and even Gummifluss, as the Germans call it, can help protect a tree by isolating infected wood between hardened, protective plates. As it is really more of a physiological response than a disease itself, there is no singular cause of gummosis; it can result from insect damage, climatological stress, or infection by bacteria and fungi. 

Here we can see an old wound and the gummosis above it.

Back in June, this tree was placed on the docket for removal, primarily because of its significant lean. You can read that post here. The gummosis is not the reason for removal, but it did speed up the process. Enquiring minds want to know―what does the inner bark look like given the external gumminess? Is there a bug infestation or is it rotting? So the Faustian spirit urges, "Cut it down! Let's find out!"

 We are fortunate to have a volunteer ready to take its place. We'll stake that one and try to avoid the leaning tower of laurel.

In order to avoid destroying the smaller laurel cherry at the base, we first took out all the branches. Cutting most of the way through allowed us to extract the plant material slowly.

Here the tree has been separated into trunk and branches for easier disposal.

Here we can see the damage at the base of the trunk, which probably gave rise to the gummosis. Our working theory is that this damage was isolated and more-or-less healed by the tree. Later attacks by bugs or sapsuckers, in a vertical line from this damage, resulted in the tree leaking sap due to its proximity to the old wound.

The trunk ought to be round—and a crescent-shaped portion is clearly missing. What we don't see here is a lot of rotten material, a bug infestation, fungal infection, or other bad signs. The tree was, at least right now, apparently healthy despite the manifestation of gummosis. Nevertheless, we stand by the decision we made to cut it down, in large part due to the uncorrectable lean. In an unexpected turn, this newly cut lumber produced an aroma which corresponded precisely to a cherry soda.

All cleaned up and immediately replaced by the volunteer, who will reap great rewards in sunlight, nutrients, and water.

A Bacterial Gummosis of Cherries (1911) by F. L. Griffin

Gummosis of Prunus & Citrus (1911) by Ormond Butler