Tree of the Week: Black Oak (Quercus velutina)

Healthy trees are always growing, and in many cases, upward growth results in a loss of lower branches. It's no coincidence that the majority of mature trees in the arboretum lack their lower limbs. Healthy branches are often removed to make the landscape more accessible for foot traffic or, for safety concerns, to increase visibility. Some species take care of this for us; the trees naturally shed their lower limbs. Yet these dead branches don't immediately fall off a tree and may remain attached for years. While we normally allow these things to resolve themselves naturally and clean up the mess, sometimes we need to be proactive.

This past week, we decided to remove the unsightly dead branches from a black oak (Quercus velutina), located near the fitness center. This individual had accumulated a large number of dead branches, and since it's growing on the periphery of the arboretum, in a high-traffic area, we decided to improve its appearance. Here we show the results:

 

Our tree of the week is a black oak (Quercus velutina) that needed some cosmetic work done. This tree was planted near the Fitness Center less than 25 years ago but details of its planting history are unavailable.

 

A ladder was needed to do the tree trimming. These surface roots made it very difficult to position the ladder on solid ground. Be careful when doing this kind of work!

The surface roots are thick and bulbous, showing obvious signs of damage from lawn equipment.

Surface roots of Quercus velutina, photographed October 7, 2023

Surface roots of Quercus velutina, photographed October 7, 2023

Protruding from the ground makes these roots a sure target of lawnmowers and trimmers.

These dead branches started about eight feet above ground level and continued to around fifteen feet up. That required some climbing!

The tree looks a bit sparse, but much better overall.

With the dead branches removed, we can appreciate the black oak's straight trunk and dark bark.

These dead branches were all removed from one tree.

We will be watching this black oak over the next couple of months; we are expecting pretty fall foliage from it. Our appreciation of the color change won't be marred by those ugly dead branches.

And we have another reason to check-in with this tree in the coming months: acorns were spotted. Not many, and, of course, they are out of reach. Can you see one?

Quercus velutina acorn, photographed October 7, 2023

Tree of the Week: Shumard Oak (Quercus shumardii)

Our tree of the week is a recently germinated oak seedling. In the above photograph, we can see the acorn, visible at the soil surface.

So, which species of oak is it? Looking at the pointy leaves, it must be in the red oak group.

 

The acorn germinated this winter, under a Shumard oak (Quercus shumardii), which was featured on the blog this past September for our Acorn Watch 2022 (found here). The hard outer shell of the acorn resembles a Shumard oak acorn. Furthermore, there are two additional Shumards nearby, and the other oak species in the immediate vicinity are either white oaks or their acorns do not resemble the acorn shell found here. So, leaving aside, at least for now, the difficulty of oak hybridization, it seems safe to say that this is a new Shumard oak in the arboretum collection.

Fortunately, this seedling was easy to dig up and it appears that the new taproot is in good condition. The above ground growth measures nearly the same length as the taproot.

The taproot measures approximately 7 inches in length.

During the digging process, the soil fell away from the root. The new tree had not yet full immersed itself in its surroundings. Hopefully it won't be too traumatized by the move. It has now been added to the grassy slope on the north side of Cline Hall, and it has a full-sun location, with plenty of room to stretch up and out.

2022 Acorn Watch

 

We have more post oak (Quercus stellata) acorns to add to our on-going germination project. These acorns were collected this past week in the Piney Woods region of East Texas, south of Jacksonville. They've since been potted, so now we wait to see who sprouts and who doesn't.

These water oak (Quercus nigra) acorns were collected at the same time from the same property. They have been potted as well. The arboretum is currently home to seven mature, on-site native water oaks, but we do not currently have any young water oaks in the collection.

2022 Acorn Watch: Swamp White Oak (Quercus michauxii)

 

This past week, we found both ripe and ripening acorns in the leaf litter under our large swamp white oak (Quercus michauxii). There weren't many fruits―only these five. In hindsight, it would have been worthwhile to count the empty caps.

The ripening acorns are very pretty―the caps are pink!

The ripe fruits are shades of brown.

2022 Acorn Watch: White Oak (Quercus alba)

In the middle of November, our younger white oaks (Quercus alba) have ripening fruits. In this photo, the leaves are still mostly green, while the acorns are a light pink.

 

On the same tree, on the same day, we see a little autumnal red on these leaves.

 

2022 Acorn Watch: Post Oak (Quercus stellata)

Our time has come round at last―post oaks are dropping their acorns! 

A year ago, our old, on-site native post oaks showed no signs of acorn production. Campus trees were inspected, as well as two large stands in Caddo parish. This was troublesome because the continued diminution of the campus post oak population necessitates a germination project. Back in September, our sights were set on the two old post oaks near the Sam Peters Building, simply because acorn clusters were identified. Pictured below are the first participants for our germination project. 

Two mature, on-site native post oaks are pictured center, in the above cluster of trees. They stand at the top of a hill near the Sam Peters Building. A mature, on-site native southern red oak, also pictured, has been growing alongside these post oaks for a very, very long time.

A total of 16 post oak acorns were collected, but only 10 were selected to be planted. The chosen 10 are shown in the above photo. More acorns will hopefully drop; these are just some of the first ones to hit the ground. Keep in mind that the Centenary campus squirrel population is vigorous and mostly uncontrolled, so the arboretum curator has fierce competition for these gems.

One acorn already started to sprout! Hopefully we found it at the right time. These 10 acorns are in the dirt and watered in. Let's see what happens!

2022 Acorn Watch: Overcup Oak (Quercus lyrata)

Overcup oak acorns are ripening. On the tree, we see both the acorn and its cap turning from green to brown, and in the leaf litter we see fully ripe acorns. All of the photos below are from October 30, 2022.

Two acorns have turned brown, indicating ripeness, but remain attached to the tree.

This acorn is in the process of turning brown.

The cap on this acorn is unexpectedly revealing, allowing us to see the acorn itself.

In this photo, we see a ripening nut with a cap that hasn't lost its greenness.

All of these acorns were found in the leaf litter. These are big fruits, easy to spot, if you happen to be looking for them.

Overcup oak acorns, photographed October 30, 2022

2022 Acorn Watch: Blackjack Oak (Quercus marilandica)

 

This week in the arboretum, have a look at our diminutive blackjack oak (Quercus marilandica). Its leaves are changing colors, and you can examine its ripening acorns. The acorns may very well drop in the next few days.

You can find this blackjack oak on the grassy slope near Cline Hall. It grows by itself, in full sun, and it is clearly labeled with a sign.

 

Although it is more than 25 years old, this tree remains relatively small. Approximately two decades ago, vandals broke the trunk off down to the ground. The tree defiantly re-sprouted and was then replanted in a different location, and despite that difficult life history it appears to be in good health.

 

However, looking at the above photograph, on the right side of the trunk, we see that the base is malformed. Even though this tree resprouted, it sustained a permanent injury from the act of vandalism. It may also be the case that this tree is stunted. Today, it stands at a height of 7 feet, 8 inches.

 

It's short, but still producing acorns! And since the tree is small, we can easily observe the little gems. This week they are turning brown.

Ripening blackjack oak acorn, pictured October 30, 2022

 

You can see an old fall foliage picture of this individual here.

For additional information about this individual and for spring time photos, click here.

 

2022 Acorn Watch: Swamp White Oak (Quercus michauxii)

 

Today in the arboretum, a double-handful of acorns was found under one of the two elder swamp white oaks (Quercus michauxii). Thus far, the swamp white oaks have not been included in 2022 Acorn Watch, primarily because all of their lower limbs are far out of reach. Luckily, the larger of the two trees grows near a sidewalk; the newly-fallen acorns were noticed very quickly after they accumulated on the concrete.

 

 

 

 

 

 

The swamp white oak under discussion is approximately 30 years old. It is pictured center, growing at the junction of a sidewalk and a gravel path, and near the arboretum drainage channel, which, as shown in the above photo, is thick with Louisiana palmettos. Since the drainage channel is a main watercourse for the arboretum and since palmettos are a water-loving species, we can say that the tree is satisfying the "swamp" conditions of its name.

The lower section of the trunk is pale and bare, with no low-hanging branches. Up past the bifurcation, out of reach, is where all the acorn clusters have been hiding.

Peeling, flaking bark is characteristic of this species and the white oaks generally.

Some acorns are turning brown (which may indicate ripeness) while others are still green. In an older blog post, found here, we see ripe swamp white oak acorns appearing in the leaf litter at the beginning of December. Perhaps these acorns dropped prematurely due to the particularly windy weather we had over the weekend.

These specimens are large, regular, beautiful, well-proportioned acorns. Truly an ideal for what any acorn should aspire to be.

2022 Acorn Watch: Overcup Oak (Quercus lyrata)

 

This week in the arboretum, check out the developing acorns on the overcup oaks (Quercus lyrata). There are four overcups in the collection, spread out across the arboretum, and each one has at least a few acorns. The specimen pictured below has more than its fair share.

We discussed this individual back in August. At the time, the tree was covered with a profundity of immature acorn clusters, and the individual acorns were mostly concealed by the large caps. You can find those pictures here. Today, as we see from the following images, the acorn itself is visible and the caps vary in size.

This particular tree makes studying acorns a pleasure. Can you see how the lower branches nearly touch the ground as it slopes upward toward Rotary Hall? And there are acorns on these lower branches! No ladder necessary.

Some acorns are solitary.

And there are several clusters as well. You can easily maneuver the branches to study the acorns and appreciate the different textures: the cap is very bumpy, while the acorn itself is smooth.

Immature overcup oak acorns, photographed October 9, 2022

With so many immature acorns to examine, we can see variations.

We snipped two acorns to take measurements and to show the variation in cap shape. These are large fruits, and we see in the above photo that they are already more than an inch in length. The caps cover different proportions of the acorn. The cap on the left nearly engulfs the whole fruit.