Education & Outreach

An academic arboretum has two purposes. In its fundamental and most basic role, such an institution serves as a repository for living specimens and the germplasm of plant species. If this goal has been accomplished, a secondary role can be achieved: showcasing these specimens to students and the public, with the intention of increasing knowledge about those trees, shrubs, and herbs. Because they exist in physical space and not as a description in a book or on a computer, the arboretum's cataloged specimens can be seen year-round and from 360 degrees. You can "zoom in" and look as close as you want. Can't find just the right photo of a tree? Go snap one yourself at the arboretum. If you like the organism enough, you may be able to collect some seed and start your own. Short of cutting the specimen down or doing permanent damage, every plant in the arboretum is part of an interactive experience; no screens involved.

In support of this ideal, today we'll show some photos of a recent arboretum tour that Centenary College's Visual Identity and Publications Manager Sherry Heflin was kind enough to photograph. Normally, photos of tours given at the arboretum are not available, since the curator cannot photograph herself while thinking, walking, and speaking. Perhaps the arboretum needs a very expensive autonomous drone with a nice lens for such occasions. Then again, Skynet drones might disrupt the ambience for a group that is supposed to be experiencing nature. 

 All photos below were taken by Sherry Heflin, on October 21, 2024.

The tour began in the oldest part of the arboretum, between Hamilton Hall and the Student Union Building. One of the four black metal arboretum signs marks the northern edge of the arboretum.

For a tour during the fall, fruits are a great topic. The arboretum has many different species of oaks growing in a small area, so it's easy to find acorns and compare them. These small acorns were collected under a water oak (Quercus nigra).

This big acorn was snipped from a Burr oak (Quercus macrocarpa).

Persimmons are ripe this time of year! Here, the arboretum curator holds an example of a perfectly ripe persimmon (Diospyros virginiana).

French mulberry fruits are also edible, but not recommended. These pretty purple fruits weren't as numerous in late October.

The arboretum curator displays the very small seeds of the redbud (Cercis canadensis).

In the arboretum, there are plenty of opportunities to play the game: 'Where's the tree? Where's the vine?'. Here, the arboretum curator points out bright red fruits hanging from a black cherry (Prunus serotina). The bright red fruits actually belong to a vine, Carolina moonseed (Cocculus carolinus).

Ouch! These spiny fruits were produced by the American chestnut hybrid, Dunstan (Castanea dentata).

The arboretum has numerous red buckeyes trees (Aesculus pavia). Here, a Centenary students opens a buckeye fruit, looking for the large seeds.

Buckeye seeds are shiny and look oily. What do you think they smell like?

Competition over resources wasn't the focus of this tour, but a few examples were pointed out. Here we have an interesting example. Two trees are shown here. Their trunks have grown together. The slender trunk, leaning toward the left, belongs to a black oak (Quercus velutina). It was intentionally planted. The big trunk, growing straight up, belongs to a southern red oak (Quercus falcata). The red oak volunteered a few years after the black oak was planted, and the red oak has out-competed the black oak for sunshine, water and nutrients.

Even what looks like a bare stick is worth talking about. At the beginning of the tour, the arboretum curator explains that these is the arboretum's original patch of Hercules-club (Aralia spinosa), planted in the old part of the arboretum, circa 1990. Only three spindly plants remain.

Later in the tour, the arboretum curator points out a thriving grouping of Hercules-club. Here, the curator stands among the Hercules-clubs, holding two trunks. These plants are younger, and yet they are significantly larger. Viewing these plants in person and walking through the landscape, we can easily start to formulate hypotheses.

There is always something to talk about in the arboretum. The landscape is always changing!

Tree of the Week Double Feature: Southern Red Oak (Quercus falcata) and Black Oak (Quercus velutina)

Last week we studied a green ash (Fraxinus pennsylvanica) that has grown and developed in a minimally competitive environment. The reduced competition has resulted in a very nice looking specimen, with a straight, strong trunk and uniformly oval crown. Since the tree stands alone, we are able to appreciate its overall form. You can find that post here.

This week, we have an interesting study of two oaks that have grown in direct competition with one another. The black oak (Quercus velutina) was planted first. In November 1995, this individual was collected as a seedling from the Caroline Dormon Nature Preserve (Bienville Parish). The following January it was planted in the ground of the arboretum, in its present location. Sometime later, a southern red oak (Quercus falcata) germinated in the same spot. One of the two is clearly the better competitor.

Pictured above, we have two different red oak species growing in the same spot. The skinny, leaning trunk belongs to the black oak, which is the older of the two. This tree was planted first with careful consideration. The southern red oak trunk is straight and significantly thicker. The precise age of the southern red oak is unknown, but we know that it is younger than the black oak and it has been in the catalogue since 2004.

Since the two trees have grown together, it's difficult to say much about the overall form of either specimen. For the most part, it appears that the southern red oak has suffered very little from cohabitation: the trunk is straight and the crown is nicely rounded at the top. However, if the black oak were completely removed, we might find that the southern red oak has a lopsided development. For the time being, this is a great spot to compare two different kinds of red oak leaves!

The upper surface of the southern red oak leaf is dark-green and smooth. This species is known for variability of leaf-shape, but all leaves are lobed with bristle-tips. This leaf measures more than 8 inches in length; the petiole measures a little less than 2 inches.

Underneath, southern red oak leaves are a dull brownish-green.

Southern red oak leaves are also fuzzy underneath. They are soft to the touch, rather than waxy like the upper surface.

This is a black oak leaf. It has a dark-green, smooth upper surface, and its shallow lobes are bristle-tipped. Its shape is clearly different from the deeply-lobed southern red oak leaf pictured above. However, keep in mind that, like the southern red oak, black oak leaves vary in shape, too. You can see some of this variety in a post about a different black oak, found here.

Underneath, black oak leaves are lighter in color and very soft to the touch.

The leaves on this black oak feel like velvet underneath, significantly softer than the leaves of the southern red oak.