Volunteers in the Arboretum

As we continue to clean up the volunteer recruitment area and make it more accessible, we also document the species that have taken root in this green space. Since the volunteers are by necessity an unmanaged population, this is an interesting sample of what survives the struggle for existence.

This week we are clearing a path around a looming specimen: our only large, on-site native southern red oak (Quercus falcata). It is the large trunk pictured center. Most of its upper branches are out of the frame.

 

 

Seen from another vantage, the same mature southern red oak (Quercus falcata), and the red bricks of the Student Union Building are seen in the background.

Over the past few years, we haven't had a path around the base of this trunk.

Until today, the tree sign was hidden by the undergrowth. The area is thick with vegetation. Numerous volunteers are present with several different species represented.

Now, things have changed. First, the area was carefully surveyed for possible recruitments to the arboretum catalogue. This process involved weeding by hand―pulling up dewberry and snipping little trees. A few individuals, currrently very short in stature, were identified as candidates (we will let them grow up a little more before making it official). Then, this area was cut with a lawnmower to make a clear path.

Now, you can clearly see the sign.

Most of the volunteers around the southern red oak were removed or cut back to the ground. Only a few were left unharmed, and they are not visible in this photo. 

The photos below showcase the most conspicuous volunteers that were removed. These individuals were quick to colonize a new territory and were winning in the competition for survival. Unfortunately, they didn't germinate in a space deemed suitable by the arboretum curator.

chittamwood (Bumelia lanuginosa) REMOVED.... Although another chittamwood nearby will most likely be added to the arboretum's collection; it is located further away from the red oak's trunk.

oak (Quercus sp.) REMOVED

trident-leaf maple (Acer buergerianum) REMOVED

goldenrod (Solidago sp.) REMOVED

trumpet creeper (Campsis radicans) REMOVED

elm (Ulmus sp.) REMOVED

redbud (Cercis canadensis) REMOVED

nandina (Nandina domestica) REMOVED

non-native holly (Ilex sp.) REMOVED

red mulberry (Morus rubra) REMOVED

Mexican plum (Prunus mexicana) REMOVED

non-native privet REMOVED

Virginia creeper (Parthenocissus quinquefolia) REMOVED

dewberry (Rubus trivalis) REMOVED This species was heavily represented around the base of the red oak trunk; the ground was thick with dewberry. This species is very successful in the ground of the arboretum.

The Arboretum's Unintended Creche

Nice and tidy in the front, but is there a party going on out back? In the center of the photograph, directly behind the sidewalk, we have two non-native gummi berry shrubs (Elaeagnus multiflora). Grass and weeds have been removed from around the bases of the trunks so that the shrubs are distinct from the surrounding landscape. Much of the arboretum is maintained in this fashion.

The primary goal of the arboretum is to showcase trees and shrubs native to the southeastern United States. As exhibited in the above photograph, some non-natives are allowed. While we would prefer to have only native species, this is unobtainable. This problem is especially noticeable with our grasses. The commercial species of grass present in the arboretum tolerate mowing and have a relatively short growth-height: these grasses can be kept alive and healthy while remaining short enough to allow guests to see the trees and shrubs and their binomial placards. If we were to remove all the non-native grass species, we would be unlikely to find replacements that would prevent erosion without obscuring the trees, shrubs and signage. Our native grasses, such as little bluestem (Schizachyrium scoparium), are typically clump-forming and tall—you will not get a lawn with these plants. Historically, the grass in the aboretum was kept more-or-less just as it is across the rest of campus, i.e. short. Over the last few years, however, one area has grown into a mini wilderness area, directly in the middle of campus.

 

This sidewalk marks the western edge of the arboretum. The grass is kept short next to the sidewalk, for a number of reasons. The uncut wilderness area is photographed in the center, with a sycamore (Platanus occidentalis) pictured on the left and a large, on-site native southern red oak (Quercus falcata) on the right. On the far right of the photograph we see a grouping of Mexican plums (Prunus mexicana).

 

How many species are growing here?

 

Near the Student Union Building, you may notice a large uncut plot. This area has not been mowed since spring 2021. Ms. Beavers, an art student, displayed her project in this area, so cutting was neglected to avoid damaging the artwork. After the project was concluded and the artwork was removed, wildflowers were blooming, so the area was given a further reprieve in order to complete its reproductive cycle. Once the wildflowers were gone to seed, volunteer trees had made their presence known by sticking their heads shoots up above the grasses. We then made the decision to leave the area alone for the foreseeable future. 

 

A sycamore trunk is photographed center. The sycamore (Platanus occidentalis) is properly labeled with a sign, but the sign is nearly overgrown. A diverse group of plants thrives beneath this one tree. What sort of volunteers are begging to be put into service?

 

 

New trees must be replanted every season to replace those that die from old age, disease, or damage. In this photograph, we have two new trees staked, and the surrounding grass has been trimmed to draw attention to the new recruits. In the background, we see what the landscape looks like if allowed to grow without being trimmed.

 

As often shown on this blog, trees and shrubs in the arboretum die off every season. Volunteers are an excellent insurance policy, and they have been naturally selected for vigor and suitability. The death of an American holly (Ilex opaca) created the sunlight and open space necessary for this "nursery" to form. Now, by 2024, there are numerous tall and healthy volunteers. Unfortunately they can't stay here forever; the time has to come to choose which to harvest for transplants. Then we will decide what to do with this area: clean it up or allow it to thrive as a semi-wild pocket.