University of Tennessee Forest Resources Research Center

Bald Cypress is typically a Coastal Plains tree that is found in swamps and other wet areas. However, it is often planted in drier habitats where it thrives. Younger trees are pyramidal in shape and may grow up to 150 ft in height. It is a deciduous gymnosperm — the green needle-like leaves turn brown before being shed each autumn. The round green cones turn brown at maturity. At the Arboretum a number of Bald Cypress trees are planted in the Marsh Area, along Scarborough Creek, and in an area above the Program Shelter next to the Oak Collection.

A unique feature associated with Bald Cypress is the development of cypress knees, which are outgrowths from the root system that grow upward around the trees on wet sites. Although the function of these knees is unknown, it has been postulated that they facilitate gas exchange in the low oxygen environment of wetland habitats and/or provide support for the shallow-rooted trees. The decay-resistant wood has many uses in construction, such as docks, bridges, and buildings.

Resurrection Fern (Pleopeltis polypodioides)

Among the interesting ferns found at the Arboretum is the Resurrection Fern which can be observed on several Eastern Red Cedar trunks along the Cemetery Ridge Trail. It also occurs on rocky ledges off the trails. The fern is an epiphyte (or air plant) — a plant that uses another plant as a substrate but does not depend on that plant for food, nutrients, and water as does a parasitic plant.

During dry periods, the fern’s fronds appear shriveled. The common name is based on the fern’s ability to expand quickly (i.e., resurrect) in response to a rainy period, such as the rain we had at the end of August. The fern obtains its water and nutrients directly from rainwater and the wet bark or other substrate on which it grows. Resurrection Fern is widely distributed in Tennessee and the Southeastern U.S.

Honey Locust (Gleditsia triacanthos)

As you walk along Marsh Road, you will find two large trees with large thorns on their trunks. These Honey Locusts (or Sweet Locusts) have abundant yellowish, bean-like pods hanging down from the branches. The compound leaves are bi- or tri-pinnate (leaves divided two or three times). The native range of Honey Locust extends from central Pennsylvania south along the Appalachians to Alabama and west to Texas and the Central U.S.

Honey Locust belongs to the plant family Fabaceae (the bean or pea family). The large pods, which are yellowish now, turn brown as fall progresses and may persist into winter. The pods are sweet and eaten by cattle, hogs, and wildlife (thus the name "honey" or "sweet"), and the rattling of the seeds in the pods is said to resemble the singing of locusts (thus the second part of the common name).

The conspicuous thorns on the trunk and limbs are modified branches—they occasionally bear leaves. These have likely evolved over geologic time as protection against large herbivores. In the past, the very hard thorns have been used as nails, for carding wool, and as pins for closing sacks. The durable wood has been used for railroad ties, fence posts, and pallets. A number of thornless varieties have been developed for shade and ornamental use.

Eastern Red Cedar (Juniperus virginiana)

A former Eastern Red 'Cedar Barrens' being replaced by deciduous forest.

Eastern Red Cedar (also known as Old Field Juniper) is a small to medium sized coniferous tree with scale-like or awl-like leaves and bluish, berry-like fruits. It is widespread throughout the eastern U.S. and adjacent Canada. It invades open areas that have been disturbed by fire or cleared for agriculture. Areas dominated by Eastern Red Cedar are referred to as “Cedar Barrens” and are present in the Oak Ridge area. Eastern Red Cedar trees may persist in older forests for many years, and their presence may provide evidence of past land use for agriculture or other human or natural disturbance.

The female cones of Eastern Red Cedar develop into bluish “berries” with a waxy coating. These fruits are an important winter food source for birds, which disperse the seeds widely.

The aromatic wood repels insects and is used for lining cedar chests and as fence posts. The tree is also planted for windbreaks and used for making pencils and for Christmas Trees in the South. It is an alternate host for cedar-apple rust and should not be planted near fruit trees .

River Birch (Betula nigra)

Early to Mid September

A beautiful example of a River Birch cultivar (‘Heritage’) can be seen next to Scarborough Creek just below the Arboretum entrance. River birch is found throughout the Southeastern U.S. and ranges from southern New York and Pennsylvania, west to Indiana, and south to Texas and Florida. It is found on moist soils along stream banks, floodplains, and swampy bottomlands and can play an important role in stream bank erosion. It grows to heights of 50-75 ft and has alternate, doubly serrate (both fine and coarse teeth) leaf margins that are triangular in shape.

Its attractive, scaly, beige-colored bark is a conspicuous feature that makes River Birch desirable as a landscape tree. The knotty wood has limited value for lumber but is used for pulp and as firewood. Another native birch found at the Arboretum is Sweet Birch (Betula lenta), which is present at the junction of the North Loop Rd and Backwoods Trail, as well as at other places along our trails.

Allegheny Chinkapin (Castanea pumila)

Allegheny Chickapin is a shrub or small tree found in the foothills of East Tennessee and on the Cumberland Plateau. Its range extends from Pennsylvania, Ohio, and New Jersey, south to Florida, and west to Texas and Oklahoma. It is closely related to American Chestnut (Castanea dentata) and Chinese Chestnut (Castanea mollissima). The species has a number of varieties, some populations of which are susceptible to Chestnut Blight, which eliminated American Chestnut as one of the dominant trees of the eastern deciduous forest. Other Chinkapin populations are at least somewhat resistant to this disease. Allegheny Chinkapin may grow as high as 65 ft, but typically it is a shrub only growing to heights of 30 ft or less. Its oblong leaves have fine to coarse, bristle-tipped teeth along their margins and are densely pubescent underneath. The shrub produces showy unisexual male catkins that are as long or longer than the leaves. Shorter bisexual catkins bear female flowers at their base and male flowers along the rest of the axis. The fruits, consisting of bristly husks (burs), contain 1-3 nuts and are considered by some to be tastier than the American Chestnut. They are a prime food for a variety of wildlife.