University of Tennessee Forest Resources Research Center

Two large, impressive trees in the Arboretum’s Conifer Collection are the Japanese Cedars on the hill above the Program Shelter. These are not true cedars, but belong to the Cupressaceae family, which also includes junipers, bald cypress, arborvitae, and redwoods. A dwarf form of this tree can be found in the Dwarf Conifer Collection. This ancient tree is the National tree of Japan and is also called "Temple Tree" for its use in building the centuries-old Shinto temples. It has a pyramidal, conical shape with somewhat pendulous branches. It is evergreen, grows 50-60 ft high (though old trees as high as 230 ft have been reported).

Japanese Cedar has blue-green, needle-like leaves and a red-brown bark that peels off in vertical strips. The seed cones are globular. It is a forest tree native to Japan (16% of Japanese managed forests are of Japanese Cedar). It has a wide variety of uses in construction and the manufacture of furniture, utensils, and paper. It is cultivated as an ornamental, landscape tree, and is frequently used for Bonsai.

Sweetgum (Liquidambar styraciflua)

Sweetgum is a deciduous tree that holds onto its leaves late into the fall. In December one can still find occasional trees with a few yellow to purple leaves along with conspicuous stalked, spiny fruits hanging from the branches. At the Arboretum, Sweetgum is most commonly found along the Old Kerr Hollow Road in a relatively moist habitat.

Sweetgum is found in much of the Eastern U.S. south of New England. The fruits consist of seed pods united into dense spiny balls. The bark is deeply furrowed into narrow ridges, and the twigs often develop corky ridges along their length. The lobed leaves, which resemble maple, have a pungent odor when crushed. The gum from which Sweetgum derives its common name has been used since before the 16th century for incense, perfumery and medicinal purposes. Sweetgum lumber has a variety of uses such as furniture, crates, cabinets, and barrels, and its distinctive heartwood is often referred to as "red gum" lumber. It is also an important shade tree.

Japanese Umbrella Pine (Sciadoitys verticella)

Mid to Late December

One of the more interesting trees in the Arboretum’s Dwarf Conifer Collection is the Japanese Umbrella Pine. The common name of this tree comes from the long green, needle-like "leaves" that occur in whorls resembling the spokes of an umbrella. These photosynthetic "leaves" have been interpreted as actually being stem tissue rather than leaf tissue and are referred to as cladodes. They persist for 3 years. The true leaves are small brown, scale-like structures that are found along the shoot between the whorls of green cladodes and are also tightly clustered around the bases of the cladodes.

The slow-growing Japanese Umbrella Pine can reach a height of 20-30 feet. Its reddish-brown bark peels off in strips. In its native Japan, this species grows in cool, moist, mountainous environments. The wood is used in Japan for building boats. Several cultivars have been developed as unusual landscape trees. As the sole member of the plant family Sciadopityaceae, the Japanese Umbrella Pine is known from the fossil record as far back as 230 million years.

Winter Fruits

Late December - Early January

As one walks the Arboretum trails at this time of year, the fruits of a variety of woody plants and vines can be seen. Our native Dogwood, American Holly and Greenbriar are found along with several non-native, invasive plants, such as Oriental Bittersweet, Chinese privet, and Amur Honeysuckle. Some of these fruits, such as those of the Dogwood provide food for a variety of birds (e.g., robins, cedar waxwings) and small mammals. Six of the more common winter fruits found at the Arboretum are described below.

Left: Flowering Dogwood (Cornus florida)
Right: Oriental Bittersweet (Celastrus orbiculatus)
American Holly Fruit

Left: American Holly (Ilex opaca)
Right: Chinese Privet (Ligustrum sinense)
Amur Honeysuckle Fruit

Left: Amur Honeysuckle (Lonicera maackii)
Right: Greenbriar species (Smilax sp.)

Japanese Cedar (Cryptomeria japonica)

Sweetgum (Liquidambar styraciflua)

Japanese Umbrella Pine (Sciadoitys verticella)

Winter Fruits