University of Tennessee Forest Resources Research Center

As you walk through the Arboretum’s Marsh Area in late October/early November, you may notice a tall conifer with leaves changing from green to bright yellow. This Japanese Larch is native to central and northern Japan. It is planted in Japan and northern Europe (including the British Isles) where its decay resistant wood is used for construction and fences. It is also the most popular of the larches for use in Bonsai. Japanese Larch can grow to more than 100 feet in height with spreading branches that give it a cone-shaped appearance.

First-year shoots bear single leaves (needles), while older branches bear clusters of needles (up to 60 per cluster) on short shoots. Japanese Larch is one of several deciduous conifers at the Arboretum — others include Dawn Redwood (Metasequoisa glyptostrboides), Bald Cypress (Taxodium disticum), and Pond Cypress (Taxodium ascendens). Typically larches are trees of mountains or high latitudes. Three species of larch are native to North America: Tamarack (Larix laricina) is a component of boreal forests and peatlands in Canada and the northern U.S., extending south into Ohio, Pennsylvania, and West Virginia; Western Larch (L. occidentalis) occurs in the Northwestern U.S. and adjacent Canada; and Subalpine Larch (L. lyalli) grows at or near timberline in the mountains of the Pacific Northwest.

Ginkgo (Ginkgo biloba)

Late October to Early November

Ginkgo (or Maidenhair Tree) puts on its spectacular fall display in early November. For a short period its leaves turn bright yellow, and then almost overnight, they fall to the ground creating a conspicuous leaf shadow under the tree’s spreading branches. A beautiful Ginkgo can be seen across the Arboretum entrance road from the Visitors’ Center, and another is located near the end of Marsh Road as it turns up to the Forest Loop Roads.

Ginkgo is a Gymnosperm - its developing ovules and seeds are not enclosed in an ovary. Its fan-shaped leaves resemble those of Maidenhair Fern (hence its common name) and have dichotomous (forked) venation. Ginkgo is well-represented in the fossil record. For thousands of years it only survived in temple gardens in China, and no wild populations are known to exist. The tree is often referred to as a living fossil. Ginkgo is dioecious (i.e., meaning two houses) with separate male and female trees. The male trees are most commonly planted because the female trees produce fruits with a strong, malodorous odor. Ginkgos are hardy trees that are planted in many parts of the U.S. and elsewhere. Extracts from Ginkgo leaves have been used for medicinal purposes for many years.

Red Maple (Acer rubrum)

Early to Mid November

Red Maple is found on a wide variety of sites throughout the Arboretum’s forests. Its fall foliage presents a brilliant display of color from bright yellow and orange to red. The opposite, palmate leaves are mostly 3-lobed but sometimes have 5 lobes. In the summer, the leaf petioles (leaf stalks) are often red and the undersides of the leaves are pale green to silver. In spring, red maple is one of the earliest trees to bloom (as early as February or March). Its small red flowers produce abundant seeds that are eaten by squirrels, birds, and other wildlife.

Red maple is found throughout the Eastern U.S. and Midwest — from the Maritimes in Canada and New England, to Florida, and west to Texas and Minnesota and states in-between. A number of excellent cultivars are available that are among the most popular landscaping tree species available.

Chinese Quince (Pseudocydonia sinensis)

As you walk from the Program Shelter along the edge of the Arboretum’s Shade Tree Collection in early November, you may notice a tree bearing large globular fruits, many of which have fallen to the ground. As its name indicates, Chinese Quince is a native of Eastern China. Although related to other European and Asian Quinces, it has been placed in a separate genus. It may grow from 10 to more than 40 ft in height and develops a dense, twiggy crown. The alternate, simple, dark green leaves have serrated margins and turn yellow to red in the fall. The attractive fluted bark is flaky and is said to resemble the bark of Sycamore. Chinese Quince has been used to treat such illnesses as asthma, the common cold, and tuberculosis. The hard, dark red wood is used in making a variety of items such as knife handles, wooden bowls, musical instruments, and picture frames.

A member of the Rosaceae plant family, it produces fragrant, pink flowers in the spring — our specimen was in flower at the end of March in 2011. The large (as much as 7 in. long and 4 in. wide), astringent fruits become sweeter after frost and are used for making jams, syrups, and liqueurs.

Chinese Parasol Tree (Firmiana simplex)

One of the interesting trees in the Shade Tree Collection at the Arboretum is a Chinese Parasol Tree. In late October and early November, its large leaves (up to 12 in. wide) are bright yellow gradually turning to brown. This native of China, Japan, and southeast Asia, a member of the Cacao (cocoa) family (Sterculiaceae), is planted as an ornamental tree in the Southeastern US and has become naturalized in a few locations. The Chinese Parasol Tree grows rapidly to heights of 30 to 50 ft and develops vigorous sprouts around its base that need to be cut back periodically. This sprouting often results in multiple trunks. The wood has been used to make furniture and coffins. Medicinal uses have included salves and lotions to reduce swelling and treat such conditions as hemorrhoids, carbuncles, and sores.

In July, numerous branched inflorescences bear fragrant yellow/orange/green flowers that attract such pollinators as butterflies and bees.

The relatively smooth, light-colored bark has a greenish tint and has been used for fiber to make cordage and cloth. The female flowers develop into brown pods which split into four sections and are said to resemble parasols.

Chinese Mountain Ash
(Sorbus koehneana)

A large tree near the end of Marsh Road in the Central China Collection is an interesting representative of the Mountain Ash genus (Sorbus). Chinese Mountain Ash is a native of temperate regions in China. It is usually described as a large shrub or small tree that has pinnately compound leaves. Our specimen appears to be unusually large for the species. In the spring, Chinese Mountain Ash bears clusters of white flowers. As the season progresses, the green berries develop into white fruits. Our native American Mountain Ash (Sorbus americana) is found in the mountains of East Tennessee. It is smaller than Chinese Mountain Ash and bears red berries. In Europe, members of this genus are referred to as Rowans.

Harry Lauder's Walking Stick
(Corylus avenella) 'Contorta'

A recent addition to the Arboretum’s plant collections near Scarborough Creek below the Visitors Center is a shrub with highly contorted branches. Harry Lauder’s Walking Stick (also known as Contorted Filbert or Corkscrew Hazel) is a cultivar of European Hazel and belongs to the same genus as American Hazelnut and Beaked Hazel, both of which can be found in Tennessee. A larger specimen of Harry Lauder’s Walking Stick has been growing for many years with the Arboretum’s Dwarf and Unusual Conifer Collection.

This cultivar is named after a famous Scottish comedian and singer who used a crooked cane as a prop during his performances in the late 1800’s and early 1900’s. He traveled widely and was knighted in 1919 by King George V for his many contributions to the war effort during World War I. He continued supporting the troops during World War II. The curling, twisted branches are most conspicuous during the winter after leaf fall.

Dawn Redwood (Metasequoia glyptostroboides)

Mid-Late November

Dawn Redwood is a deciduous conifer with flat, needle-like leaves that turn a copper-colored brown in November before falling to the ground. A tall specimen of this tree, planted in 1965, can be found at the upper end of the Arboretum’s Marsh Area. Dawn Redwood is related to the Southeastern Bald Cypress (Taxodium distichum) and California’s Redwood (Sequoia sempervirens) and Giant Sequoia (Sequoiadendron giganteum). In the early 1940s, a Chinese paleobotantist recognized that fossils initially thought to belong to the genus Sequoia should be reassigned to a new genus, Metasequoia. In 1945, living individuals of Metasequoia glyptostroboides were found in the Sichuan Province of China. Extensive field surveys in the late 1940s found this “living fossil” present in limited populations in Sichuan and neighboring Hubei Province.

Propagation of seeds and cuttings at arboreta in the U.S. and elsewhere have resulted in Dawn Redwood becoming available for planting. This conifer is fast growing, and, although the oldest U.S. trees were planted in 1948, some have attained diameters of over a meter. Dawn Redwood can be distinguished from Bald Cypress by several characteristics - the buds develop on the underside of the branches rather than along the tops as do those of other conifers; the base of the trunk is fluted and buttressed; and the branches have rounded depressions below their junction with the trunk.

Sycamore (Plantanus occidentalis)

Mid to Late November

Sycamores are found in many places throughout the Arboretum, but are especially abundant along Old Kerr Hollow Road. As winter approaches and leaf fall occurs, Sycamores stand out in the forest with their upper trunks a skeleton white. The outer bark on lower portions of mature trees breaks into pieces leaving a patchy mosaic of brown, green, and gray overlying the inner white bark. Other key characteristics include large (4 - 8 in. wide), coarsely toothed leaves that are 3 - 5 pointed and a single ball-shaped fruit on the end of a long stalk.

Sycamore is a massive tree, growing 80 to 100 ft high with wide-spreading branch and root systems. It is found throughout the Eastern U.S., often in bottomland forests but occupies a variety of upland habitats as well. The leaves, pollen, and fruits of sycamore are allergenic. The London Planetree, a common street tree in many countries, is a cross between our native Sycamore (P. occidentalis) and the Oriental Planetree (P. orientalis). The London Planetree can be recognized in the fall by having 2 or 3 fruits on each stalk.

American Chestnut (Castanea dentata)

American Chestnut was a dominant tree in the eastern deciduous forest before the early 1920’s. Sources indicate that as many as one in four trees in our forests may have been American Chestnut. It provided durable lumber, tannins, and edible nuts. The arrival of the Chestnut Blight in the early 1900’s, however, resulted in the virtual elimination of this species by the 1940’s. As Richard Evans discusses in his 'Tree'-mendous Facts article “The Lost Chestnuts”, old stumps and root sprouts of American Chestnut were present in Arboretum forests until recently and were the basis for developing and naming the Lost Chestnut trail. These remnants have now mostly disappeared, although root sprouts may still be present in the area.

In a talk at the UTAS annual meeting in November 2011, Bryan Burhans, President and CEO of the American Chestnut Foundation described the Foundation's efforts to develop blight resistant hybrid chestnuts from crosses between American Chestnut and Chinese Chestnut. A principal challenge is to develop hybrids that have the blight resistance of Chinese Chestnut but otherwise possess characteristics of the American Chestnut, including rapid growth, production of large numbers of chestnuts, and the ability to compete successfully in natural forest environments with other native species. Hybrids that are more than 90% American Chestnut are currently being tested at many different locations in the Eastern and Midwestern US, with the understanding that different hybrids that can adapt to different geographic regions and habitats will be needed.

UT researchers have been conducting studies to identify blight resistant strains of American Chestnut and to develop blight resistant hybrids. A number of studies have evaluated performance of American Chestnut planted on abandoned coal strip mines, both to evaluate the resistance of hybrids to Chestnut blight and to determine their potential use for reclamation. A related study at the UT Forest Resources Research and Education Center in Oak Ridge is evaluating the performance of native trees, including American Chestnut, on quarry spoils. The study is examining the effects of overburden preparation, response of trees to nitrogen fertilization and liming, and the success of pioneer vs later successional trees. Effects of the treatments on ecosystem processes such as changes in soil chemistry and photosynthetic rates are being documented.

Shingle Oak (Quercus imbricaria)

As its name reflects, Shingle Oak has a long history of use for making shingles. Early French colonists in Illinois found that the wood could be split into thin sheets and was also resistant to decay. The distribution of Shingle Oak is centered in the Midwest extending south to Tennessee and Arkansas and east to Pennsylvania and Maryland. In Tennessee, it is most common in the central portions of the state.

The oblong to lance-shaped, dark green leaves have a short bristle tip. Three Shingle Oaks are present in the Oak Collection near the Arboretum’s Program Shelter. They are readily recognized at this time of year because the dark green leaves have yet to change color. As is true for other members of the Red Oak group, the small brown acorns require two years to mature .

Japanese Cedar (Cryptomeria japonica)

Late November to Early December

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.

Japanese Larch (Larix kaempferi)

Ginkgo (Ginkgo biloba)

Red Maple (Acer rubrum)

Chinese Quince (Pseudocydonia sinensis)

Chinese Parasol Tree (Firmiana simplex)

Chinese Mountain Ash
(Sorbus koehneana)

Harry Lauder's Walking Stick
(Corylus avenella) 'Contorta'

Dawn Redwood (Metasequoia glyptostroboides)

Sycamore (Plantanus occidentalis)

American Chestnut (Castanea dentata)

Shingle Oak (Quercus imbricaria)

Japanese Cedar (Cryptomeria japonica)