A predominant feature of trees in the winter landscape is the bark. While bark doesn’t receive much attention most of the year, it is much easier to see in winter without the presence of leaves and can be quite fascinating upon closer inspection.
What is Bark? | Patchwork | Peeling | Smooth | Furrowed | More Information
What is Bark and What Does it Do?
Bark consists of living and dead plant cells present at the periphery of plant stems. Bark is a distinctive characteristic of woody plant species and can be as unique to a tree as its leaves.
Bark has similar functions for most trees. The primary role of bark is protecting the inner living cells from fire, predation, and other threats. Some species of trees, such as bur oak (Quercus macrocarpa) have bark that is particularly resistant to fire. Other trees have bark with thorns (honeylocust or Gleditsia triacanthos) that protect the tree from animals.
In addition to protecting trees, bark is utilized for other purposes. In the rainforest, epiphytic plants, like orchids, anchor their roots into the bark of trees. Many animals and insects use bark as hiding places or habitats. Humans have used bark in various ways for centuries. Bark has been used to make canoes, baskets, clothing, medicines, and dyes. The popular spice cinnamon is obtained from the bark of several tree species from the genus Cinnamomum. The cork oak is the primary source of wine bottle stoppers and other uses. Today, bark is widely used by homeowners for mulching landscape beds and paths
The Diversity of Bark
The color and texture of bark is as diverse as the various tree species themselves. Rainbow eucalyptus (a tropical tree) is noted for having almost all colors in its bark. There are also several tree species with colorful and attractive bark for Midwestern landscapes. While you are out and about this winter season, glance at a few of the trees you pass. The patterns, textures, and colors of bark are worthy of a second look.
Patchwork Bark
Sycamore (Platanus occidentalis) bark consists of patches of green, gray, white, and tan that are randomly pieced together like a scrappy quilt. In winter, the strikingly light-colored bark on sycamores can be seen from a considerable distance in urban forests and natural areas.
A similar patchwork of colors can also be found on the bark of older lacebark pines (Pinus bungeana), or stewartias (Stewartia koreana). While it may require some effort to find these smaller trees for sale in your area, they make great additions to the landscape.
| Common Name | Scientific Name | Bark Description |
|---|---|---|
| Corneliancherry Dogwood | Cornus mas | patching, flaking on mature stems; grey brown |
| Hawthorn | Crataegus viridis | brown to silver gray patches flake off to reveal orange |
| Lacebark Pine | Pinus bungeana | irregular patches of green, white, and brown |
| Scots Pine | Pinus sylvestris | older branches and trunk with patchy, scaly bark in grayish or reddish brown |
| Sycamore | Platanus occidentalis | younger branches with patches of green, gray, white, and tan |
| Stewartia | Stewartia koreana | patchy, flaky; grays, browns, orangish-brown |
| Lacebark Elm | Ulmus parvifolia | patchy pieces flake off to reveal trunk mottled with gray, green, orange, and brown |
Peeling Bark
Walking in the woods, it is easy to recognize the flaky, gray/taupe strips of shagbark hickory (Carya ovata). This Iowa native is an excellent, long-lived landscape tree for sites with plenty of space.
Another popular landscape tree with peeling bark is the river birch (Betula nigra). The river birch has peeling cream, tan, or pale peach colored bark. Trees are often sold with several trunks, allowing you to see more attractive bark and creating a distinctive appearance in the landscape. River birches perform best in moist, slightly acidic soils.
A smaller tree with peeling bark is the paperbark maple (Acer griseum). It has smooth, cinnamon-colored bark that peels off in paper-sized sheets. Paperbark maple does best in sheltered locations in central and southern Iowa.
| Common Name | Scientific Name | Bark Description |
|---|---|---|
| Paperbark Maple | Acer griseum | smooth, cinnamon colored sheets peeling off in papery thin layers |
| Yellow Birch | Betula alleghaniensis | smooth amber colored bark peeling off in papery sheets |
| River Birch | Betula nigra | papery sheets peel off in colors of cream to cinnamon brown |
| Paper Birch | Betula papyrifera | smooth papery, white bark peels off in thin curling sheets |
| Shagbark Hickory | Carya ovata | plates of bark peel in long strips giving trunk a shaggy appearance |
| Redbud | Ceris canadensis | mature bark develops flaky pieces that revel reddish color underneath |
| Turkish Filbert | Corylus colurna | pale to gray brown bark flakes off to reveal brown or orange-brown underneath |
| Seven Sons Flower | Heptacodium miconioides | tan bark peels off in thin sheets revealing cinnamon inner bark |
| Eastern Red Cedar | Juniperus virginiana | brown (sometimes reddish brown) bark peels in long thin strips |
| Amur Maackia | Maackia amurensis | smooth amber to brown to copper bark curls back creating irregular patches |
| Dawn Redwood | Metasequoia glyptostroboides | reddish brown bark peels off in thin vertical strips |
| Ironwood | Ostrya virginiana | gray-brown bark peels off in long strips free at both ends |
| Scots Pine | Pinus sylvestris | younger branches with orangish to orangish-brown smooth, papery bark peeling off in sheets |
| Ninebark | Physocarpus opulifolius | older stems peel with papery pieces in gray-brown |
| Black Cherry | Prunus serotina | mature, older bark flakes off in patches; gray-black |
| Pekin Lilac | Syringa reticulata subsp. pekinensis | papery sheets of coppery to amber bark peel off especially on younger branches |
| Baldcypress | Tasodium distichum | reddish brown bark peels off in thin vertical strips |
Smooth Bark
Several trees, such as beech (Fagus sylvatica) and cherry (Prunus) are noted for their smooth bark. Both trees perform best in protected locations in the southern half of Iowa.
Japanese tree lilac (Syringa reticulata) is a more cold hardy selection suitable for all of Iowa. It has smooth reddish-brown bark. It is also smaller than many of the trees listed above, therefore, it can be planted closer to buildings. Other options for smooth gray bark, are hornbeam (Carpinus species) and serviceberry (Amelanchier species).
| Common Name | Scientific Name | Bark Description |
|---|---|---|
| Striped Maple | Acer pensylvanicum | smooth bark with prominent green and white vertical stripes |
| Serviceberry | Amelanchier | smooth gray to silver-gray bark with vertical striations |
| Hornbeam | Carpinus | smooth gray, older branches and trunk resemble muscles |
| Tatarian Dogwood | Cornus alba | young stems blood red (develops in winter); color varies in intensity by cultivar |
| Silky Dogwood | Cornus amomum | young stems reddish purple; color varies in intensity by cultivar |
| Gray Dogwood | Cornus racemosa | young stems reddish brown; color varies in intensity by cultivar |
| Redosier Dogwood | Cornus sericea | young stems attractive red, some cultivars are orangish yellow (develops in winter); color varies in intensity by cultivar |
| Yellowwood | Cladrastis kentukea | smooth gray |
| Beech | Fagus sylvatica | smooth gray |
| Quaking Aspen | Populus tremuloides | smooth, greenish to cream colored (older wood is dark brown and furrowed) |
| Black Cherry | Prunus serotina | Young branches are shiny, smooth, and reddish with prominent lenticels |
| Japanese Tree Lilac | Syringa reticulata | glossy brown (sometimes reddish brown) |
Furrowed bark
Black walnut (Juglans nigra) and Kentucky coffeetree (Gymnocladus dioicus) display coarse, deeply furrowed bark in the winter months. The gray ridges and black furrows are rugged looking and provide a stark textural contrast in the winter landscape.
| Common Name | Scientific Name | Bark Description |
|---|---|---|
| Hackberry | Celtis occidentalis | older stems furrowed, younger develop wart-like projections |
| Kentucky Coffeetree | Gymnocladus dioicus | rough, scaly, furrowed, gray-brown |
| Black Walnut | Juglans nigra | deep narrow furrows create ridges in a roughly diamond-shape |
| Eastern Cottonwood | Populus deltoides | mature trunks have deeply furrowed, light grey, corky bark |
| Bur Oak | Quercus macrocarpa | deeply furrowed; corky |