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Join Us for the
14th Annual
York/Rock Hill
Christmas Bird Count
20 December 2003
(Please note date change. Click on the link above for more information.)

SMOOTH SUMAC SHINING
IN THE WARM WINTER SUN

At Hilton Pond Center, deciduous trees have slowed their metabolisms to a crawl, and most have dropped their summer foliage to reveal bare branches. Although a few oaks still retain dead, leathery leaves, these too will drop as gusty winds finally twist leaf petioles from their twigs. Just two months ago the landscape was filled with the splendor of fall colors, but by now in mid-December nearly all our local vegetation is brown or gray--except for the fruit of a particularly vigorous Smooth Sumac that has held its color longer than most. Against a bright blue winter sky, the berries of this shrub are so brilliantly red they take one's breath away.

All text & photos © Hilton Pond Center

Despite this wondrous display, sumacs and their relatives in the genus Rhus are often under-appreciated. Some are held in great disdain and a few cause serious problems for people susceptible to dermatitis. Particularly pesky is Rhus radicans/R. toxicodendron, a taxonomically challenging plant (or plants) with the common name of Poison Ivy/Poison Oak. We sometimes call Poison Ivy the "morning-after plant" because that's when you start to realize you had an undetected encounter with it the day before. Sooner or later, almost everyone will develop a rash from Poison Ivy, although it may take repeated contacts over many years before a individual's sensitivity threshold is reached.

In the Piedmont, Poison Ivy/Poison Oak typically grows as a ground vine or clings to trees; holding on to bark with its adventitious roots, an old Poison Ivy vine can sometimes attain diameters of 6" or more as it climbs toward the canopy. Its compound leaf is only thrice dissected. The shrubby Poison Sumac, Rhus vernix, has a few more leaflets--usually 7-13--and may reach 15 feet in height. As its name implies, it is not a plant you want to embrace; all parts contain urushiol--the same skin irritant found in Poison Ivy--and induces the most serious rashes of all our toxic plants. Although it grows from Maine to Florida, its chief habitat is undisturbed bogs and swamps, so it's unlikely to be encountered by the typical nature walker. But enough of these dermatologically displeasing plants; let's talk about sumacs that DON'T cause rashes before everyone's skin starts to itch.

Like Poison Sumac, our other three most common sumacs also occur as shrubs, growing principally in old fields and on fence rows, and sometimes forming dense thickets along roadsides. Since each of these three--Smooth, Staghorn, and Winged Sumac--sprout energetically where people don't plant them, they are sometimes considered "weed trees" and often succumb to grazing by lawn mowers and bush axes. Unlike most property owners, we cherish our Hilton Pond sumacs, in part because they are pioneer shrubs that invade disturbed areas and also because they quickly grow large enough to provide food or cover for a variety of wildlife.

Sumacs make up a major subgroup of the Cashew Family (Anacardiaceae). Many of their relatives--including the Cashew tree--are tropical. All our sumacs have compound leaves (above right); in some, as many as 31 leaflets make up a single leaf.

Staghorn Sumac (Rhus typhina) is the largest of our Southeastern sumacs, sometimes reaching 30 feet in height in the mountain counties in North Carolina; in South Carolina it has been reported only from Greenville County. Its smaller branches and petioles—the stem-like structures that attach the leaves to branches—are covered by velvety hair, and the underside of the leaves are usually whitish and downy. Look for dense, fast-growing colonies of this plant in Interstate highway medians at higher elevations in the Carolinas.

Smooth Sumac (R. glabra) is quite similar to Staghorn Sumac, but as its name suggests, its twigs and heavily serrated leaves are not hairy. Smooth Sumac--also called Shining Sumac or Common Sumac--is a medium-sized shrub, reaching no more than 20 feet high; it grows across the Carolinas except in the Coastal Plain. Like other sumacs, in mid-summer it makes terminal clusters of yellow-green flowers (above left) that, when pollinated, make the bright red berries illustrated in the top three photos on this page.

Winged Sumac (R. copallina)--our smallest common species, is nearly ubiquitous in open places from the mountains to the sea. Typically it is much shorter than its maximum height of 10 feet. This delightful little shrub gets its name from small "wings" protruding from the main central leaf vein between bases of the leaflets; these are remnants from when sumacs had entire--not compound--leaves. Winged Sumac has densely pubescent hairy stems with prominent V-shaped leaf scars.

We should mention that two other species--Fragrant Sumac, R. aromatica and False Poison Sumac, R. michauxii--also can be found in the Carolina Piedmont. The former occurs uncommonly in rocky woods where igneous rocks protrude from the soil; a six-foot shrub, it flowers in spring before its leaves open. Originally and more-aptly named R. pumilla (Dwarf Sumac) by early botanist Andre Michaux--R. michauxii is the smallest and rarest of our native species; it occurs in only a few counties and reaches diminutive heights of less than one foot.

At Hilton Pond Center, one of our favorite attributes of Smooth and Winged Sumacs is those large clusters of red fruits they produce each fall. Each cluster resembles an inverted bunch of miniature red grapes, and it sometimes attracts the attention of birds and small mammals. Even so, animals seldom eat many of the semi-flattened disc-like berries until harsh winters eliminate other natural foods. People who enjoy wild edibles use fresh sumac berries to make a beverage that is high in Vitamin A, tastes a little like lemonade, and can be quite tart; the berry's acidity may explain why few birds or mammals make sumac their first choice for winter dining.

Sumacs do play a role in feeding wildlife, however; their twigs are significant as winter browse for deer and rabbits, both of which keep sumacs pruned back even more efficiently than do lawn mowers. In regions where deep snow covers grass and other herbaceous growth, emergent sumacs provide a semi-succulent and nutritious source of plant proteins and sugars for hungry mammals.

Over the past two decades, vegetational succession has turned the land around Hilton Pond from old farm to woodland, so our sumacs have become increasingly scarce. Where once they occurred all along the trail, they now grow only at the edges of small meadows we maintain to encourage such diversity. By this time of year, our remaining Smooth and Winged Sumacs seem as lifeless as all the other local trees and shrubs. Their deep green leaflets turned crimson back in October (above left), and for the most part their fuzzy seeds have traded their own brilliant color for a drab and dingy brown (below).

The sole exception at Hilton Pond Center is one spectacular Smooth Sumac that has no sense of calendar and still shines brightly in the warm winter sun. We thank it for its tardiness.

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SPECIES BANDED THIS WEEK:
American Goldfinch--13
House Finch--7

* = New species for 2004

WEEKLY BANDING TOTAL
2 species
20 individuals

YEARLY BANDING TOTAL (2004)
68 species
1,953 individuals

BANDING GRAND TOTAL
(since 28 June 1982)
124 species
45,258 individuals

All text & photos © Hilton Pond Center

NOTABLE RECAPTURES THIS WEEK
(with original banding date, sex, and current age)