A degree of romance or mystique surrounds the cove hardwood forest. The name was used as early as 1905 in professional forestry literature, but was probably coined much earlier, perhaps in the days of settlement.
The coves share all of their predominant trees with the neighboring plant communities, and no common animal or plant is restricted to cove forest. The key to its recognition is variety, particularly in the make-up of the canopy, the name given to the roof level of any woodland. Cove forest is not restricted literally to topographic flats and hollows; it may also occur on steep slopes, where soil moisture conditions are suitable.
In its best development, cove forest may sustain 20-25 tree species tangling branches far overhead. Look for white ash, sugar maple, magnolia, American beech, silverbell, and basswood. If most of these are present, with or without buckeye, holly, yellow birch, and hemlock, you are being treated to cove hardwood scenery.
Oaks, hickories, red maple and yellow-poplar (tulip tree) will also be present, but these widespread species are not really useful in settling the question. One often workable rule of thumb is the presence of yellow-wood, but this small tree is absent from the cove hardwood forest community in many parts of the park.
Many of today’s typical cove hardwood trees have also been found as fossils in rocks of Cretaceous age in the eastern United States. This match up—and the recognition that the southern mountains have been continuously available for land plant growth since Dinosaur Days—has given plant geographers much food for thought. Cove forest is now plausibly regarded as a very ancient mixture of species. Probably, it was the ancestor of several other widespread forest communities. Perhaps it was the haven of refuge sought by many plants and animals during the Pleistocene glacial period. Its significance today is its wealth of species composition and its heritage—millions of years of forest evolution. We are fortunate that significant stands of this forest type survive uncut in the Great Smoky Mountains.
A great benefit of these rich, lush forests for hikers is the refreshing coolness they afford on hot summer days. Many people have described them as “green cathedrals” because of the coolness, rest, and peace they seem to engender.
When the yellow-poplar seeds into an abandoned farm field it means that the field could eventually become a cove forest. But the yellow-poplar needs the company of a dozen other species to form true cove forest.
The yellow-poplar grows fast and straight. Its bark has white-sided ridges.
Cove forest has less moss cover than the spruce-fir forest, but it boasts more kinds of mosses. The abundance of trees, flowers, and lower plants is produced by ideal moisture and a temperate climate.
Forest Openings: The Balds
Most mountains show mosaic patterns of vegetation noticeable at a distance, or on scenic postcards. In the Smokies high country this zoning is conspicuous. These mountains rival the Rockies for all such contrasts, except for naked rock above timberline.
There is no climatic treeline—roughly an elevation above which trees cannot survive—in the Smokies. But two important treeless communities, called “balds” by the early settlers, give this above-timber effect here.
The baldness is not that of bare rock, but rather a mountain-top interruption to the forest cover. The two types, grass balds and heath balds, are alike only in appearance from a distance, and in their preference for mountain summits.
The Cherokees wove the balds into their religion and folklore. Mountaineers grazed stock on the grass balds and cursed the heath balds as “slicks” or “hells.” Botanists began to publish explanations for these balds a century ago but you can still formulate your own theory because there are no agreed-upon answers. The more careful the study, the more puzzles arise. But the key in both cases seems to be disturbance, the successive destruction of generations of tree seedlings.
For heath balds the most obvious tree-killing agent is fire and so fire was advanced as an explanation for their origin. Shrubs can burn to the ground and grow back quickly, sprouting from their roots. Mountain laurel, rhododendron, blueberry, huckleberry, and sand myrtle all do this. It was theorized that where fire knocks out the tree layer, there are the heath balds. But the rub is that some balds show no signs of fire and yet are not nursing young trees.
Landslides eliminate trees, and winter winds may also discourage tree growth. Heath balds persevere where slopes are steep, soil is peaty and acidic, and the elevation tops 1,200 meters (4,000 feet).
Today the grass balds are a mosaic of shrubs, grasses, and young trees. Open patches may be clearly dominated by grasses but the total number of plant species present on grass balds is greater than the number present on heath balds.
Explanations of the origin of grass balds have been much debated but no theory has been accepted for them all. We do know that most grass balds were used as high elevation pastures in the 1800s and early 1900s, and when the park was established the grass balds were more open than today. Most Southern Appalachian grass balds are being quickly invaded by trees and shrubs. The National Park Service is developing plans to keep two Smokies balds open. Despite their appearance, grassy balds have no floristic relation to true alpine or arctic tundra vegetation.
The sundew, a bog plant common in the far North, persists on one grass bald, near a spring. What look like dew droplets are actually gluey traps for insects, which this carnivorous plant kills and absorbs.
Flame azalea thrives on grassy balds. At Gregory Bald it hybridizes with other azaleas, producing an array of colored flowers that botanists call a “hybrid swarm.”
When settlers grazed stock on the grass balds, many common weeds such as dandelions were introduced. Before settlement deer and elk probably grazed here, and may have helped keep out encroaching trees.
The presence of trout somehow symbolizes wild nature and pristine beauty. Pools such as this one at the foot of Grotto Falls on Roaring Fork, are quiet forest gems that cause the finger of many an angler to twitch uncontrollably.
The Trout’s World
The rays of the early morning sun bombard the tops of the trees spread above the headwaters of Forney Creek. Some penetrate the canopy to make light patches in the lower layers of the forest. But few break through the rhododendron thickets along the stream to illuminate its mossy rocks, its foam, and its clear pools. Down in the darkness beneath overhanging shrubs, hanging in the current near the bottom of a pool, a brook trout waits for the stream to bring it food. With dark mottling along its back, red spots on its olive sides, and pale orange edging on its lower fins, the fish is beautiful. It is also small, about 18 centimeters (7 inches) long, and lean, for it lives in a harsh environment where food is scarce, the water is cold and acidic, and floods and thick ice can scour. This is one of only a few trout in the pool because there is not enough food for many.
The trout fed little during the night and now its hunger is acute. Carefully it watches the rippling surface for insects, spiders, crayfish, salamanders, and worms, or any animal life caught and carried down by the current. But nothing appears. It noses up to a rock where earlier in the summer it had found caddisfly larvae fastened in their tubular little cases made of tiny pebbles. Now none are left on the surface of the rock accessible to the trout. It searches other rocks and eventually finds one caddisfly larva and a small mayfly nymph, flattened against the under side. The trout dashes at a small salamander, which escapes under another rock. Three crayfish also inhabit the pool but they are too big for this particular trout to eat.