Oconaluftee, GSMNP   Jess Riddle
  Mar 19, 2007 09:07 PST 


Richland Mountain juts south from the central portion of the Smokies'
main divide, and separates the main stem of the Oconaluftee River from
Bradley Fork. In the early 1900's, the confluence of those two
streams hosted a logging town called Smokemont, and many families
farmed the surrounding coves and the flats along the river to the
south. The National Park Service converted Smokemont to a campground,
and halted logging in the watershed down to where the river flows onto
the Cherokee Indian Reservation. Cherokee, NC now caters to tourists
more than any other town along the park's edge in North Carolina, but
that entertainment oriented development is largely confined to the
banks of the Oconaluftee River. US Highway 441 facilitates that
development by paralleling the river through the reservation and the
park to the mountains' crest and descending the other side of the
Smokies to Gatlinburg, TN.

The river forms a natural travel corridor within the park since it
flows straight along a major northwest-southeast fault line for most
of its length. On the south side, tributaries drain northeast off
Thomas Divide, a long ridge that stays around 5000' elevation for most
of its length and defines the western edge of the Oconaluftee
watershed. On the other side of the fault, streams drain south off
the main crest of the Smokies or Richland Mountain directly into the
Oconaluftee. Across Richland Mountain, the main ridges fork more, so
streams follow a variety of aspects to reach Bradley Fork on their way
to the Oconaluftee. While the entire watershed contains rugged
topography typical of large mountains, upper Bradley Fork presents an
especially harsh landscape as hinted at by the names of the streams in
the area: Frowning Rock Prong, Gulf Prong, Washout Branch, and Chasm
Prong. That area of steep slopes, narrow ridges, and incised
drainages correlates to bedrock of the Anakeesta Formation composed
primarily of acidic slates. The area's high elevation ensures
abundant precipitation, which combines with the steep slopes to make
the streams prone to flash floods.

Not surprisingly, with easy access and major tourisms centers nearby,
the Park Service has developed the Oconaluftee watershed more than
most other sections of the park. In addition to the large campground,
Oconaluftee features a visitor center complete with a living museum, a
reconstructed farm meant to demonstrate how many people lived in the
lower part of the valley in the early 1900's. Just up the valley from
the visitors center, Mingus Creek extends the historical education
opportunities with a restored water-powered grist mill, and serves as
the lowest entry point to a web of trails traversing the watershed.
Most of the trails follow low ridges or streams up to the large ridges
that bound the watershed and tie-in with longer trails on them. Some
of the trails follow old road-beds that provided access to farming
areas or railroad grades that accessed the watershed's rich timber
reserves. Those railroad operations left little of the original
forests for the trails to traverse.   Fragments of the original forest
only survive in the main watershed on the upper slopes of Thomas
Divide, along one fork of Collins Creek, at the very top of the
watershed, and on a few dry, south-facing slopes. However, thousands
of acres of untouched forests still grow on the steep slopes of upper
Bradley Fork.

Red spruce, yellow birch, and rosebay rhododendron dominate those
forests. On the highest ridges, fraser fir and mountain ash mix into
the canopy, and the understory may shift to more Catawba rhododendron
or lack rhododendron entirely. The latter areas tend to have a better
developed herbaceous layer with sedges sometimes dominating and witch
hobble in the understory. Some ravines within the spruce forest also
have well developed herbaceous layers with an abundance of ferns and
umbrella leaf, yellow buckeye replacing red spruce in the overstory,
and mountain maple dominating the understory.

At slightly lower elevations, and especially along the western edge of
the Oconaluftee watershed, northern red oak dominates the ridges and
upper slopes. The abundant precipitation associated with the high
elevation keeps even ridges somewhat moist, so the red oaks can often
reach about three feet in diameter; however, the exposed positions of
the red oak dominated forests keeps the canopy well under 100' high.
Red maple often makes up a significant proportion of the overstory
also, and American chestnut was once an important member of the
community. Beeches and white oaks may also be locally abundant, but
the beech are rapidly declining form the impacts of beech bark
disease. Underneath them, striped maple often dominates the midstory
and the azaleas often outnumber the evergreen rhododendrons. The lack
of a dense understory and adequate moister supply allows herbaceous
species to reach moderate coverage and diversity.

Moving down the watershed, rainfall decreases and the ridges become
noticeably drier. Northern red oak and red maple can still dominate,
but they tend to do so on ridges that slope to the east or north or
that are sheltered by higher surrounding ridges. On those sites,
chestnut oaks still mix into the overstory, and rosebay rhododendron
with an upright growth form usually forms a continuous, evergreen
understory that precludes most herbaceous species. On other ridges
below 4000' elevation, white oak and chestnut oak dominate, and the
driest condition favor scarlet oak. Pitch pine mixes in with scarlet
oak on some ridges and mountain laurel typically forms a continuous
shrub layer. Lack of light, soil moisture, and acidic soils limit
herbaceous growth in those forests, but galax can still hide much of
the forest floor at some sites. On slightly less austere ridges below
2500' elevation, other species can mix into the canopy including black
oak, southern red oak, and mockernut hickory.

Settlers chose more moist sites in that elevation range, especially
flat sites along the Oconaluftee itself, for agriculture. The Park
Service maintains a few of those sites as open, grassy fields, but
most have reverted to forest. Tuliptree has had by far the greatest
success in reclaiming the fields, but black locust grows scattered
amongst them at some sites and black walnut has spread a short
distance from some old homesites. Shrubs and sampling generally
remain sparse underneath the tuliptrees, but buffalo nut has formed a
continuous shrub layer on a few sites.

Throughout the watershed, tuliptree dominates along the streams below
3500' although not to near the same extent it does on the old farm
land. Along the streams, black birch and yellow birch also mix into
the canopy, and sycamore and hemlock are locally important; however,
hemlock is not nearly as prevalent as in many other sections of the
park. Rosebay rhododendron consistently occupies the understory and
often extends up slopes into adjacent forests.

Moving upslope from the streams into north and northeast facing coves,
forest diversity and productivity increase dramatically. Those coves
consistently feature high canopies (over 120'), diverse herbaceous
layers, and open understories. Many coves lack shrubs entirely,
although hydrangea may be locally abundant, leaving saplings of
shade-tolerant overstory species, most commonly silverbell and yellow
buckeye, as the primary understory. Similarly sparse midstories also
include silverbell and locally striped maple or hophornbeam.
Overstories may follow the pattern of lower canopy layers and
currently exhibit little diversity, or they may contain a mixture of
several hardwood species. In coves with broad, gentle bottoms,
tuliptree often excludes all other species from the canopy except
black locust. On steeper or colder sites, basswood, sugar maple,
silverbell, black birch, and white ash all mix with a limited number
of tuliptrees to form the overstory. Grape vines, often over four
inches in diameter, frequently tie together all of the canopy layers,
and may be accompanied by Duthcmans pipe vine.

ENTS has spent relatively little time exploring the Oconaluftee
section of the park, only about a dozen days looking at the forests.
Other parts of the park contain far more uncut forest, and Big Creek
has been seen as the premier area for second-growth hardwoods, so
visiting Oconaluftee has not been a priority. However, we have
recently realized that the north facing coves in the area are
consistently productive, and hardwood growth rates may rival those
found in lower Big Creek. Descriptions of several recent trips to the
area have not yet been posted to the listserve.

The lack of old-growth at low to mid elevations makes trees of
exceptionally large diameter rare in the area; hence, we have not
measured enough large trees to compute a Rucker Girth Index. A few
trees with notable circumferences that have been located include: a
potential national champion yellow buckeye with a circumference of
18'7", bitternut hickory 11'1", northern red oak 17'3", and tuliptree
23'0" cbh.

Rucker Height Index: 152.9'
Tuliptree 177.3'
Black Locust 171.8'
Eastern Hemlock 156.2'
Sycamore 155.8'
White Ash 148.6'
Cucumber Magnolia 147.1'
White Basswood 144.7'
Northern Red Oak 144.3'
Beech 142.6'
Black Cherry 140.9'

The Rucker Index is the third highest known in the eastern US after
the Cataloochee and Big Creek sections of the Smokies. Of the trees
contributing to the index, only the hemlock grows in an old-growth
forest. The tuliptree, locust, sycamore, ash, cucumbertree, northern
red oak, and beech were all located this year, suggesting many more
tall trees remain to be found in the area. The watershed now contains
the tallest known individuals of black locust, black cherry, Alleghany
serviceberry, and fraser magnolia, and tuliptree has been confirmed
over 170' tall at six sites in the watershed.

Any additional comments from others familiar with this section of the
Smokies would be appreciated.

Jess Riddle