Low Gap to Stuart Knob
November, 2001
This documents an inventory of the forest through a 1000 ft (300 meters) change in elevation in the Allegheny Mountain subprovince at near 39° N latitude. Start of the inventory is at Low Gap along Route 33 at an elevation of about 2900 ft (880 meters) in Appalachian mixed forest. It then extends through northern hardwood and spruce montane forest and ends at an outpost of Northern Red oak (Quercus rubra) forest at Stuart Knob and at about 3900 ft (1190 meters) elevation. Except for isolated trees this forest is secondary and ranges from young to young- mature in age. In places individual large trees, possibly dating to the primary forest, are present. Along this traverse available moisture and temperature, as related to topographic position, including aspect, are seen to be an important modifiers of the elevational effect.
The area surveyed at Low Gap is a northwest-sloping hollow which forms a drainage leading to Taylor Run. This steep-sided hollow has numerous seeps, rock outcroppings and abundant large woody debris, which, with the large, mature trees, provides a structurally diverse forest interior habitat. The canopy is dominated by Sugar and Red Maples (Acer saccharum and A. rubrum ), White Ash (Fraxinus americana ), Northern Red Oak, apparently Adelgid-free Canada Hemlock ( Tsuga canadensis ), Yellow and Black Birches ( Betula allegheniensis and B. lenta ), Tuliptree (Liriodendron tulipifera ), Cucumber Magnolia ( Magnolia acuminata ), American Beech ( Fagus grandifolia ) and Black Cherry (Prunus serotina ) . There is also a little American Basswood (Tilia americana ), a few Red Spruce ( Picea rubens ) saplings and an undergrowth of Witch Hazel (Hamamelis virginiana ), Alternate-leaved Dogwood (Cornus alternifolia ), Great Rhododendron (Rhododendron maximum ), Maple-leaf Viburnum (Viburnum acerifolium ) and abundant Striped Maple ( Acer pensylvanicum ) .
The herbaceous ground cover in the dryer areas of the generally moist slope included Beechdrops (Epifagus virginiana), Partridge Berry ( Mitchella repens ), Wood Betony (Pedicularis canadensis ), Northern White Violet (Viola pallens ) , Round-leaf Violet (V. rotundifolia ), White Snakeroot (Eupatorium rugosum ), Foamflower (Tiarella cordifolia ) , Indian Cucumber-root (Medeola virginiana ), Canada Mayflower (Maianthemum canadense), Sweet-scented Bedstraw (Galium triflorum ), an unidentified Clintonia, Mountain and White Wood Asters ( Aster acuminatus and A. divaricatus ), Indian Turnip (Arisaema triphyllum ), Enchanter's Nightshade (Circća quadrisulcata), White Avens (Geum canadense), Wild Ginger (Asarum canadense), White Wood and Upright Yellow Wood Sorrels (Oxalis montana andO. stricta ), Honewort (Cryptotaenia canadensis ), a species of Prenanthes, the sedges Carex digitalis, C. laxiflora and C. plantaginea, the grasses Poa alsodes, Bottle-brush Grass (Elymus hystix ) and Brachyelytrum erectum and the Large Round-leaved Orchid (Habenaria orbiculata ) . Christmas Fern ( Polystichum acrostichoides ) is common, Rock Fern (Polypodium virginianum ) occurs on large rocks, and Rattlesnake Fern ( Botrychium virginianum ) and Intermediate Shield Fern (Dryopteris intermedia ), as well as Shining Clubmoss ( Lycopodium lucidulum ), were observed.
Growing in seeps and along small temporary streams were Fowl Managrass (Glyceria striata ), a jewelweed (Impatiens sp ), Turtlehead (Chelone glabra ), and the sedge Carex scabrata.
Fauna noted were abundant Dusky Salamanders (Desmognathus sp.) and Black-throated Green Warblers (Dendroica virens).
The next station inventoried lies somewhat over a mile (1.6 km) north of Low Gap along Forest Road 146 just west of FR 91, at an elevation of about 3100 ft. (940 meters). The aspect is for the most part south, the forest is young, at least near the road junction and consists largely of Yellow Birch with a heavy undergrowth of Great Rhododendron. Perhaps 500 ft (150 meters) west of the road junction, along FR 146, the forest is more mature and diverse with a canopy of Hemlock, Black Cherry, Cucumber and Fraser (M. fraseri ) Magnolias, Sugar Maple, Northern Red Oak and Tuliptree, and has an undergrowth of Striped Maple, Witch Hazel and Mountain Holly (Ilex Montana ) . New York Fern ( Thelypteris noveboracensis ) is abundant, but other ground cover is sparse. In one place the canopy consists of 40% Tuliptree, 40% Black Cherry, with the rest of Red Maple, Northern Red Oak, Cucumber Magnolia, Yellow Birch and a little Red Spruce. Undergrowth is Beech and Striped Maple. Ground cover here consisted of Indian Cucumber-root, Partridge Berry, Roundleaf Violet, Indian Turnip, Indian Pipe (Monotropa uniflora ), New York and Cinnamon (Osmunda cinnamomea ) Ferns, Ground Pine (Lycopodium flabelliforme ) , Tree Clubmoss (L. obscurum ) and Carex debilis. Northern Red Oak increases substantially up slope. Although some large trees are present, this forest is clearly more degraded— probably as a result of overcutting — than that at Low Gap,as is shown particularly by lack of diversity and sparse ground cover.
Source Walk: 7-21-95
Bear Heaven Campground lies at approximately 3600 ft. (1100 meters) asl on a small mountain spur. The immediate area of the campground is quite flat but the surrounding terrain slopes off in all directions. The canopy here is essentially northern hardwood and consists of large, mature Black Cherry, Beech, Northern Red Oak, Sugar and Red Maples and White Ash, with some trees as large as 3 ft (0.9 meter) dbh. These trees may be 100 years old or older. Striped Maple is abundant, and there are scattered Red Spruce in the understory. Although no Tuliptree was seen, a few were reported to be down slope. There appear to be remains of a few dead American Chestnut ( Castaea dentata ) and Witch Hazel, Minnie-bush (Menziesia pilosa ) and Hobblebush ( Viburnum alnifolium ) form a thin shrub layer. Common Greenbrier (Smilax rotundifolia) and Hispid Greenbrier (Smilax hispida) were the only vines seen. Although the forest here is mature with splendid trees, ground cover is sparse and less diverse than at Low Gap, perhaps as a result of generally rockier and dryer soil. Species recorded were Canada Mayflower, White Wood Sorrel, Painted Trillium ( Trillium undulatum ), Star Flower (Trientalis borealis ), a Clintonia (probably C. borealis), Indian Cucumber-root, Four-leaved Yam ( Dioscorea quaternata ), Clearweed ( Pilea pumila ) stunted Wood Nettle (Laportea canadensis ), Hay-scented (Dennstaedtia punctilobula ), Cinnamon and Marginal Shield Ferns and the grass Brachyelytrum erectum. The first five plants listed are northern species usually associated with cool growing conditions.
Many large blocks of a light gray conglomerate are exposed here and bear a growth of large lush Rock Tripe as well as some Rock Fern on their surfaces. Where flat surfaces of these rocks are near horizontal, they may also have growths of the sedges Carex debilis or Carex brunnescens, with the latter, a northern species, in particular forming dense mats. While mosses are not particularly abundant, Leucobryum glucum is quite common.
Evidence of past forest fires in the form of basal trunk scars is common. However, the general absence of widely spaced individuals of multiply-trunked trees seems to indicate a long return period for these fires.
Although little time could be devoted to fauna, the calls of the Red-eyed Vireo (Vireo olivaceus ) and Hermit Thrush ( Catharus guttatus ) were noted.
This traverse, which extends along FR-91, ranges between 3600 ft (1100 meters) and 3900 ft (1200 meters) elevation and includes roadside as well as forest interior vegetation. In several places the forest was entered for spot inventories. To be most meaningful, species are generally listed in the order in which they are encountered.
The first section of the traverse, extending from Bear Heaven to perhaps a mile northwest, is at essentially the same elevation as Bear Heaven. Species successively encountered, mostly in addition to those already seen at Bear Heaven, were Cucumber magnolia, Upright Yellow Wood Sorrel, Honewort, a muhley grass (Muhlenbergia sp.), Smooth Sweet Cicely ( Osmorhiza longistylis ), Sweet-scented Bedstraw, Wood Nettle, Northerm White Violet, Blue Cohosh (Caulophyllum thalictroides ) White Baneberry (Actaea pachypoda ), White Snakeroot (Eupatorium rugosum ), a species of alienGalinsoga, a species of Jewelweed, Crooked-stem Aster ( Aster prenanthoides), a species of the grass Agrostis, Yellow Birch, Nodding Fescue (Festuca obtusa), Lady Fern (Athyrium filix- femina), New York Fern, Golden Ragwort ( Senecio aureus), Great Rhododendron, Woodland Strawberry (Fragaria vesca), Common Horsetail (Equisetum arvense), Fowl Managrass, Northern Bugleweed (Lycopus uniflorus), species ofSphagnum, Thuidium (Fern) and Hypnum mosses, Hemlock, Northern Swamp Buttercup ( Ranunculus septentrionalis), Mountain Oat Grass (Danthonia compressa ) . At the end of this section a spot inventory was conducted within the forest, which is youthful and has a northern aspect. Canopy species in approximate order of abundance are Yellow Birch, Beech, Sugar and Red Maples, Red Spruce, Hemlock, Black Cherry, and Fraser Magnolia with undergrowth of Mountain Holly and Mountain Laurel (Kalmia latifolia) . Birds noted were Juncos (Junco hyemalis) and Chipping Sparrows (Spizella passerina) . Continuing beyond this point along the road, we successively encountered Partridge Berry, the bulrush Scirpus polyphyllus, Shining Clubmoss, Tree Clubmoss, White Wood and Mountain Asters, Robin's Plantain (Erigeron pulchellus ), Wrinkled-leaf Goldenrod ( Solidago rugosa ), Fringed Loosestrife ( Lysimachia ciliata ), Carex laxiflora, Christmas Fern, Calico Aster (Aster lateriflorus ), Filmy Angelica (Angelica triquinata ) and a single small Summer Grape (Vitis aestivalis ) vine were observed. Now, at an elevation of perhaps 3700 ft (1130 meters), the forest has an open canopy with heavy undergrowth of Rhododendron and tree species much as at the last spot inventory. Here on the shady south side of the road, under overhanging trees, there is a rich community of low plants including beautiful Plume Moss (Ptilium crista-castrensis), Tiered Moss (Hylocomium splendens), the leafy liverwort Scapania nemerosus, and on a wet bank, American Water Pennywort (Hydrocotyle americana ) and blooming Round-leaf Pyrola (Pyrola rotundifolia).
A little over a mile east of Stuart Knob at perhaps 3700 ft (1130 meters) elevation we successively encountered the small spiny tree, Devil's Walking Stick (Aralia spinosa), Wild Rye (Elymus riparius), Panicled Aster (Aster simplex ), Common Speedwell (Veronica officinalis), White Grass (Leersia virginica) and the Haircap Moss (Polytrichum juniperium). Along this section of the traverse we were serenaded by almost incessant and lively songs of Winter Wrens (Troglodytes troglodytes ) punctuated by Sthe more ethereal ones of the Hermit Thrush..
We now entered an area, still with a northern aspect, of essentially montane spruce forest such as is usually found in summit areas well above 4000 ft (1220 meters) but is here at perhaps 3800 ft (1160 meters). The canopy of this forest is almost pure Red Spruce, perhaps little more than 30 years old, with minor Yellow Birch and Hemlock and with an undergrowth of Mountain Maple ( Acer spicatum ), Mountain Holly and Hobblebush. Ground cover is dominantly mosses, the liverwort Bazzania trilobata, White Wood Sorrel and Intermediate Shield Fern. These plants also provide a covering, with Rock Fern, of the many large sandstone blocks present here. There was also a scattering of the mushroomRussula emetica. A little farther on along the road we encountered the first Mountain Ash (Sorbus americana ), although this tree was probably undetected in the spruce forest as well. Also in the general area we noted Interrupted Fern (Osmunda claytoniana ) and in the road opening a Red Admiral Butterfly (Venessa atalanta).
Not far past the spruce forest there is a patch of recently cleared but re -grown forest that extends down -slope toward the head of Condon Run, just beyond the western edge of the Otter Creek Wilderness. Here is more Devil's Walking Stick, a curious, mostly southern species of the Ginseng Family, that occurs at quite high elevations in the Appalachians although it does not extend far north. Here it is associated with Red Elderberry (Sambucus pubens ), Painted Trillium ( Trillium undulatum ) and Drooping Wood Reedgrass (Cinna latifolia), all three northerners, as well as Deer-tongue Grass ( Panicum clandestinum ), Black Cohosh (Cimicifuga racemosa), the sedge Carex intumescens, Sensitive (Onoclea sensibilis ) and Maidenhair (Adiantum pedatum ) Ferns and a species of wild current (Rubes sp.). Curiously also, we find growing together two species of Enchanters Nightshade, the temperate climate (Circća quadrisulcata and the circumpolar speciesC. alpina, which ranges to Alaska and beyond, and is usually confined to high elevations.
The road extends along the crest of the ridge leading to Stuart Knob. The canopy here is again Northern Hardwood, consisting of Beech ( Fagus grandifolia ), Sugar Maple, Black Cherry, Northern Red Oak and Cucumber Magnolia and with Red Spruce in the understory. Here also we noted the first Smooth Gooseberry (Ribes rotundifolium), and again, the Large Round-leaved Orchid (Habenaria orbiculata), a northern species we already found at Low Gap. Farther along the spruce component increases in the hardwoods and there is more Mountain Ash. Some of the Spruce on the south-facing slope are very large, possibly 30 inches (90 cm) in diameter and seem to be survivors of the primary forest that found sufficient moisture, perhaps from colluvial springs. Witch Hazel is prominent undergrowth, the Bulrush Scirpus cyperinus occurs along the road, and Northern Red Oak increases in proportion, until at the base of Stuart Knob, it is the dominant canopy species. Although no attempt was made to ascend Stuart Knob, which rises perhaps 150 ft (46 meters) above the road, it appears that Northern Red Oak forest extends to the top, at least on the south slope. It is likely that on such exposed and relatively dry ridges and peaks Red Spruce was always excluded from the primary forest, which was dominated by Northern Red Oak.
There is much in this traverse that begs explanation, although certain features are clear. First, the forest type contrasts sharply with those of the Valley and Ridge at similar elevations and on similar rock types. Northern Red Oak is here the only oak observed and virtually all species are mesic excluding a few such generalists as Mountain. Laurel and Common Speedwell. While the effect of elevation is readily apparent, considerable tolerance of temperature range is implied by the coexistence of temperate and southern species with those more characteristic of the north and high elevations, a circumstance also noted elsewhere (see our section on White Top Mountain).
The effect of aspect is well illustrated by the occurrence of typical young spruce forest below 3800 ft (1160 meters) elevation only on the north facing slope. The presence of Red Spruce in the understory at all elevations traversed seems to indicate that this species was selectively eliminated by logging and/or fires, was at first unable to regenerate competitively on sites in which it shared dominance with hardwoods, and is making a late recovery by virtue of its shade tolerance. If we exclude the primary forest remnants on the high south-facing slope, on only the north-facing slopes above 3700 ft (1130 meters) was this species able to compete successfully with hardwoods from the start of forest recovery.
A further point of interest relates to air movement. Since virtually the entire forest traversed from just above Low Gap to Stuart Knob lies on slopes or ridge crests, it is unlikely that cold air accumulation by air drainage plays much of a role. Consequently we can assume that the presence of cold climate species—spruce, Mountain Ash. Mountain Holly, White Wood Sorrel, etc. — results from a pure elevational effect. The single exception is the occurrence of some cold-lovers such as Red Spruce, Canada Mayflower and Large Round-leaved Orchid in the north-sloping hollow at Low Gap, which may be attributable to a combination of cold air accumulation and the northern aspect. Since all the forests traversed here lie under 4000 ft (1220 meters) asl, and since they are generally on ridges and uplands, they are not, however, as subject to low temperatures as are communities that lie at similar or even lower elevations in well defined basins surrounded by higher terrain. .
Low Gap to Stuart Knob
7-22-95
Plume Moss.
Low Gap to Stuart Knob
7-22-95 Forest, Young Spruce Forest.
Low Gap to Stuart Knob
7-21-95
Forest, Bear Heaven Camp.