Pike CNHI - Pennsylvania Natural Heritage Program

Vegetation
The interaction of geology and climate produces the pattern of vegetation expressed on the landscape.
Vegetation provides several critical functions in the landscape including the regulation of biogeochemical
cycles (water, carbon, and nitrogen), soil formation, and wildlife habitat. The classification of vegetation
communities typically revolves around the dominant species, habitat, and their growth form. Discussion
of vegetation communities in this report is divided between terrestrial forested communities and wetland
communities. Boundaries between community types in the field are generally less distinct.
Forest Communities
Pike County is located in the Glaciated Section of the original oak-chestnut forest region (Braun 1950).
The oak-chestnut forest extended from southern New England to northern Georgia. Oaks, and formerly
chestnuts, are the tree species used to characterize the forest. Nothing remains of the original primary
vegetation because of the demise of the chestnut from the chestnut blight caused by the parasitic fungus
Endothia parasitica introduced to America in 1904. The forest of this region is now called mixed oak
forest (Oplinger and Halma 1988, Monk et al.1990). Because of logging, much of the reproduction of
oaks has been as sprouts from the stumps so that the forest is also known as “sprout hardwoods" (Braun
1950). These forests have been logged in the past for lumber and fuel (Keever 1972) and most of the
forest today consists of even-aged timber between 60 and 100 years old.
White, red, and black oaks are the primary species of the forest. Sometimes these species occur together
but each prefers different moisture and nutrient conditions. White oak does best on the moist soils while
red oak prefers drier, better drained soil conditions; black oak does best on the dry upland slopes.
Common associates include red and sugar maple, black cherry, blackgum, and white pine. Shrubs include
blueberry, shadbush, viburnums, and witch hazel.
On the ridge tops where conditions can be very harsh, chestnut oak is the dominant species. Soils are
shallow, nutrients are usually scarce, and winds and weather can be severe, which can cause the trees to
be stunted as a result. Blackgum, gray birch, huckleberry, blueberries, and mountain laurel are common
associates.
The Allegheny section of the hemlock-white pine-northern hardwoods forest (or simply northern
hardwoods) is found on the Pocono Plateau at the western corner of the county (Braun 1950, Oplinger and
Halma 1988). This forest type is found in various forms from Minnesota to Northern New England and
eastern Canada and as far south as central Pennsylvania. The deciduous portions are usually dominated by
beech and sugar maple while the mixed communities are dominated by hemlock with sugar maple, beech,
and other hardwoods. White pine is a subordinate species now but it was a more common component of
the forest prior to logging. Because of the proximity of the mixed oak forest and the northern hardwoods
forest, species overlap and outliers can be found in either forest type due to aspect, moisture, and soils.
Wetland Communities
Wetlands provide essential habitat for many plant and animal species, as well as valuable ecosystem
services such as water filtration, groundwater recharge and flood control. Wetlands are transitional lands
between terrestrial and aquatic systems. They are communities dominated by water for some part of the
growing season throughout each year. Saturation by water determines the soil development, which in turn
influences the type of plants and animals using that habitat. Wetlands differ regionally based on
topography, geology, climate, hydrology, vegetation, and human influences (Stewart 2001). Typical
plants found in wetlands include sedges, grasses, ferns, shrubs, and some trees. The ecological character
of a wetland is heavily influenced by local soil type, disturbance history, bedrock composition, and
hydrologic regime. Types of wetlands range from open marshes that are continuously flooded, to forested
seeps where groundwater saturates the surface only when heavy precipitation raises the water table.
Pike County Natural Heritage Inventory – Natural History Overview / 7