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Perhaps of more interest to
visitors today is the other half of the mountain-building story,
their gradual destruction. The slow, steady forces of wind, water,
and chemical decomposition have reduced the Blue Ridge from
Sierra-like proportions to the low profile of the world's oldest
mountain range. The almost constant wind that blows across the
exposed ridge tops of the Appalachians plays an important role in
the weathering and eroding processes.
Summer thunderstorms bring
torrents of rain. In the winter, freezing and thawing water in
crevices brings occasional rockslides that bear witness to the
erosional processes in these mountains. Occasional catastrophic
events like floods, hurricane force winds, blizzards and ice storms
can change the face of the mountains overnight.
The geological history of the
mountains is a determining factor in all of the flora (plant life)
and fauna (animal life) protected in the park. Plant and animal
communities can change dramatically depending on the direction a
particular ridge is facing, the elevation, soil type, and exposure
to the elements.
The eastern edge of the Blue Ridge is consistently
more rugged and steep than the western edge due to the direction of
uplift during the creation of the mountains. Because of this, the
eastern slopes of the Blue Ridge have more rugged river drainage,
evidenced by Linville Gorge (Milepost 316) and Rockcastle Gorge
(Milepost 169).
Diversity of habitat and diversity
of species await the observant visitor to this long, linear national
park. Diversity is the key word in an understanding of the ecology
of the Appalachian mountains. Multiple and overlapping habitats,
exceptional examples of forest communities, and locally wide
variations yield a huge diversity of flora (plant life) and fauna
(animal life) on the Parkway.
Park biologists have identified 1,250
kinds of vascular plants; twenty-five of these are rare or
endangered. Four rare or endangered animals have also been
identified on Parkway lands.
The reasons for this wide diversity
are numerous. Elevation is a key factor, with Parkway lands as low
as 650 feet above sea level at James River (Milepost 64) and topping
out at 6,047 feet at Richland Balsam (Milepost 431). The Parkway is
also oriented on a north-south axis with its two ends almost 500
miles apart.
Combining these two factors, the Parkway contains
habitat as diverse as one may find traveling from Georgia to
Newfoundland. Another factor is that many ridge tops may bear the
full force of wind, sun, and severe weather conditions, while
protected coves are dark and moist. These factors contribute to the
diversity and interrelationship of species.
Beginning at the Parkway's lowest
elevations and climbing up to the highest, visitors will notice
numerous transitions among a variety of forest types. At lower
elevations, the oak-chestnut forest dominates Parkway lands with a
variety of oak trees composing the forest. In remote, sheltered cove
forests, you may find dozens of varieties of species, and some of
the remaining virgin timber that was inaccessible to loggers earlier
in the century.
Higher up on the mountains,
northern hardwood forests remind many people of those in New
England. Beech, Birch, or Buckeye may dominate depending on other
characteristics of the habitat. At the highest Parkway elevations,
it is the Spruce-Fir forest that crowns the ridge tops and mountain
peaks. In front of advancing glaciers, remnants of seeds normally
germinating in Canadian forests found a habitat in which to grow.
Trees enrich our lives throughout
the year. However, it is only during the fall that they wave
flamboyant foliage that seems to demand our attention. The intensity
of their announcements depends upon weather conditions. Bright sunny
days and cool, but not freezing, nighttime temperatures are
requirements for a vivid autumn show. If there is an early frost,
the leaves are likely to become brown and drop. In autumn,
chlorophyll, the green coloring agent in leaves that makes
photosynthesis possible, begins to decrease.
As chlorophyll fades, other colors
such as red, orange and yellow appear. Carotenes and xanthophylls
are pigments that produce the lively yellows, golds and oranges of
autumn leaves. These pigments are present in summer but they are
hidden by the green of chlorophyll. Only when chlorophyll production
stops, do they show their presence. The scarlet, rust and purple
leaves are caused by anthocyanin pigments.
Unlike the carotenes and
xanthophylls, these pigments are not already present in the leaves
but are synthesized in the leaf after chlorophyll production stops.
When chlorophyll production stops, so does the flow of water and
glucose between the leaves and the tree. A layer of cells called the
abscission layer, develops to block the flow. Some glucose will be
trapped inside the leaf and it will change to anthocyanin pigments
with the help of certain weather conditions.
The Blue Ridge Parkway has many
scenic attractions, not the least of which is its variety of birds.
For birding enthusiasts, the Parkway offers a never-ending supply of
beautiful birds, from the American Bittern to the Whip-poor-will.
The annual autumn hawk migration down the Blue Ridge can be
spectacular. Birds seen in all seasons include Cardinal, Carolina
Chickadee, Red Tailed Hawk, Tufted Titmouse, Pileated and
Red-bellied Woodpecker, and the Carolina Wren.
The Blue Ridge Parkway is a
wildflower lover's paradise, offering a huge variety of native
species during spring, summer, and fall. Depending on your
elevation and north/south orientation, some species can be found
blooming over a considerably long period of time. The following list
is a highlight of some of the most popular wildflowers, their months
in bloom, and places along the Parkway where you can find them.
Photograph them, sketch them, or simply enjoy the view, but all of
the park resources are protected - leave them for others to enjoy.
The Blue Ridge Parkway is a
wildflower lover's paradise, offering a huge variety of native
species during spring, summer, and fall. Depending on your elevation
and north/south orientation, some species can be found blooming over
a considerably long period.
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