April 17, 2011

Virginia - Shenandoah National Park

Shenandoah National Park, located in the Blue Ridge Mountains of northwestern Virginia, is one of the most famous national parks in the nation. That is probably because it is located just a couple hours drive west of the heavily populated Washington DC-Baltimore area, and just a day's drive from the even more heavily populated New York-Philadelphia megalopolis better known as New Jersey.

Early morning view from the 4,000 foot Hawksbill (highest peak in Shenandoah)

Located on the eastern edge of the middle portions of the Appalachian Range, it is also the highest ridge in the amazing series of folds that make up these mountains. Formed by the collision of North America and Africa, some 450 million years ago, these mountains once rose to Himalayan-like heights of over 20,000 feet! When a rift formed, separating North America, Africa, and Europe, it torn the mountains apart, leaving parts of the Appalachians in Africa (Atlas Mountains in Morocco) and parts of it in Europe (Scottish Highlands). Today, what we see in its peaks and troughs are just the core rocks that folded under the immense pressures of continental collisions.

A series of ridges and valleys in the Appalachians from the air

Shenandoah National Park protects a beautiful stretch of Eastern Deciduous Forests. The diversity of these forests is outstanding, consisting of white oak, hickory, elm, maple, and tulip poplars. Of course, it wasn't always this case. This entire park was clear cut in the 1800's and in 1935, when the park was established, much of it was still barren, while the rest was relatively young second growth.

Oak-Hickory Forest

As much of the land was denuded in the late 1800's and early 1900's, timber and game became scarce and it was difficult to successfully farm in the uplands. Thus, much of it was abandoned. Slowly, the state of Virginia began to reacquire the vacant land. Eventually, in 1926 Congress authorized the creation of Shenandoah National Park. However, there were still about 500 people living within its boundaries, so over a period of 9 years people where either bought out, forced to move, or allowed to stay until they died. By 1935 the park was fully established. Today, it is the ecological gem of the Mid-Atlantic Region!

While the forests recovered quickly with protection from saw and plow, one element of this forest never recovered. Chestnut-blight, brought to the U.S. in 1900, had completely devastated the American chestnut in Shenandoah even before the park was established. It is estimated that chestnuts once composed over 40% of the trees in the forests of the mid-Atlantic and were also among the tallest and largest of all trees in this region. Thus, to lose that component of these forests was a major impact.

American chestnut sprouts from a dead stump
The saplings from previous resprouts have already succumbed to the blight

But, what shocked me when I started hiking around Shenandoah is that the American chestnut still lives in the park. Most of them are very small and generally you find them as sprouts coming out of the base of huge stumps. Apparently, the blight only kills the chestnuts when they reach reproductive age and the dead trunks and roots are pretty resilient. So, after the main stem dies, it will resprout, grow up to a small tree size and then immediately upon producing its first flowers and nuts is reinfected with the blight. Thus, many of the root masses are hundreds of years old, have resprouted numerous times, but still produce virtually no offspring. One wonders how long they can keep it up...

Dead eastern hemlocks in Dark Hollow

Beyond the chestnut, the forests of Shenandoah are not completely safe. The stands of Eastern hemlock, so common in wet protected drainages in the east, are under assault. In this case, it isn't a fungus, but an insect. The woolly adelgid is a scale insect, introduced from Asia in 1924, that sucks the sugary phloem out of new needles of hemlock trees. While the tree can survive a few years of this, eventually they simply can not get enough nutrients to their roots and die off. All over Shenandoah, and across the east, hemlock stands stand as open skeletons of once lush, dark canyon bottoms.

Cascades within Dark Hollow

Anyways, when visiting Shenandoah, a must see place is Dark Hollow Falls. There is an excellent relatively short loop hike that will take you from the upland deciduous forests, down into the hollow (an eastern name for narrow drainage), following the creek and then loops back up to a set of nice waterfalls. This hike leaves from Byrd Visitor Center off the Skyline Drive.

Dark Hollow Falls from above

When we were at Shenandoah, it was a heatwave of 105 degrees down in DC and into the 90's and humid at 4000 feet elevation. So, to be able to descend into the cool shade of the hollow and then take a dip in one of the pools was a nice relief.

Cooling off on a hot and humid day

Early in the morning is an excellent time to drive up onto Skyline Drive to get a panoramic view of the Appalachians. Mornings tend to have the least haze, as the updrafts have not yet begun to bring water vapor, dust, and pollution to higher elevations. But, nonetheless, even at 6am the skies were hazy in July.

But, the condensation clouds and haze did make for some beautiful sunsets at our campsite at Lewis Mountain.

No comments: