Showing posts with label geology. Show all posts
Showing posts with label geology. Show all posts

Monday, February 4, 2013

Misery and Joy on Groundhog Day

Classic view of Valley Forge - reconstructed soldiers' cabins and open fields
Kali's putting on pounds - she's the first to admit it - in part because she's very sedentary at work.  So, when I proposed a hike on Groundhog Day, she was up for the challenge despite overcast skies and temperatures hovering around 30 degrees.  I looked through my regional hiking guide and suggested that we walk at Valley Forge National Historical Park, a 40-minute drive from home.  We walk at Valley Forge fairly frequently, but we were afraid that our usual walk along the banks of the Schuylkill River might be muddy.  So, instead, I found a 5-mile loop hike that traversed two wooded hills in the western end of the large park,  I assumed that the elevated trails would be drier than the riparian path.  (I was right.)

The paired hills are named Mt. Misery and Mt. Joy.  They are separated by a sizable stream called Valley Creek that provided power for colonial mills.  Valley Forge had already become an important industrial community at the time of the American Revolution.  (Today, it's a sleepy suburban crossroads.)

Kali lunching on an energy bar along the Mt. Joy Trail
We first ascended Mt. Misery.  At the foot of the hill were ruins of a colonial mill with a small spring-fed stream flowing right through the building.  There were no interpretive signs indicating the type of milling conducted here, though milling operations changed frequently in response to local needs, so the mill easily could have processed a dozen different products during its useful life.

Ruins of a colonial mill at the foot of Mt. Misery
We continued our ascent through open woodlands with an understory of mountain laurel (Kalmia latifolia), Pennsylvania's state flower.  The woods support mostly drought-tolerant chestnut oaks (Quercus montana), with smaller numbers of black oaks (Q. velutina) and Northern red oaks (Q. rubra).

Mossy log in the leaf litter
The Appalachian Piedmont is a geologist's dream (or nightmare).  The Piedmont features rocks that have been repeatedly tortured by the tectonic collisions of North America and Africa over the aeons.  As such, metamorphic, igneous, and sedimentary outcrops often occur in close proximity.  Mt. Misery, Mt. Joy, and Valley Creek are good examples.  Mt. Misery and Mt. Joy are composed of quartzite, a metamorphic rock derived from melted and compressed sandstone.  The erosion resistant quartzite hills stand several hundred feet above the surrounding landscape of sedimentary rock.

A quartzite boulder in the woods
A whimsical cairn along the trail
Like nearly all national parks, hunting is prohibited in Valley Forge.  As a result, the population of white-tailed deer has exploded.  Vehicular collisions are common on the roads through the park, the forest understory is completely decimated, and the deer have created a browse line on the vegetation as high as they can reach.  No young trees whatsoever are present to replace the mature canopy trees.  Fortunately, after a decade of documenting the damage, the National Park Service allowed U.S. Department of Agriculture sharpshooters to begin to cull the deer last year.  It's too soon to determine how effective the population reduction will be, but it couldn't get much worse.  Throughout the park's woodlands are dozens of fenced exclosures that were used to demonstrate the effect of deer browsing on the forest understory.

The depauperate woods at Valley Forge, here along the Mt. Misery Trail
After Kali and I descended the far side of Mt. Misery, we walked across meadows of native grasses and down to the banks of Valley Creek.  Valley Creek flows through a limestone valley fed by numerous springs.  As a result, it is the only steam with water consistently cold enough for trout in southeastern Pennsylvania.  There were probably native brook trout in the creek at one time, but fishers have stocked aggressive European brown trout in the stream for angling.  Regardless of the species in the stream, though, none of the trout can be kept - serious PCB pollution in the upper watershed from railroad yards has contaminated the creek, so all fishing is catch-and-release.

Kali on a footbridge spanning Valley Creek
We then ascended Mt. Joy and followed the trail high above the deep, steep valley separating the two hills, ending our walk where we started near the mouth of Valley Creek.  We both enjoyed the hike very much for its invigorating climbs and its novelty.

View westward from Mt. Joy across the Valley Creek gorge to Mt. Misery