|Copyright: Bob Harrison (BobH)
|Date Taken: 2004-08-08|
|Camera: Olympus 700C UZ|
|Exposure: f/3.2, 1/8 seconds|
|Details: Tripod: Yes|
|Photo Version: Original Version, Workshop|
|Date Submitted: 2007-12-02 2:28|
|[Note Guidelines] Photographer's Note|
|This image is somewhat related to my recently posted lichen picture.|
Maine is a rocky place, with thin soil and lots of exposed bedrock. But that doesn't stop life from digging in its fingernails and hanging on tenaciously. It is common to see small trees in Maine growing with no soil visible and roots disappearing into cracks in the rock. But it is less common to see trees this large in that situation. These trees are pioneers in the same way as lichens, but on a much bigger scale. They have a much deeper grip on the surface and correspondingly larger impact on the deterioration of that surface.
This image was shot in Maine's Acadia National Park, looking across a 4 m deep gulch cut into the granite by a small stream. The gulch is about halfway up the side of a 400 m high mountain which is little more than a large knoll of Acadia's famous pink granite. Around the base of the mountain, the accumulated soil is substantial enough to support white pine trees sometimes exceeding a half meter in diameter and 40 m tall. The mountain top is the ecological opposite- several hectares of glacially smoothed granite and occasional lichens. Scattered small pockets of windswept sandy soil support a few highly stunted trees, sometimes only tens of cm high, and often with branches growing only on the downwind side. The trees in this image represent the transition between those two extremes.
The photo shows cracks in the rock which run parallel to the slope and are part of the exfoliation process that occurs throughout the park's exposed granite. These cracks are both good and bad for the trees that send roots into them. Without the bits of soil accumulated in those many deep cracks, this slope would not be forested as it is. But in some places large granite flakes become dislodged and slide down, damaging the fledgling forest. The term flake may be misleading. While many rock flakes are small, some are multi-ton slabs that can be 1 m thick and 10 m across. When these larger flakes slide, mature trees may still be attached, and many other trees may be mowed down in the process. The forest is scarred until new pioneer trees take hold in the newly exposed cracks and grow to maturity. This situation is ecologically similar to when lichens reclaim their previously colonized territory after the overgrown colony sloughs off.
Direct evidence of the exfoliation process is widely visible and scars large and small scattered around the park attest to the impact of this mechanism of "erosion". Growing tree roots and the freeze-thaw process are powerful partners in slowly prying open the slightest cracks in the otherwise nearly impervious granite. Winter cold and ice contribute greatly to this gradual destruction, providing molecular level wedging deep in the cracks to break the rock loose, then lubricating the downward slide. Winter temperatures on the Maine coast commonly range far on both sides of freezing, providing many cycles of freezing and thawing each year.
The biological succession that these trees represent is a positive feedback loop. Each assault on the integrity of the rock provides a little bit more room for the success of the next assault. The forest in this image is the product of several millenia since the last ice age, when glaciers scraped the rock bare. In several more centuries this slope will likely be covered with soil made up of the current trees and their years worth of leaf detritus, digested by microbes, fungi, and various small soil animals. By that time global warming plus the rich soil could even allow the growth of a dense hardwood forest quite different than the sparse evergreens that now dominate.
This image had modest shadow lightening and contrast applied, but was otherwise unmodified.
gondox, Heaven has marked this note useful
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I love this pov and the many patterns on your photo, and your notes are also very interesting!
On the left side tree you can see a noticeable amount of color aberration. It usually appears in a place like this where dark contours meet bright sky. I made a workshop to show how it can be removed, please let me know if you liked it or not!
Have a nice day,
- [2007-12-02 4:48]
I like the subject and the composition very much.
Unfortunately, your picture lacks of well balanced lighting. The bright tones are burnt, with the total loss of details. There's also a problem with the colors: I find some strange magenta parts, especially in the trees, and parts of the roots have a red-magenta cast.