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Tuesday, August 17, 2010

Rephotography


Keeping a visual record of changes within a landscape



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The interest in global warming has been the biggest factor to popularize the genre of rephotography. Glacier documentation is at the center of the use of rephotography to show the effects of climate change. The USGS is involved in several rephotography projects focusing on diminishing and retreating glaciers in North America. Their best-known project started in 1997 looking at retreating glaciers in Glacier National Park in Montana. The repeat-photography project photographed 60 glaciers in the park. The study showed that only 26 named glaciers still exist of the 150 glaciers present in 1850. USGS scientists have estimated that at the current rate of retreat, by 2030, there will be no glaciers left in the park. The USGS website states, “While less quantitative than other high-tech methods of recording glacial mass, depth, and rate of retreat, repeat photography has become a valuable tool for communicating effects of global warming.”

Perhaps the most ambitious and creative repeat-photography project currently underway is James Balog’s Extreme Ice Survey (EIS). The 27 EIS cameras presently are positioned above glaciers in 15 locations around the world, including Greenland, Iceland, Alaska and Bolivia. The cameras are fixed in protective housings and situated to give them a broad view of the glacier terminus. The cameras are programmed to make a photo many times a day, season after season. The results are combined to produce a video clip that shows seasonal growth and retreat of the glaciers. Balog hopes to keep cameras in position for several years in order to show the retreat of the glaciers beyond the seasonal fluctuations, which is a result of global weather changes. Already his EIS project has produced remarkable images of glacier retreat.

In the coming weeks, I’m traveling to another repeat-photography assignment: returning to southeast Australia and the Hume Plateau. In 2002, I photographed a team of scientists, including Roman Dial and Stephen Sillett, as they explored and recorded data within the top canopy of 300-foot-high mountain ash trees, a type of eucalyptus. The team climbed these eucalyptus trees with ropes and a form of travel from one tree to another called “canopy trekking.” The scientific component of this adventure was to establish that the trees in Wallaby Creek were the tallest stand of hardwood, flowering trees in the world. The tallest of these trees, called Big Ash One, was 91.6 meters tall (over 300 feet) and estimated to be close to 400 years old. The discovery and measurement of Big Ash One also confirmed, for the first time, a living tree over 300 feet tall on mainland Australia.

The photograph here was taken during a survey of this spectacular stand of trees. I shot this photo of the Wallaby Creek forest as scientists ascended a study tree. I shot from a fixed rope in Big Ash One from a position about 200 feet above the forest floor. For this vertical panoramic, I used a Hasselblad XPan film camera with a 40mm lens and Fuji 100 film. In February 2009, this forest was destroyed in the worst bush fire in Australia’s history, Black Saturday. It’s now a forest of standing dead with only an estimated 60 trees having survived the fire.

My plan is to return to this area and, with original GPS coordinates, use ropes to rephotograph what remains of the giant trees. I’ll attempt to photograph in the same locations I did when Wallaby Creek was discovered to be home to some of the tallest trees in the world. How exciting it will be to return, see the changes and to document them. Fire is an integral part of the regeneration of eucalyptus forests. Recent reports from the field have informed me that the forest is regenerating, and the new growth of mountain ash trees in Wallaby Creek is about six to 10 feet tall. Park rangers estimate that in the next five years, the trees may be over 60 feet. I look forward to shooting that for another rephotography project.

Bill Hatcher is a regular contributor to National Geographic and Outside. Visit www.billhatcher.com.

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