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Maps Protect National Treasures

by Judy Purdy


Feature  |  About the Maps

Scientists trekked by foot, car and jeep to 2,000 locations within the Great Smoky Mountains National Park to gather data on plants, animals and local geography and to digitally record data for the vegetation map and associated database.

The view along the road to Clingman's Dome has changed drastically in recent years. An onslaught of introduced insects and the effects of air pollution are destroying native fir and spruce trees and decreasing the diversity of the area's plant communities.

Immature balsam wooly adelgid a threat to native firs

As an ecologist for the Great Smoky Mountains National Park, Mike Jenkins has the daunting task of tracking natural and man-made threats to the ancient, pristine wilderness that draws 10 million visitors each year.

To manage the park's complex, often fragile, plant communities, Jenkins says, "you first have to know what you have."

When what you have is half a million acres of mountains, forests, streams, hidden coves and rocky crags not to mention 100 species of trees, more than 1,570 species of flowering plants and another 4,000 non-flowering species well, you need a little help getting it all in order.

That's Roy Welch's specialty.

As director of the UGA Center for Remote Sensing and Mapping Science, Welch makes maps in ways that early cartographers could never have imagined. Depending on the project, he combines aerial or even satellite images with data collected via plain, old-fashioned boot leather to create a layered, comprehensive picture of an area: not only its geography but also its plant life and natural history.

Having already completed computer databases and detailed vegetation maps of the Everglades National Park and other protected lands in Florida (Research Reporter Summer 1995), Welch was a logical choice for the Smoky Mountains project.

But the Smokies provided entirely new challenges. For starters, the park is home to the richest, most diverse flora and fauna in eastern North America, said plant ecologist Marguerite Madden, the center's associate director for environmental studies. More than 100 kinds of common and not so common trees from pines to silverbells dot the park's landscape. Thousands of shrubs and wildflowers bloom within its borders from spectacular rhododendrons and wild azaleas to delicate lady's slipper orchids.

That diversity is precisely why the mapping is so important.

"Understanding forest species distribution is an important first step," said the park service's Jenkins. "So many other organisms are tied into the vegetation communities."

Mapping 500,000 acres of rugged, densely forested mountain terrain proved much more complicated than the Everglades' table-flat grassland. In both cases, vast amounts of information are stored in a computer database where the data can be manipulated and analyzed based on geographic location.

"It took about 200 hours for each of the 80 or so maps covering the Everglades and 700 hours for each of the 25 Smokies maps," said Welch, a Distinguished Research Professor of Geography. "To preserve the wilderness atmosphere in the Smokies we were not allowed to use helicopters or planes. The fieldwork all had to be done by car, jeep or foot."

The team assembled natural history data by inventorying the plants, animals and terrain at 2,000 ground locations inside the park. Hiking steep slopes and remote coves of snarled vegetation, they identified 100 kinds of distinctive tree communities represented in the canopy and another 70 kinds of forest "understory" shrubs. The team's photo interpreters learned to identify those 170 various vegetation communities on aerial photos and then plotted exact locations and boundaries for each occurrence.

The team also had to correct for feature distortions on aerial photos because of elevation differences between mountain peaks and low-lying valleys. They layered and aligned two sets of recent aerial photographs with U.S. Geological Survey digital photo maps that provided ground reference points and then "stitched" the layers together.

To precisely match aerial photos, USGS maps and landmarks, the researchers relied on natural features rock outcroppings, sandy places in streams and distinctively shaped treetops instead of housetops and highways, said Thomas Jordan, the center's associate director for geoinformatics.

It was an arduous assignment, both because of the enormous amount of data and because available maps and photographs varied widely in scale. For instance, the team built a database of the Smokies that combined information from:

  • 1,200 or so aerial photos of the tree canopy at a scale of 1:12,000;

  • approximately 130 aerial photos of understory vegetation at a scale of 1:40,000; and

  • 25 USGS map quadrangles at a scale of 1:24,000.

Welch's team then used the database to build three seamless maps: one each for canopy and understory vegetation and a third for forest fire risk areas based on fuels from the vegetation.

The finished maps aren't something you stuff in a glove box: If printed at a working scale of 1:15,000, each would be larger than most living rooms. But resource managers like Jenkins can print sections rich in detail and accurate to within 15 feet and tuck them into a hip pocket.

Such accuracy is paramount in charting likely locations for forest fires or where thick, tangled plant growth impedes search-and-rescue crews, Madden said.

"Among other things, the park service will use our data to develop fire models and help fight damage caused by exotic insect pests such as the hemlock wooly adelgid. It's a type of aphid that is new to the park and it can kill a 300-year-old hemlock in just a few years," she said.

Akin to a computer-based management tool, the new map enables park staff to track the health of plant communities, including threatened Fraser firs and hemlocks, and receive feedback on protection and restoration practices.

"It provides a way to review the impact of resource management decisions," Jenkins said.

Welch's team is now turning to other projects. They have agreed to map a dozen more national park sites, including Mammoth Cave, the Blue Ridge Parkway, and Revolutionary and Civil War battlefields.

And the U.S. Department of Defense recently came calling.

"They are interested in coastal areas because of potential war activity," Welch said. "If Marines had to go ashore, where would be a good location, what kinds of obstacles would they face and how would they get around them? These are areas where mapping from air photos and satellite images can play an extremely important role."

For more information, access or email Roy Welch at

Judy Bolyard Purdy is the University of Georgia's director of research communications.


Feature  |  About the Maps


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