An hour after Corbin applies the customized (and environmentally safe) mixture of orange dye, gypsum and organic filler, the dye seeps deep into the ginseng root, permanently marking the tissue with blazes of orange. In addition, the powder contains color-coded silicon granules, each no larger than a coarse flour grain. When viewed under a microscope, those granules will tell law enforcement officials when the root was marked and where it was collected. Such a marking program works on two levels, Corbin explains. "Legitimate ginseng dealers won't accept dyed roots, because they know they were illegally harvested from the national park," he says. "And the silicon granules enable us to identify the plants in court."

Anyone can legally harvest ginseng from their private property and, with a permit, from most national forest lands. National parks, however, are off-limits to plant collectors, and park managers are worried that as ginseng populations are being increasingly whittled down on private lands, collectors are turning to public lands.

Ginseng poachers in particular prize the protected and secluded hollows of national parks, and have targeted the Little River Canyon National Preserve in Alabama, Mammoth Cave National Park in Kentucky, Shenandoah National Park and the Blue Ridge Parkway in Virginia, in addition to the Great Smokies.

Increasingly, the plants they seek are being protected by countermeasures worthy of Cold War espionage. Along the Blue Ridge Parkway in North Carolina and Virginia, hidden electronics monitor stands of pitcher plants. In western deserts, tiny metal tags are implanted in prized cacti to identify recovered plants. Microtaggant, a powdered marker developed for the explosives industry, is being used on the Blue Ridge Parkway for marking galax. In Arizona, Corbin's dye marker is used to combat the theft of petrified wood. And across the country, seismic detectors placed on trailheads alert rangers to the footsteps of potential poachers.

For law enforcement officials who have long relied on traditional-and time-consuming-surveillance techniques, the new technologies are a revelation. "The dye and silicon markers are as good as having a bar code on the plant," says John Garrison, a law enforcement specialist for the Blue Ridge Parkway. "Now we can say, 'These plants are the property of the U.S. Government, no ifs, ands or buts.'"