Only the most farsighted and intuitive of those who labored for the creation of the Smokies could have foreseen the slate of environmental challenges that would be facing the park mere decades after President Franklin Roosevelt stood astride the North Carolina-Tennessee border at Newfound Gap in 1940 and officially dedicated the Great Smoky Mountains National Park.

Roosevelt could see over the heads of onlookers to vistas 80 miles away. But today — on a good day, primarily in winter — you might get a vista of 25 miles. The brown haze that plagues Atlanta, Knoxville, Asheville and other urban centers is trapped against the mountains and bathes the park in pollution while reducing visibility.

Invasive, exotic species of plants and animals have crept into the park and are wreaking havoc on natural ecosystems. The popularity of the Smokies — the most visited park in the country with more than 9 million visitors each year — brings its own set of environmental challenges. Meanwhile the specter of anthropogenic global warming hangs over the park like a black fog.

Ecosystem assault

“The issue of invasive species is number one in my book,” said Greg Kidd, senior program manager of the National Parks Conservation Association’s Blue Ridge Field Office. “What makes the Smokies so incredible is the opportunity to keep this unique set of ecosystems intact. But the fact is we have so many exotic, invasive species in the park now, hammering at the natural ecosystems, particularly the diversity of tree species, that it’s not too hard to envision a Great Smoky Mountains National Park devoid of much of its ecosystem diversity.”

Indeed, the biodiversity of the Smokies, with its amazing array of ecosystems, is what makes the park so unique. The Smokies has some of the most diverse plant life on the planet — more than 130 tree species alone. Arthur Stupka, who served as the park’s first naturalist from 1935 to 1965, put the Smokies lush forests in perspective this way: “Vegetation is to the Great Smoky Mountains National Park what granite domes are to Yosemite, geysers are to Yellowstone and sculptured pinnacles are to Bryce Canyon National Park.”

But 75 years, later, that diversity is being threatened.

The balsam woolly adelgid has decimated most of the high-elevation Fraser Firs and the hemlock woolly adelgid is quickly dispatching hemlocks across the park. Butternut canker, dogwood anthracnose and beech bark disease are changing the composition of the park’s mighty forests.

Meanwhile, invasive plants pose a serious and silent threat of their own. As they edge out native flora, the natural balance between the park’s plants and animals that evolved in tandem over the eons is being thrown off-kilter. On a micro-level, even soil chemistry is disrupted by a takeover of an exotic plant species.

Supervisory Forester Kris Johnson and her staff have engaged in hand-to-hand combat with alien species like multiflora rose, garlic mustard, honeysuckle, princess tree and a multitude of others. The Smokies actively targets 50 species of invasives. Tactics include labor intensive digging and pulling by hand, as well as the use of chemicals.

“We’ve been working on invasives for decades and we are seeing the benefits in many of our target areas,” Johnson said. “But we’ll never reach any kind of equilibrium. There is just too much constant pressure from outside the park.”

Rooting out exotics from an area the size of the Smokies is daunting, but with the sanctity of the largest intact ecosystem in the Southern Appalachians on the line, it’s a battle worth fighting, said Bob Gale, a biologist with the WNC Alliance, an environmental group working with the park to combat exotic plants. When Gale escorted a volunteer corp to pull a privet infestation in the Deep Creek area, the sight was depressing at first.

“It was so bad it was literally the entire understory of the forest,” Gale said. “We lost all the plant diversity on the forest floor.” Just a year after their work, native plants are springing back from the forest floor, Gale said, calling it a “miracle.”

Air pollution woes

On hot summer days, visitors seeking the respite of cool mountain air in the Smokies might be shocked to see a sign in the park visitor center warning of dangerous ozone levels. Rangers even have to cancel guided hikes, as physical exertion under high ozone conditions is ill-advised.

Air quality monitors show the Smokies has some of the most polluted air in the nation, stemming mostly from dirty coal-fired power plants hundreds of miles away, and to a lesser extent auto emissions from distant urban areas. The Smokies’ high ridges are particularly susceptible to wafting pollution. Researchers over the past decade have shown a direct correlation between ozone levels and leaf die-back on certain plant species.

But the average tourist doesn’t need an air monitor to tell them there’s pollution in the air.

“It’s easy to see that visibility is not as good as it was,” said Jim Renfro, air quality specialist in the park since 1986. The park is even in violation of federal air quality standards.

The political will to make coal plants clean up their act has been slow at best, Kidd said. So environmental groups have turned to the legal arena over the past decade and successfully forced progress on the issue. The state of North Carolina even got in on the act by suing the Tennessee Valley Authority, a major source of dirty coal pollution for the region, and won its case this year. Impacts of TVA’s pollution on the Smokies figured prominently in North Carolina’s legal argument, including a claim that tourists will stop coming if the famed mountain vistas are obscured by smog.

Global warming in the Smokies

Air pollution also takes the form of acid rain, which is five to 10 times more acidic than normal. As a result, some high elevation streams have an acid content comparable to 200 railroad cars of sulfuric acid being spilled in the park each year, according to researchers. A loss of brook trout in particular is blamed primarily on acidification of streams, which alters the ions in their blood, according to park researchers.

Soil in the park has grown more acidic since regular monitoring began in the mid-1980s, which could eventually prove harmful to some plant species. The high peaks of the Smokies, often shrouded in clouds, even have the unusual problem of acid fog.

Another side effect of air pollution is mercury fallout, which also comes from coal-fired power plants. Mercury levels in Lake Fontana, flanking the park’s southern end, led the state of North Carolina to issue a consumption advisory for wall-eye from the lake last year.

Over the past 10 years, monitoring shows air quality in the park is improving or at least remaining stable.

“We’re mandated to preserve our resources unimpaired for future generations so we keep doing what we can do — monitoring, research, educating and sharing our information with regulatory agencies,” said Renfro, a self-avowed optimist. “It’s not going to happen in the next 10 years but we’re making advances. And the fixes are there. The technology exists.”

Another side effect of air pollution is global warming. It poses a serious threat to the park’s ecosystems. Plants and animals have adapted to niche microclimates on the flanks of the mountains, each claiming its own corner in the spectrum of elevations. If the temperature gradient shifts, the niches could be bumping into each other or simply disappear.

The Smokies has been highly engaged in climate research in recent years, both in-house and from outside researchers who see the range of elevations in the park as fertile ground for tracking temperature changes. Global warming is now leading the research permits sought in the park.

A leading climate researcher in the park, Syracuse professor Jason Fridley, peppered the park with 170 temperature-loggers about the size of a nickel called “eye-buttons.” While some theories assumed the species adapted to the highest, coldest peaks could get pushed off the top of the mountain if temperatures warm, Fridley found that the peaks could hold their own thanks to the cooling effect of moisture while the ecosystems in the mid-range elevations get compressed.

Loved to death

The Great Smoky Mountains National Park is the most visited in the country. It’s a badge worn with honor, but comes with its own share of challenges. Take the 1.5 million visitors that swarm Cades Cove every year, and just that small slice of the Smokies would still rank in the top 10 most visited parks.

“An overcrowding of vehicles in certain parts of the park puts a terrible strain on the resources,” Kidd said. “People pull off and park anywhere they can. They get stuck in traffic jams with idling engines spewing exhaust. People who planned on a pleasant trip in the park find themselves in a four-hour traffic jam.”

North Carolina is oft-called the quieter side of the Smokies without the hoards or hustle and bustle found around Gatlinburg.

“For whatever complex of reasons, once you get more than three or so miles from a trail head, you very quickly find yourself without a whole lot of people around,” Kidd said. “You can very quickly find solitude in the Smokies.”

But the human impacts are nonetheless an issue to grapple with. The Smokies’ popularity strikes at the conundrum faced by any national park. The best way to protect it would be placing it in a lock-box, off-limits to humans. But the mission of the park service calls for providing for the park’s enjoyment today while at the same time protecting it “unimpaired” for future generations.

“When you think about the problems facing the park, it’s actually quite remarkable what a good job the Smokies has done through the years to accommodate all the visitors as well as they do,” Kidd said. “It’s a huge task to provide a high-level wilderness experience while policing the resources at the same time.”