Atlanta — For nearly two months he trekked dirt roads and railroad beds, sometimes hitching rides on horseback through the ''noble forests'' of Kentucky on his way southward to Florida.
Passing the mouth of a cave, he described ''an abundance of cold water and cold air that issues from its fern-clad lips.''
That was 1867. The traveler and writer was John Muir, a founder and first president of the Sierra Club. Partly because the club has promoted preservation of vast tracts of lands - including what is now Yosemite National Park, in California - Mr. Muir is usually associated with the West.
But at the age of 29, Muir thought it important to take a 1,000-mile walk through the Southeast to see and describe its nature.
Now, 117 years later, Bruce Means, an ecologist who teaches at Florida State University, has just finished traveling the same route, to observe the extent of changes along the way.
Comparing his notes with Muir's, Professor Means says the man-made alterations in the nature along the route Muir originally walked were severe.
As a result, Means is now lobbying for reforms in logging regulations in national forests, broader environmental safeguards in dam construction, and new limits to urban sprawl that would help save the remaining plant and animal life that is natural to the Southeast.
Retracing Muir's footsteps, Means found that much of the Kentucky forests Muir described has given way to intensive agriculture. In what Muir described near Glascow, Kentucky, as the ''Eden, the paradise of Oaks,'' Means found instead ''the graveyard of oaks.'' Most of the old oaks have been replaced by spindly, trashy, second-growth maples and a few relatively young oaks.
The cave Muir pictured with ''fern-clad lips'' was Horse Cave, in Kentucky. Today, however, it ''reeks of sewage,'' its underground water spoiled by human pollution seeping through limestone from the ground above, Means says.
Stopping on the banks of a mountain river in North Carolina, Muir described the sparkling, flowing water as seeming to ''sing.''
But the mountain river Muir loved, the Hiawassee, ''sings no more,'' according to Means. He passed by the same area, he noted in his journal that the river is now covered by a lake, the result of a Tennessee Valley Authority dam.
Muir hiked into Georgia, where he spent six days camping in a Savannah graveyard, awaiting money from his brother, before walking through an area in northern Florida where cabbage palms grew ''as far as the eyes could reach.''
Muir's Florida cabbage palms are gone - replaced in large part by real estate developments, Means says.
''Man has severely altered the native plant and animal communities,'' Means says. ''We have very little virgin environment left. We've sullied nature.'' And the problem is obviously not limited to the Southeast, he says.
Although there is an abundance of trees and other plants and animal species in the Southeast, Means says they're not always the same ones that existed just a century ago. Many times today's variety of animal life does not include the same mix of species or ages among the species.
Preserving nature's rich variety of species, even if only examples of it can be saved, is important, Means explains.
Plants and animals survive in systems in which each part depends on the other parts, he says. By wiping out some species with unrestricted development, society loses the opportunity to study certain species and ecosystems.
Among other things, potential products from disappearing plant and animal species are lost in the process, he says.
''We just have not finished our basic inventory and cataloging of animal and plant species in the US,'' says Means.
Gene Coan, the Sierra Club's assistant conservation director, makes a similar point. Species or ecological systems ''messed up and destroyed can never be replaced,'' Mr. Coan says. ''We don't know what use people want to make of things hundreds of years down the road. There's a lot of potential out there.''
Muir was observant, but sometimes even he overlooked impending dangers, Means suggests.
In his book, ''A Thousand Mile Walk to the Gulf,'' Muir barely comments on the loggers he passed. There is no reflection by Muir of the tremendous changes logging would bring to the natural variety of trees in the area, Means says.
Means, who is also writing a book, says he is not against use of animals and plants for human benefit, but suggests that selective use can preserve examples of natural environments.
In logging, for example, he would prefer to see greater use of selective cutting to leave some trees of a specie to reproduce and leave a variety of ages of trees for study.
Concerning dam construction, Means suggests that the cumulative effect of dams on a river be considered in relation to their possible destruction of certain animal and plant species.
Many of the dirt roads Muir once walked have become paved roads, and Means walked much of the way on pavement, that he describes as ''miserable, horrible, awful.''
Although Muir often accepted invitations for a night's lodging from people along the way, Means found fewer invitations.
Taking only a small pack for his journals and a few personal items, Means slept several nights in the woods on pine needles or leaves. About half of the nights, he slept in motels or hotels.
To follow Muir's trail, Means had to study historical records in courthouses to verify old routes. ''I think most of the time I was pretty close to his (Muir's) footsteps,'' he says.