I’m rereading a book about the outdoors published 75 years ago that still has lessons about the environment for the 21st century. It’s the classic, “A Sand County Almanac,” by Aldo Leopold, which has sold more than 2 million copies and has been translated into 14 languages.

Within the pages are descriptions of wildlife behavior, which I enjoyed when I first read the book. This time reading, however, I was even more interested in his philosophy of conservation ethics, a new and unchartered ideology during his time. Reading such books instills comparisons between conservation ethics back then and those of today.

In his chapter, “Marshland Elegy,” Leopold describes a “pandemonium of trumpets, rattles, croaks and cries that almost shakes the bog with its nearness … at last a glint of sun reveals the approach of a great echelon of birds. On motionless wing they emerge from the lifting mists, sweep a final arc of the sky and settle in clangorous descending spirals to their feeding grounds. A new day has begun on crane marsh.”

I have been lucky to experience thousands of sandhill cranes enter a huge marsh at dusk at Jasper-Pulaski Fish and Wildlife Area in Indiana.

Though Leopold described the cranes at dawn in his book, those words easily could have described the descent of these magnificent birds into their nighttime sleeping quarters.

Even in December, many remain in Indiana, not yet flying farther south until food and open water is no longer available.

Leopold, a Yale School of Forestry graduate, was a professor of game management at the University of Wisconsin in Madison. It was the first such professorship of any wildlife management program in the world.

When not teaching, Leopold went to the nearby land he owned. There he turned an old chicken coop into a small retreat along the Wisconsin River on land that was logged, farmed and eventually left abandoned.

It’s called The Shack. Leopold planted thousands of trees and restored or enhanced the original sand prairie on the property. I visited the Aldo Leopold Foundation last summer to see The Shack and the glorious sand prairies.

There I learned that Leopold died in 1948 fighting a grass fire on a neighbor’s farm. He had just been named by the United Nations as an adviser on conservation.

Leopold’s thoughtful descriptions and poetic writing are inspiring, but equally compelling are his words on conservation.

Leopold was a hunter. In fact, one of his first jobs was to hunt and kill bears and wolves who reportedly preyed on livestock in New Mexico. Leopold wrote that one day after he shot a wolf, he saw a “fierce green fire dying in her eyes.”

He stopped shooting wolves and began a journey toward a new wilderness ethic, one that shunned the idea that humans owned and dominated what thrived in the wild. In his chapter, “A Land Ethic,” Leopold writes, “It is only in recent years that we hear the more honest argument that predators are members of the community, and that no special interest has the right to exterminate them for the sake of a benefit, real or fancied to itself.”

He added, “This enlightened view is still in the talk stage.”

After reading those words, I wondered if humans today are any more enlightened about this subject than they were seven decades ago. I pondered, as best as I could without judgment, the fact that certain species are still being killed in the 21st century because they are deemed incompatible with human endeavors.

One example is the wolves that stray outside the boundaries of Yellowstone National Park, where they were introduced in 1995 after a long absence. If any of those wolves takes one step beyond Yellowstone, it can be legally hunted and trapped.

Other classic outdoor bookwriters explore wilderness philosophies as well. Sigurd F. Olson, in his many books including “Reflections from the North County,” written in 1976, wrote about his experiences canoeing in the Boundary Waters Canoe Area Wilderness in northeastern Minnesota.

He writes of searching for an ancient silence in the wilderness that, “this planet knew before the advent of modern man.” He also expounds on his belief that a conservation ethic can only help the environment if it is accompanied by a love for the land and an understanding of the inner workings of nature.

Sigurd Olsen served as a conservation consultant to the federal government before his death in 1982.

There are many more classic books written by intelligent conservationists from the past whose words seem even more cautionary today. “Silent Spring,” by Rachel Carson, comes to mind.

My goal for the new year is to read more such books, including several I haven’t yet read written by Olson and Leopold.

In the foreword to his book, Leopold wrote something that is just as meaningful to me today as it was when he wrote it years ago.

For some, he writes, “The opportunity to see geese is more important than television and the chance to find a pasque flower is a right as inalienable as free speech.” I would like to tell Leopold that I, too, have seen the rare pasque flower growing in a protected prairie in northern Illinois.

Sheryl DeVore has worked as a full-time and freelance reporter, editor and photographer for the Chicago Tribune and its subsidiaries. She’s the author of several books on nature and the environment.

sheryldevorewriter@gmail.com