It was 1980. I was headed to Punta Cirio on a class field trip, looking for boojums. These odd, ancient, upside-down carrot-shaped freaks of the plant world are all over central Baja, but in Sonora, they're found only on a rocky headland near Puerto Libertad. I made it through the sand that day. We camped later that night in a boojum forest on the coast, a ghostly full moon rising overhead.
Another photo from that trip shows Dr. Paul Martin, ringleader of this adventure and professor of the class I was taking, standing on the beach surrounded by pock-marked boojums, cardon cacti, elephant trees, limberbushes and other strange Sonoran Desert greenery. Hummingbirds flitted around our heads, sucking nectar from bright red flowers of chuparosa. One bird mistook my red shirt for a gargantuan flower.
The class was loosely called "environmental education" and met one evening a week in the old Carnegie Desert Lab on Tumamoc Hill. Professor Martin would hand around fossilized sloth turds, dead stuffed pack rats, pressed plants and often a handsome blue-bound book called The Changing Mile, by Rod Hastings and Ray Turner. The book was mesmerizing. In it were matched pairs of black-and-white photos from Southern Arizona and northern Sonora, Mexico. It was the result of a rephotography project cooked up by Hastings (an atmospheric sciences professor at the UA) in 1958 that compared landscape photos taken in the late 1800s with newer repeat photos of the same locations. The idea was to look at changes over time in vegetation across this part of the Southwest. Plant ecologist Ray Turner from the U.S. Geological Survey joined the project in 1959, and The Changing Mile was published by the University of Arizona Press in 1965.
The book has stayed next to my bed for more than 20 years. The photo I took of Paul Martin all those years ago at Punta Cirio was shot from one of the photopoints in the book. I've spent hours of my life, my eyes feeding on the images, working over the text and teaching myself how to see.
Now, almost 40 years after the original edition was born, the University of Arizona Press has published The Changing Mile Revisited. The original authors are joined by two other respected scientists with the U.S. Geological Survey--research hydrologist Robert Webb and botanist Janice Bowers.
Hastings passed away in 1974, but his spirit runs deeply through this new book. In the preface, the other three authors give him majority credit for "conceiving the book's grasp and defining its major thrust."
The "changing mile" of the title describes the elevations of the camera stations whose locations range from sea level to a mile above sea level. A new round of photography resulted in the 98 triplicate sets of black-and-white photos reproduced in the book, documenting roughly a century's worth of change in the Sonoran Desert. An additional 200 sets were used for preparing a discussion of the project's results and analysis. Three early chapters tell everything there is to know about the cultural and natural history of the Sonoran Desert.
Good science, done right, becomes a sort of high art. In the hands of those who truly love the thing they study, dry scientific writing morphs into a kind of poetry. This new book is that rare thing: a revision that towers over the original. And the original was itself a classic. The new book sings with stories and questions about a special place, and is completely accessible to anyone who cares about where we live. The photos alone pull the observer deeply into them, revealing their message.
Part of that message is that environmental change is not solely human-caused. It is also an inherent part of so-called "natural" systems as these photos so dramatically show. While human impacts are frequently severe, nature is not just some static museum piece. In these photos, we see both plant and human communities ebb and flow in the span of just 100 years. Change happens.
This is simply the best and most important book ever published about the Sonoran Desert. Period. It will change how you see the world.
