As the lower stretch of the trail winds through a grove of saguaros, Bertelsen tells me their stories. These cacti stand in the front rank of the Coronado National Forest's Pusch Ridge Wilderness, and the flashlight tour is like night rounds through a military field hospital. He spotlights bullet holes, severed arms, and slashed flesh.
"I caught the guy doing this," he says, pointing to the scabbed-over hack marks left by a machete. "He said he wanted to hear what a saguaro sounded like when it fell. I was not kind to him."
A crescent moon will not rise for several hours, but the cliffs of the lower canyon's western wall glow in the light from the city below. Bertelsen points his flashlight toward an overhang a few hundred feet up and remembers the colony of swifts that once lived there. "But two climbers went and hung right below it for a whole day," he says. "That was the last I saw of the swifts."
Then there were the Boy Scouts who cleaned the spring box and wiped out the unusual patch of low-elevation bluebells; the well-intentioned man who chopped down much of the canyon's desert cotton, mistaking it for poison ivy; and the roaming dogs that Bertelsen believes have caused the sharp decline in the population of bighorn sheep, the inspiration for setting the land aside as wilderness in 1978.
It begins to seem as if Bertelsen's dedication to this place has yielded little but frustration and grief.
Yet Bertelsen says his visits confirm his belief in the value of this area, so close to Tucson. He shines his flashlight across the hillside, picking out clumps of grass. "There are about 35 species of grass right on this slope," he says, and the Latin names come rolling off his tongue. "Heteropogon contortus," he recites, with relish. "Schizachyrium cirratum."
His ability to identify grasses at 2 a.m. on a moonless night notwithstanding, Bertelsen is not a professional botanist. A former college administrator, the tall, shy, 57-year-old moved to Arizona from Ohio some 20 years ago, finally making good on the plan he formed as a 10-year-old looking through his grandmother's copies of Arizona Highways. He now earns his living as a probation officer for Pima County.
His interest in plants started with photography. "I wanted to know what I was taking pictures of," he says. At the time, there were few comprehensive floras for amateurs, so he began to keep a journal of the plants he saw, making up his own descriptive names, "yellow flower with thin leaves," for example. Somebody suggested that he take a few specimens to the University of Arizona Herbarium, and the staff there encouraged him, especially after he found a rare variety of morning glory.
Since then, he has identified some 565 plant species along this trail, which climbs from thornscrub at 3,000 feet to the pine woodland around the 7,158-foot summit. Each year he has added at least a couple of new species, and he thinks he may eventually find as many as 600, a surprising diversity for a relatively small area.
Bertelsen refers to himself as a "field botanist," and he seems well suited to the work. Philip Jenkins, the assistant curator at the herbarium, has worked with Bertelsen over the years. He praises Bertelsen's "well-developed search image," botanist lingo for the ability to identify a plant at a glance. "He has that kind of eye," says Jenkins. "It's remarkable."
This talent, along with his skill as a photographer and a willingness to comb rough terrain, have led him to contribute to a forthcoming book documenting Arizona's rarest plants, as well as other publications and surveys of the state's vegetation.
Bertelsen's attention to this canyon is minute: Over the last 17 years he has kept a weekly record of when species bloom, where he finds them, and how they disappear, reappear or migrate.
"The true value of his study in Finger Rock," says Jenkins, "is that it covers such a long time and is so chock-full of data. Long-term studies like that are what we're really missing, and it will be very informative when he puts it all together."
But the same patience which has allowed him to compile this information also makes it unlikely that he will publish it any time soon. "I'm doing it for me," he says, "not the world." He suggests that he may publish the data once he has 20 years' worth.
As he climbs the trail inspecting the ledges, gullies, outcrops and overhangs with his flashlight, he constantly picks out individual plants like old friends and remarks on how they have changed since he began coming here. When he points to a sheltered spot and tells how a camper's fire wiped out two rare plants, I think of the time, as a child, when my wayward football crushed a neighbor's plot of prized, hybrid irises. Bertelsen cautions me not to "piss on the trail so you don't kill any plants." Suddenly, the word "wilderness" seems far too crude for these fragile micro-habitats.
On Saturdays, Bertelsen is on hand as a Forest Service volunteer, watching for dogs at the trailhead, answering questions and urging visitors to treat the land gently. He shows me how he has fiddled with the trail over the years to lead people away from sensitive plants, decrease erosion and stem the mysterious urge of hikers to broaden its width. Tonight he finds that somebody has erected cairn after cairn along the well-defined path. He shakes his head and scatters the stones.
It's just before first light as we arrive at the summit of Mount Kimball. Despite the ibuprofen pills - "Vitamin I," as he calls them - the tendons in his heels are aching, he allows. Such minor problems will not stop him from making his weekly trek. "I'll be propping myself up with a couple of canes before that," he says.
As we take in the sweeping view, he mentions how some have called him the "Kimball King" in honor of his many trips up here. "But I say, no, don't. If you want to call me something, call me 'steward.' A steward protects."