“Cairns: Messengers in Stone,” by David B. Williams, October 2012, The Mountaineers Books, 192 pages, paperback, $15.95.

Acadia National Park has a rock problem.

For decades, rangers and ridge runners have spent time and sweat building and breaking apart cairns, the man-made rock piles that mark many trails throughout the park. And for whatever reason, visitors continue to tamper with these important trail markers.

“2012 was a bad year for cairns in Acadia,” said Charles Jacobi, a natural resource specialist who has worked at the park since 1984. “Not only do we have the tampering — adding a rock and subtracting a rock from a cairn — sometimes people come along and knock down a whole slew of them. It doesn’t happen very often, but it happened this summer in several places. On the South Ridge Trail of Cadillac, almost every cairn got knocked down.”

To restore the trail, Jacobi thinks he’ll need a six-person crew and three full days to walk the ridge and arrange the scattered rocks back into cairns.

For the past 15 years, he has worked with park staff and volunteers to maintain Acadia trails and educate people on Leave No Trace principles. His efforts recently caught the attention of Seattle author David B. Williams, who interviewed Jacobi for “Cairns: Messengers in Stone,” a 2012 book about the history, significance and construction of cairns throughout the world.

“Every park ranger I have talked to has said the exact same thing — that it just seems to be getting worse,” said Williams about cairn maintenance.

Just a few pages into the book, Williams writes about Jacobi’s first cairn experiment, conducted in Acadia in 2002.

With the help of park rangers, Jacobi recorded the alterations visitors made to the 67 cairns marking the exposed South Ridge Trail up Cadillac Mountain.

It was easy to notice changes because every single cairn looked the same; they were Bates cairns: two large rocks holding up a long flat rock, on top of which sits a single pointer rock. The name honors Waldron Bates, who designed this style of cairn in the early 1900s and used them to mark many of Acadia’s original trails. Over the years, conical cairns (piles of rocks most common to alpine Maine trails) replaced Bates cairns. But in 2001, Jacobi set to work to reintroduce Bates cairns to Acadia. Now they are again seen marking the most popular trails in the park.

For Jacobi’s 2002 experiment, rangers found that visitors altered roughly a third of the cairns marking the South Ridge Trail every five days. Usually visitors added rocks, but they also removed rocks, destroyed one cairn and built an additional 16 cairns.

For the second month of the experiment, Jacobi posted educational signs along the trail that stated: “Cairns are carefully places piles of rocks build by trail crews to mark trails and guide hikers. Adding to cairns or building other cairns or rock objects detracts from the natural landscape, causes soil erosion and plant loss, and misleads hikers. Do not add to or build cairns or other rock objects. Leave the mountain and rocks as you find them.”

“I think it comes back to the idea of trust,” Williams said. “I think that’s part of the wonderful aspects of cairns, that it they symbolize a community. The reason you trust them or anyone trusts them is because you trust anyone who went [on the trail] before.”

During the second month of the experiment, cairn alteration dropped significantly, from 35 percent to 20 percent. But people destroyed three more cairns than the previous month and built an additional 15 of their own. In other words, the signs didn’t solve Acadia’s rock problem.

So, why are so many people playing with rocks?

“We could argue they are one of our earliest forms of communication,” Williams said. “I mean people have been piling up rocks for thousands of years, whether to mark a trail, territorial boundary, for hunting or to mark a memorial spot.”

In fact, a cell phone application called “The Stones of Tranquility” is based on the ancient Zen practice of stone stacking. “Let the stones provide you with stability, balance and focus on the present,” the application’s description reads.

“Humans have a fascination with rocks, whether it’s collecting them or building with them, and I can understand that,” Jacobi said. “I think building cairns is a great lot of fun. I just wish that when we do it, we could be assured it would last for a few years — or even 100 years like some of the Bates cairns.”

Original 100-year-old Bates cairns can still be found marking the less-traveled and abandoned trails of Acadia. They’re recognizable by the amount of lichen growing on their surfaces, said Jacobi.

This year, Jacobi and three fellow researchers conducted a study to determine what type of educational signs are most effective in discouraging people from altering cairns on the Gorham Mountain Trail, which sees 300-500 hikers a day during the summer.

“Any sign is better than no sign, and that’s good news,” said Jacobi of their results, yet no sign appeared to be significantly more effective than the others.

Today, signs about cairns are posted on the most popular trails of Acadia, and an educational display about cairns is located at the park visitor center. Yet Jacobi still finds plenty of holes in the soil of Cadillac Mountain’s summit, evidence that people actually pry rocks out of the ground in an effort to make their mark on east coast’s tallest mountain.

It doesn’t help that many old hiking guides encourage the traditional act of adding a rock to mountain summit. So for many people, adding to summit rock piles is a part of their hiking routine.

“The cairns on top of Dorr and Sargent mountains are 20 feet wide and 8 to 10 feet high. It would fill my office,” Jacobi said. “And all those rocks came from somewhere on the mountain. All of them at one time served as habitat for plants to grow around and spiders and other invertebrates to get cover … I think most people don’t think about that, but I do.”

As Williams makes clear in his book, this problem isn’t unique to Acadia National Park. Playing with rocks is a universal tendency among people. It simply becomes problematic in areas that see a lot of foot traffic, such as national parks.

But even on top of some more remote Maine mountains, there are what Jacobi refers to as “cairn cities,” groups of cairns built up over time by hikers.

Baxter State Park also deals with visitors piling up rocks, mainly on Katahdin (which is also mentioned in “Cairns: Messengers in Stone” for the famous “Mile-High Cairn” located on the mountain’s Baxter Peak, the end of the Appalachian Trail).

“We have seen some of it, but not a lot because we have patrollers up there speaking to people about the environment,” said BSP Naturalist Jean Hoekwater. “It is a trend we are aware of, and we would have concern if it grew.

“Leaving your mark in a wilderness park shows pretty much a complete misunderstanding of why the park is there and what you might be learning from it,” Hoekwater added. “It’s very hard to deal with that kind of thing. The thing that makes New England and Maine and Katahdin different is lack of that.”

In places like the Tableland of Katahdin and the coastal mountains of Acadia, fog is often an obstacle for hikers trying to follow established trails. Cairns are more visible in fog than painted markers, and so it’s important that they be left in place.

“People are trying to find ways to interact with the outdoors and have a concrete relationship,” Hoekwater said. “A lot of them aren’t aware and aren’t experienced enough to call up a trail program and volunteer to start working on trails. But if you want to build cairns, go work with a trail group. If you want to move a rock, there are constructive ways to do it, and that [structure] will be there a long time because its a legitimate thing.”

Jacobi will certainly be looking for help this spring when he has to reconstruct the cairns throughout Acadia National Park.

Visit the Williams’ website at geologywriter.com. Several nonprofit organizations conduct trail work throughout the state, including Friends of Acadia at friendsofacadia.org, Friends of Baxter State Park at friendsofbaxter.org, the Maine Appalachian Trail Club at matc.org, and the Appalachian Mountain Club at amcmaine.org.

Aislinn Sarnacki

Aislinn Sarnacki is a Maine outdoors writer and the author of three Maine hiking guidebooks including “Family Friendly Hikes in Maine.” Find her on Twitter and Facebook @1minhikegirl. You can also...