Caring for Cairns at Acadia National Park

Cairns need care. For the trail user, the message is clear: "Preserve the mountain landscape. Please do not add to or build cairns or other rock objects. Leave the mountain and the rocks as you find them."

by National Park Service

Rock cairns have long been the standard trail markers to guide hikers in areas where there are no trees. Early trail enthusiasts built cairns to mark trails on most of the exposed granite summits and ridges of Acadia National Park more than 100 years ago. Today these trails offer outstanding views to thousands of hikers of the surrounding mountains and the spruce-clad islands of the Maine archipelago.

If you hike Acadia’s mountain trails you’ll see them. Piles of rock, marching up the mountain with you. Why are they there? How were they built? Is there more than one type? Who maintains them? The short story is that they mark the trail. Maybe you know that. Maybe you don’t. Maybe you don’t care about cairns. But you should. As cairns go, so goes the mountain landscape.

Now… here’s the rest of the story.

Cairns have likely marked human travel routes from time immemorial. The word cairn is Scottish, and simply means a pile of rocks. For today’s trail maintainers, that definition is a major injustice. Cairns are carefully constructed stone trail markers used in treeless areas. Crews build traditional conical cairns on the same principles as a stone wall— each rock should overlap others, have three points of contact, and slope inward. The base and height of the cairns should be about equal. It takes a long time to build a stable, proper cairn, and lots of material must be available to choose from. All material is selected from loose rock on the ground. No rocks are removed from mountain soil.

As trail markers, cairns keep hikers on a single route, protecting fragile subalpine soil and vegetation. In foggy or stormy weather, they can be lifesavers, helping to keep you safely on the trail. Each of these is a critical function of cairns, protecting the mountain landscape and you.

photo credit: Mike Bullington
A cairn near Mt. Jefferson, on the Pacific Crest Trail

A cairn near Mt. Jefferson, on the Pacific Crest Trail

Not all cairns are built in the style of a cone. In the early 1900s, Acadia trail builder Waldron Bates introduced what we now call the Bates cairn (at left0. The Bates cairn consists of two large base stones supporting a mantel between them. A fourth rock, known as the pointer rock, rested on top, and along with the base stones, pointed in the direction of the trail. Sometimes two layers of base rocks were used to gain height for added visibility.

For reasons unknown, traditional conical cairns (found all over New England’s high elevation trails) replaced many Bates cairns in Acadia, probably in the 1950s and 1960s. Bates cairns are now making a comeback along park trails. Here’s why.

First, the hiking trails at Acadia are important cultural resources, and the Bates cairn was once a defining feature contributing to the character of many trails, just like stone steps, retaining walls, and carefully designed routes. We want to preserve and maintain the trails as cultural resources. And second, although it also takes time to find the right large rocks to construct a stable Bates cairn, they are easier to build and maintain than traditional conical cairns.

This easier construction is important because Acadia hikers seem to have a never-ending tendency to tamper with cairns. Rocks are added or removed at will. Carefully built cairns mysteriously collapse. More cairns and rock graffiti in various forms appear from nowhere. Over a six week period on one trail, an average of about 1/3 of the cairns were altered every five days. Much time, money, and energy is expended to undo all of this.

All of this tampering takes a toll on the mountain landscape. Visitors often remove rocks that are still embedded in the soil, opening the door for more soil loss. Topsoil may take hundreds of years to rebuild.

Extra cairns lead hikers astray, contributing to loss of vegetation and eventually further soil erosion. They also cause hikers to become lost, creating a potential safety problem or at least a bit more adventure and frustration than expected.

Rock graffiti and many visitor-built cairns degrade the natural mountain landscape we come to experience. Who wants to see mandalas on Sargent Mountain, or see that T.S. loves M.E.?

Caring for cairns is caring for the mountain and for trail history, and it’s every hiker’s job. Pay attention when hiking. Look up to follow the cairns and blazes, and follow them closely, staying on rock ledge whenever possible.

Do not add to or build cairns or other rock objects. Leave the mountain and the rocks as you find them. Let cairns age gracefully and add to the cultural landscape of the hiking trail system. Stewardship begins when you care.

The summit of Cadillac Mountain is the highest point along the eastern coastline of North America, and among the most-visited spots in Acadia National Park. Cairns are one of the resource concerns at Cadillac. Park managers have continually had to deal with cairns at Cadillac being altered by visitors. Specifically, some cairns would be destroyed, others would have rocks added to them, and visitors would inappropriately construct others. Some of the findings the 2000 study reported are:

  • Young children (pre-adolescents) are the predominant group responsible for building and destroying cairns.
  • Family members support children who engage in cairn building. Cairn building occurs in a positive family context.
  • Children are NOT the only group observed adding stones to cairns; adults also add stones to cairns.
  • The effects of visitors building and/or destroying cairns leads to some other visitors being confused and/or having trail experiences diminished.
  • Understanding the role cairns play decreases the likelihood of cairn modification (adding stones was the activity that data from this study identified, though it is plausible that understanding also influences the likelihood of cairn building and destroying as well).
  • Cairns are intrinsically attractive in that they have an allure to those who are seeing them for the first time (irrespective of who built them).
  • By building cairns atop Cadillac and not explaining their purpose on-site, park managers actually instigate additional cairn building by visitors.

About the Author

The National Park Service (NPS) was created in 1916 and today manages over 390 units found in all 50 states and some of the U.S. territories. NPS supports and operates trails in three interlocking arenas: trails in parks, technical assistance to States and communities, and administration of much of the National Trails System.

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