The rock stacking debate rolls on: Should walkers be encouraged to dismantle stone piles in the wild? Photo / Getty Images; Styf22

OPINION: A debate that has been dividing the outdoor community since the early Palaeolithic Age has just stepped up a gear as outdoor groups encourage walkers to “kick over cairns”. So when should you knock over stone stacks in the wild?

A National Park has vowed to “leave no stone unturned” in its battle against cairn piles.

The Yosemite National Park in California is advising tourists to knock over any rock stacks they find in the wilds of the 3000sq km reserve.

Last month the park issued a statement that it was working to remove the monuments left by visitors that were piling up in popular nature spots, as the objects were distracting and potentially a danger to endemic wildlife.

In an attention-grabbing video, the park published a clip of a ranger knocking over a giant manmade marker. Take that, eco-enemies!

The clip, which attracted 10 million views, was hardly a “Chuck-Norris-roundhouse-kick-of-righteousness”. It had more of a youth-sheepishly-enacting-wanton-destruction-because-their-mates-were-recording-them vibe.

Still, the statement issued with the clip was far more resolute.

“According to Leave No Trace ethics when we recreate in wilderness spaces, our goal is to leave no signs of our impact on the land and respect other creatures living in it,” wrote the park.

“Unfortunately, this dramatically oversized cairn is a mark of human impact and is distracting in a wilderness setting.”

But not everybody is keen to see the piles toppled.

It’s a debate that has rocked the conservation world since the stone age: to stack or not to stack?

Known as stone cairns, fairy stacks or “geological graffiti”, across the world these rock piles have become a totemic issue for outdoor enthusiasts.

Some areas have been blighted by the phenomenon, particularly in popular outdoor tourist destinations. From Lake Tekapo to the Outer Hebrides, the opinion has turned against the practice of leaving stones to mark trails.

It’s a practice older than recorded human history. Although, in some places, it’s hard to tell if a prayer pile was built 500 years or five minutes ago.

The word cairn comes from the Scottish Gaelic for hill or mound, but now the Scots too have had enough.

In May this year the National Trust for Scotland (NTS) blamed instagram-obsessed visitors for dismantling AD 563 stone structures on the island of Iona and vandalising the landscape. Stone piles left by mediaeval pilgrims were being picked up and rearranged to please the instagram sensibilities of 21st-century visitors.

Farmers have begun complaining their drystone walling - a common method of dividing fields on the outer islands - is being picked at and added to by tourists.

So what makes one pile of stones sacrosanct and another a blight on the land?

All in all it’s just another chip in the wall. (Hey, hiker! Leave them stones alone!)

There appears to be a lot of contradictions even among conservation movements. Beyond a knee-jerk reaction to preserving the landscape as we found it, why is it a question of old stones good, new stones bad?

One thinks a Hopi Indian gave little thought to the debate when he added another stone to the pile marking an Elk mustering route, while the pyramid of Giza was still waiting to be hewn out of an Egyptian quarry.

Across what is now the United States, native Americans have left their own cairns from 5000 years ago in what is now Rocky Mountain National Park. In parts of West Texas, there are burial sites marked by dry stone piles, even in areas where rangers are encouraging such piles to be dismantled.

Despite asking that visitors knock over any piles they find, the Yosemite National Park acknowledges that they serve a purpose “when used appropriately”, for navigation and safety.

“In general, rock cairns should only be constructed by rangers and trail workers.”

Even in New Zealand it appears the Department of Conservation has mixed feelings around the piles.

Earlier this year Wilderness Magazine constructed a very plausible April fools article from the matter, joking that DoC was introducing a stone stacking permit, “required for anyone wanting to construct cairns on public land”. If anything, it only added to the mounting confusion surrounding DoC’s position on the stones.

At the same time as conducting rock pile dismantling across popular hiking trails such as the Tongariro Crossing, in other parts of the country hikers are told such piles are important aids for navigation.

Trampers in Arthurs Pass National Park are advised to follow the “cairns” along unformed tracks. It’s probably best you don’t knock these over, as you go.