Scottish Highlands folklore tells that, before a battle, soldiers would each place a stone in the shape of a tower at the top of a hill, and when the battle had finished, all who survived would return and remove a stone. Those stones that remained were left as a cairn to honour the dead.
Across the centuries and continents, cairns have been used as waymarkers, to mark summits, as memorials to fallen friends, as markers of a religious place, or, more recently, just as proof of having wandered by. The forest provides a perfect environment for building cairns as they are less likely to be disturbed when built off the beaten track and can be left as a secret memorial to mark a special occasion.
In some places, building stone towers is illegal as it disrupts the natural stone landscape. In other places it is frowned upon because it can confuse walkers who read the stone towers as waymarkers and get lost. In order to not create a potentially disorienting cairn for a pack of unsuspecting ramblers, stone towers bordering paths should be dismantled before being abandoned.