A devil's stovepipe or decomposition chimney is a hole formed when a tree, that has been buried by an encroaching sand dune, decomposes.
This cylinder of bark keeps the surrounding sand from collapsing in and thus creates a void, an unexpected occurrence in such an unstable medium.
Depending on the size of the tree from which it formed and its surface visibility, a devil's stovepipe may be quite dangerous.
For areas with large stovepipes there is a danger of suddenly becoming buried under significant quantities of sand.
Devil's stovepipes are mentioned as a hazard in the novel Sometimes a Great Notion by Ken Kesey.