Sculpting stone forests

Landforms are readily recognized by their stereotyped shapes, but their formation processes are often hidden in geological history and involve complex interactions between flowing fluids and solid but shapeable boundaries. Spectacular examples are so-called stone forests, which are found worldwide and consist of thousands of tall, upright pillars of dissolvable mineral rock. Using candy as a stand-in for mineral in lab experiments on dissolution, we show that forests can be 'grown' under surprisingly simple conditions. We also focus on a single tree in the forest, and boundary layer theory modeling shows how dissolution-generated flows 'lick' and reshape the pillar into a singularly sharp spike.