Some of the ancient forests in places like Shilin, China, are unique not for their trees, but their rock formations. Researchers, long fascinated by the natural phenomenon, recently looked into how these structures are formed.
The Stone Forest in China and others like it are the result of hundreds of millions of years of seismic activity and erosion. The Chinese forest covers about 100,000 acres.
The rocky landscape, also called karst, is made of a variety of rocks such as dolomite, gypsum, and limestone. Culturally, the rocks have significance, such as the rock of Ashima—a symbol of hope for freedom to choose who to marry.
Ashima is a legendary woman who was forced to marry someone she did not love and was later rescued by Ahei, her lover. As they fled, a flood swept their lives away, and stones formed upwards from the earth to symbolize her life. Her story is celebrated annually at the Torch Festival.
World's Largest Stone Forest
The Tsingy de Bemaraha Strict Nature Reserve in Madagascar is the world's largest stone forest. Some of the rock formations rise as high as 230 feet from the ground. 'Tsingy' roughly translates to 'where one cannot walk barefoot' in the indigenous Malagasy language.
Some of the eroded limestones are not just rock towers but have forest canyons and caves underneath and act as shelter to various flora and fauna. Nearly 200 million years ago, a bed of limestone formed underneath a lagoon until tectonic activity eventually pushed the rock above sea level.
READ: Archaeologists Finally Discover the Origins of Stonehenge
Candy Simulations
A team of researchers published a paper in the journal Proceedings of the National Academy of Sciences explaining new findings on the origins of stone forests. Their study may help with future designs of pointed structures like probes and micro-needles for medical or other scientific purposes.
"This work reveals a mechanism that explains how these sharply pointed rock spires, a source of wonder for centuries, come to be," said Professor Leif Ristroph from New York University's Courant Institute of Mathematical Sciences. The team conducted several experiments and simulations to demonstrate how flow, mimicking erosion, can carve landforms to create sharp spikes.
Professor Michael Shelley, from the Courant Institute, shared that the research also explains why karst topography is not only composed of soluble rocks, but also pinnacles that are sharp and pointed.
At the university's Applied Mathematics Lab, combining a mathematical model, automated simulations, and a block of solid candy displayed how dissolving rocks created flows and reshaped the formations.
The sugar-based candy has pores that are reshaped into pointed spikes after being dissolved. The team found it interesting that they did not have to design the flow of water since the dissolution process naturally has flow patterns that produces spikes.
In the same way, karst rocks dissolve, but a lot slower during the time that minerals are submerged underwater. When the water recedes, it results in stone forests and rock pinnacles.
READ: How the Heavy Rains of Hurricane Maria Shattered the Forests of Puerto Rico
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