
The forest rings have been mostly thought to be the results of radial increasing fungi within the root system of black spruce scientifically known as Picea mariana, and possibly the fungus is Armillaria ostoyae.
A ring might start as a single point of contamination and grow outward in all directions. Affected trees could die inside the centre of the circle, and eventually, new trees might grow in their vicinity. But the biological speculation is no longer favoured as there is little compelling proof to support that theory which makes it more weird and mysterious.