Geoff sends us a post about "the 'strange phenomenon' of naturally-occurring 'forest rings,' or circles up to 2km in diameter only visible from the air, in northern Ontario. The rings are at least partially caused by electrochemical effects in the soil — which are apparently strong enough to affect the local water table, such that 'the water is being held up against gravity,' as geochemist Stewart Hamilton discovered. This is 'beyond science fiction,' he gushed."
In effect, their shape is expressed from below. For ambitious future landscape designers, note that this implies a potential use of plantlife as a means for revealing naturally occurring electrical networks in the ground, where soil batteries and other forms of terrestrial electronics could articulate themselves through botanical side-effects.
That is, plant a forest; come back after twenty years; discover vast rings of negative electrochemical charge like smoke rings pushing upward from inside the earth.