From Pieter De Waal
How about the following theory about the “fairy circles” in Namibia (3 April, p 12)? In the past, land may have been cleared of unwanted trees, shrubs or weeds to turn the land into more friendly pastures or for the planting of crops. The removed vegetation was then stacked in heaps, left to dry and ultimately set on fire. Noxious substances captured in the plants, with or without the influence of the heat created by the fire, concentrated in the ash and poisoned the earth below. On the periphery, ash from lighter vegetation such as grass and shrubs acted as a fertiliser causing more luscious growth.
I would suspect that the noxious plant could have been a substantial tree which was chopped and burnt where it fell. Lighter vegetation would then be carried to the site of the fire and added to the periphery. I have noticed similar “fairy circles” in the vicinity of Darling, about 100 kilometres north of Cape Town.
Gordons Bay, Western Cape, South Africa
