Inhibition of lichens - The handrail has been there for over a decade.
A curved bare band on the footpath parallels the curved handrail because water has dripped from the handrail and deposited lichen-inhibiting zinc leachates onto the footpath. In the enlarged view you can see many brownish lichen thalli on the footpath, mostly away from the drip zone but with some beginning to colonize the margin of that zone.

Photographer: Heino Lepp