Dry stone walling turning green

[Topper]

Here in Lancashire there are thousands of miles of dry stone walling. I just happened to notice today that most of it has turned bright green, has anyone an explanation for this deliberate but natural vandalism?

 

[Channel Hopper]

Won't be there for long.

(You could try making soup out of it)

 

[Analoguesat]

Bird cr&p - its the nitrates in it promoting algae growth.

 

[Lazarus]

Lichen?

An unexplained effect of the absence of proven man-made global warming?

 

[Analoguesat]

Might also be nitrate rich rainfall

 

[Channel Hopper]

A wall not far from a pub ?

 

[Low Profile]

Maybe the effect of dust from Eyjafjallajökull.

 

[Topper]

A wall not far from a pub ?

Aren't all walls not far from a pub?

 

[PaulR]

Maybe the effect of dust from Eyjafjallajökull.

Easy for you to say!

 

[Channel Hopper]

Easy for you to say!

Relevant though

_http://www.gastroshark.com/fjallagrasamjlk-iceland-moss/