It's indicative of Holly showing age starting trouble by lough in Waterford (4,4)
I believe the answer is:
tree ring
'it's indicative of holly showing age starting trouble by lough' is the definition.
I can't tell whether this defines the answer.
'in waterford' is the wordplay.
I cannot quite understand how this works, but
'in' is within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for tree ring that I've seen before include "Mark of natural annual growth" , "Annual circle in a trunk showing its age" .)