A tree was affected by salty solution (8)
I believe the answer is:
seawater
'solution' is the definition.
(I know that seawater is a solution)
'a tree was affected' is the wordplay.
'affected' is an anagram indicator.
'a'+'tree'+'was'='atreewas'
'atreewas' is an anagram of 'SEAWATER'.
'by salty' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for seawater that I've seen before include "Drink" , "Brine" , "What breaches dyke, perhaps" .)