Fungus On Pyramid Cedar Hedge Trees - Vancouver Island

[TMA_VI]

Greetings,

 

We have had 3 pyramid cedar trees in our hedge die on us. We wonder if the cause was the fungus shown in the photos or alternately if the initial cause was due to rabbits chew damaging the bark during Winter months. We noticed some similar fungus, to a lesser degree, on other trees in the hedge that appear to be still healthy.

 

Please offer some free preventative advise for this (these) problem(s).