It is difficult to answer.
In both cases the subject does not do the action as there is the auxiliary "be". And there is the past participle which can be considered as an adjective.
Actually I cannot state it is or not.
In the 1st sentence you cannot replace "be" by "have". "It has called a tree" means nothing.
In the 2nd sentence I think you can replace "be" by "have". "Much of the Artic HAS gone" does not sound wrong, in my opinion.
So may the 1st sentence be passive and the 2nd not ?
I often wonder that when I meet this kind of sentences.
Just a thought.