You said,”Surprisingly enough, global warming doesn’t seem to be the cause of the problem. (I was really expecting that to be blamed.)”
Hmmm... it kinda was in a roundabout way:
Last sentence of the article:
“Bongers said it is very possible that climate change is affecting these trees. He currently has a research project underway and hopes to have an answer within two years.”
A few years and a few tens or hundreds of thousands of grant dollars should result in a definite 'maybe' regarding climate change's effects.
I saw that and thought “No”, that’s just an excuse.