This: The cause of this increasing insensitivity of wood density to temperature changes is not known,

Is the key, if you have a divergence, you don't know about, you can't just get rid of it then pretend everything else is good. You have no solid verification of non divergence pre 1900 or so, yet we're acting like its fine. Dendoclimatology is a pretty weak science right now, I'm not sure why we're putting so much stock in it.