They inferred a "NEAR reversal" NOT "Magnetic Field Reversal"!!!!
Second, Nobody explains the uniqueness of finding a 40,000 year old tree that HAS NOT BEEN PETRIFIED!!!!!!
Third, they don't explain how the tree rings revealed changes in the Earth's magnetic field.
Almost reversed, because all the magnetic pole shifts have been random amounts. The magnetic pole used to run through Arabia, for example. IOW, the headline isn't misleading at all.
Petrification takes some length of time, or is a sudden process related to short-lived events (the latter would be suggested if this turns out to be an entire forest's worth of trees).