Don’t ever base a theory on just one tree.
There is evidence of many pole reversals on the bottom of the Atlantic Ocean. When looking at the Iron on the sea floor, it is aligned in different directions—North and South. If you were to color one direction white and the other black, the pattern would look like a zebra.
It is a fairly regular event and nothing to really get worked up about.
That's not what they are doing here. Notice it doesn't say that the field reversal was discovered, it says that a tree which lived during the time period of the field reversal was discovered. The reversal(s) of the Earth's magnetic field throughout history have been known for some time. The discovery of this tree is just about finding a very specific snapshot of that reversal taking place.
It's as if there was a story saying, "Video of Hillary Clinton deleting 30,000 official emails has been found." The video is a more detailed corroboration of something we already knew.
Isn’t the AGW hockey-stick theory based on five (5) tree ring samples?
(Never mind the other ~78 ring samples in the age-grouping that don’t indicate AGW...)