It is claimed that prior to the 1960s, tree ring data matched thermometers within a few tenths of a degree. I don’t see much evidence to support that in the Briffa/GISS comparisons below.
There are lots of places where one shows cooler and the other shows warmer relative to the 1961-1990 baseline.
Briffa vs. GISS 1960. Both use baseline 1961-1990.
1950
1940
1930
1920
