Mann claims that the tree rings quit working 50 years ago. The trees work fine, it appears to be some climate scientists who are the problem.
The green line is Briffa’s decline, which Mann hid. NCAR showed the same decline in the 1970s
GISS used to show the same decline for the US, before they “corrected” it away in 2000.
Looks like the hide and seek game extends beyond PSU.