[CedarDave]

Use of tree-ring data as a method to determine past summer temperatures is bogus, whether used by Michael Mann (Dr. Hide-The-Decline) or those who are trying to debunk man-made global warming. We don't win points in the climate change war when our science is as bad as their junk science.

Trees don’t represent temperature and half a year doesn’t represent an annual record.

See also comments at this link:

Roman World Was Hotter than Thought

[CedarDave]

Sorry, correcting link:

Roman World Was Hotter than Thought

The latter thread was included because of the discussion of improper use of significant figures in calculations.