Tree rings and C14

At https://malagabay.wordpress.com/2016/04/08/irish-guide-to-the-first-mill… … purports to show that C14 dates prior to 600AD are unreliable as a result of a cosmci event. The detail is missing and one is referred to various earlier posts on revising AD chronology he has made. It would be extremely interesting if C4 diverged from the tree ring graph – even if it was not to the extent he envisages. Somebody else might like to explore the issue.