Dendrochronology is an accurate dating method. It is good to within a year.
Regarding ddchr accuracy, a wiggle match can nail down a pretty accurate date, but in practice artifacts can’t be dated that accurately (one year).
More about dendrochronology:
http://www.pbs.org/time-team/experience-archaeology/dendrochronology/
As long as we’re on RC dating, this always bugs me when it appears:
“The wood used for its construction was cut down in the years 913 and 914..”
“The tree was cut down in 980, during the reign of Duke Mieszko I, the first documented ruler of Poland.”
Unless bark is present, the radiocarbon date doesn’t and can’t show anything of the kind (apart from an unverifiable coincidence).