Since these “long-term” samples may introduce the “old wood” effect, any calculation of precise absolute dates based on “long-term” samples is unreliable and may easily lead to errors of up to several decades or even more.
But it is much more useful regarding broader archaeological periods.
The differences in the various dates for the transition from Iron I to Iron IIa are too small to be helped much by radiocarbon dating.
This question is sharpened in light of the fact that the uncertainty in the usual radiocarbon readings (plus or minus 25 years or so) may be as large as the difference in dates in the debate. Measuring the remaining carbon-14 content in “long-term” organic samples, such as wood, will provide the date of growth of the tree, rather than the date of the archaeological stratum in which the sample was found.
Furthermore, wooden beams were reused in later strata, which can result in even greater differences in date.
For all these reasons, contrasting dates have been reached in the ongoing chronological debate concerning the Iron Age.