I believe wood is an extremely common source of radiocarbon dates. What type of samples are you referring to then?The results I refer to aren't derived from samples of the sort you're talking about here. Hence, your objections are not applicable to these findings.
Well given we don't have a time machine, the only way of analysing carbon 14 levels from the past is to measure the remaining carbon 14 in samples today and work backwards. But to work backwards, you need to know the date the sample was formed. And that is generally done by using the 'known' chronology of the civilisation from which the sample is taken. Therefore, you cannot use that to then 'confirm' the established chronology of that civilisation, because then you're just working in circles.As for differing amounts of 14C in the atmosphere, we actually know a lot about that but I will comment a bit more about it below in response to a different poster.
How do you suppose the levels of carbon in the atmosphere in ancient times can be measured without presupposing the date of the artefact which is being analysed?