Topics: How reliable is carbon dating?
(1.) C14 dating is very accurate for wood used up to about 4,000 years ago. This is only because it is well calibrated with objects of known age. Example: wood found in a grave of known age by historically reliable documents is the standard for that time for the C14 content. This standard content of C14 can then be used for wood not associated with a historically documented date. Dates up to this point in history are well documented for C14 calibration.
For object over 4,000 years old the method becomes very unreliable for the following reason: Objects older then 4,000 years run into a problem in that there are few if any known artifacts to be used as the standard. Libby, the discoverer of the C14 dating method, was very disappointed with this problem. He understood that archaeological artifacts were readily available. After all, this what the archeologist guessed in their published books.
Some believe trees are known to be as old as 9,000 years. They use tree rings as the calibration standard. A lot of people doubt this claim for various good reasons I wont go into here. We believe all the dates over 5,000 years are really compressible into the next 2,000 years back to creation. So when you hear of a date of 30,000 years for a carbon date we believe it to be early after creation and only about 7,000 years old. If something carbon dates at 7,000 years we believe 5,000 is probably closer to reality (just before the flood).