Concerning the sequence of rings derived from the bristlecone pine, Ferguson says: In certain species of conifers, especially those at lower elevations or in southern latitudes, one season's growth increment may be composed of two or more flushes of growth, each of which may strongly resemble an annual ring.
ICR creationists claim that this discredits C-14 dating. Answer: It does discredit the C-14 dating of freshwater mussels, but that's about all.
Kieth and Anderson show considerable evidence that the mussels acquired much of their carbon from the limestone of the waters they lived in and from some very old humus as well.
The older an organism's remains are, the less beta radiation it emits because its C-14 is steadily dwindling at a predictable rate.
So, if we measure the rate of beta decay in an organic sample, we can calculate how old the sample is. Question: Kieth and Anderson radiocarbon-dated the shell of a living freshwater mussel and obtained an age of over two thousand years.
It is easy to correlate the inner rings of a younger living tree with the outer rings of an older dead tree.
The correlation is possible because, in the Southwest region of the United States, the widths of tree rings vary from year to year with the rainfall, and trees all over the Southwest have the same pattern of variations.
Living organisms are constantly incorporating this C-14 into their bodies along with other carbon isotopes.
When the organisms die, they stop incorporating new C-14, and the old C-14 starts to decay back into N-14 by emitting beta particles.
However, the amount of C-14 has not been rising steadily as Cook maintains; instead, it has fluctuated up and down over the past ten thousand years. From radiocarbon dates taken from bristlecone pines.