Since the invention of Radiocarbon dating in 1949 scientists started to recognize various problems with radiocarbon dating from the labs to the samples being submitted.
For instance the preliminary samples tested by Emory and Sinoto who raced to determine first contact had rather large standard deviations, reflecting the crude solid-carbon counting methods first used by the pioneers of the radiocarbon dating method.
However a sample from Waiahukini was interpreted as beginning around AD 750 which now formed the basis of a claimed first discovery.
Testing continued at sites around Hawaii to find the earliest dates.
The problem, of course, was that such samples in many cases included old growth timber, which had an “in built” age that was potentially much older than the time at which the wood was actually burnt in the hearth or oven.
Therefore, the date returned by the radiocarbon lab may have been an accurate indication of the age of the timber, but not of the “target date” of human use of the site.
With the invention of radiocarbon dating archaeologists immediately scoured the islands in search of the earliest possible samples.
Chronologically that put the first voyages and settlement of the islands occurring around AD 965-1065.
Further because coastal sites were common, there was also the likelihood of older drift wood was used for fuel with age already built in.
Accordingly, in the early 1990s scientists began a taxonomic identification of wood charcoal based on anatomical characteristics by comparison to a reference collection of known woody plant species for the particular region or island which allowed scientists to refine their samples for testing further.
Over the next ten years the early radiocarbon dating of Hawaiian samples started to return dates suggesting sometime first humans arrived sometime between 300 AD to 800 AD casting doubt on Pu‘u Ali‘i sand dune sample.
Accordingly, it was retested with the help of a second lab and to their dismay could not be replicated and was instead revised to roughly 1000 to 1350 AD.