It said underwater since 1589- not that it started growing then. Dendrochronology is quite accurate in a limited geographical area. If the probably carbon rich water doesn't pollute the sample, then C14 could be used.
Note also the use of the word "estimated". If other methods were used (such as degree of mineralization) then I am positive that an estimate of the error would also be available, though the meaning of such statistics would get lost in a general interest article like this.
Note also the use of the word "estimated". If other methods were used (such as degree of mineralization) then I am positive that an estimate of the error would also be available, though the meaning of such statistics would get lost in a general interest article like this.