Dendrochronology by Peter Ratcliff:
For this Gagliano, the latest visible ring on both sides is from 1769, however the two halves are from different trees.
Best cross-matches with the bass side are:
Vicente Assensio (Spanish, but generally got wood from the exact same provenances as 18th century Italians), followed by two separate Nicola Gaglianos one from c.1775, these three possibly from the same tree. Followed by M.Deconet, Joseph Gagliano, Silvero Ortega, J&A Gagliano, Antonio Bagatella, 1751 GB Guadagnini, Castello viola, etc..... all totally consistent with wood used in Italy at the time ( and by a few Spanish makers).
Best cross-matches with the treble side are:
Tomaso Eberle, probably Paolo Castello, Silvero Ortega, 1803 Giuseppe Guadagnini, G.Amati II, Nicola Gagliano, GB Gabrielli, M.Deconet, Nicola Gagliano, PA Dalla Costa