The moisture content of any wood will change as the R/H does. The resins, etc have a chance to chrystalize in the wood cells after years of seasoning. I don't know the rate or if 10year old is as good/bad as 25 year old wood but I'd rather use a 2-3 y o piece over a 1 y o piece and a 10 y o piece over a 2-3 y o piece. Maybe it is a maturity thing...in the wood that is!
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Pearlie, this will be fun to watch. Keep us posted. Take your time and I'm sure you will produce a great bow with this special wood.