I have been in the construction industry for 40 plus years.
The other day I was purchasing flooring for a project and the salesman told me that the flooring I was looking at came from a mill close by. He said that it was best to buy wood materials from your region because they would be used to the moisture swings. There would be less warp-age for framing and less seasonal change with flooring. I have never heard this before and am wondering how much truth there is to it. My thoughts are that it is a sales pitch for the weekend carpenter and he was just blowing smoke.