Audel's Carpenter & Builder Guide (Volume 2) Copyrighted 1929 has a list of weights for various timbers. White pine is listed as 3.5 lbs/bd ft "green from saw", 2.5 lbs/bd ft "dry", 2.4 lbs/bd ft "well seasoned", and 2.2 lbs/bd ft "kiln dried". I've used these numbers for years and haven't had a truck overloaded yet (knock on wood).
