Free state,

Long Leaf (along with loblolly, shortleaf, slash, and virginia pine) is a species that falls under the lumber category "Southern Pine" or occasionally "Southern Yellow Pine (SYP)". Current design values are available here ...
http://www.spib.org/timbers.shtml?/publications.

There is another category "mixed southern pine" that has lower design values because it allows a few of the poorer species to be included.

If I remember correctly, you only need 6 rings per inch to meet the "dense" requirements. Any first growth timber should meet that. (I've seen over 30 rings per inch in it).