Hi Chris
The NCPTT has an article entitled "A Grading Protocol for Structural Lumber and Timber in Historic Structures" and a MS Access database at
http://ncptt.nps.gov/a-grading-protocol-...-2009-01/all/1/The database is somewhat limited in the number of species covered but it may be useful in a site survey.
You may find a resource in the NCPTT since it is located in Louisiana.
National Center for Preservation Technology and Training
645 University Parkway
Natchitoches, LA 71457
Email: ncptt@nps.gov
Phone: (318) 356-7444