Where should we get slash pine seed for Louisiana?

SLASH pine, like many of the early settlers, came to central and southwest Louisiana from east of the Mississippi River. It is flourishing in plantations 100 to 200 miles west of its natural range, which extends from South Carelina through the Gulf South to the eastern edge of Louisiana's Florida Parishes. In fact, it does so well that most planting on former longleaf pine land west of fthe Mississippi River is with this species.