Jack. B Harrison and two colleagues bought the equipment from Sweetland and moved it to Alaska about 15-20 years ago, where they made compressed shafts with an Alaskan softwood. May have been some kind of hemlock as already suggested. Yielded an even heavier shaft than compressed POC. I believe Frontier was selling out its remaining stock. Isn't making anymore that I know of. Last I heard, the equipment was for sale.
Terry Bannit at The Footed Shaft had come across a good number of lower poundage original Sweetland POC Forgewoods recently. I believe he still has some for sale.
I've been hunting with them for years. Excellent shafts. The compression process enabled a higher spine and physical weight at a smaller diameter than regular cedar. Also, because the cedar billets/boards were often tapered before they were compressed and cut into squares for doweling, it yielded a naturally weight forward shaft which was also stronger behind the point than regular POC.
Harder to find than hen teeth nowadays.