Marc, if that stave was 20 years old, do you do anything to prevent bugs? I live in Utah and work mostly slippery elm and Siberian elm saplings, when I do elm. Even when I dry staves very dry and fast by roughing them out, and sometimes even after I have heat-treated, I get these TINY borers of some type that eat the staves either under the bark or even between growth rings. I would thing heat treating would kill any larvae or eggs, but it happens a lot if I leave wod int he garage too long. first I know I am finishing front profile or somethign and I start to see powdered wood fluffing out. Or, I have even had a sudden "delamination" between summer wood rings, only to see little squiggles all over the separated surfaces.
I can usually cut elm, hack it out and finish in few weeks including drying, but sometimes I want to cut wood in fall for the winter. But I'd rather not have to work wood coated with pesticides. Ideas?