Wood is a local, regional, or a shipped from far away product. If you are fortunate enough to live where the trees grow you usually can get what you normally can about any time. In Ohio Ash is down due to Ash borer, and we are past the initial glut on the market. There are some that bought really cheap, and are hoarding like you never will ever see it again (think Chestnut) South of us I don't know how heavy Ash was/is, but there is still some South, and if they have much Ash there will be a glut anywhere the bugs to, and kill off the trees, so for some years you can still get it, just might not be local. Walnut has been affected by Thousand Cankers disease, and I think it must be spotty, because I have not had issues sourcing Walnut, and prices have been pretty stable here.
Probably a lot of the absence of wood at Gilmer may be a lot of the woods that got reallllllllllly popular, are becoming illegal to import, because the third would countries they came from offered nothing in conservation.
Interesting read about that As we know the USA has a tendency to do things with some modicum of conservation, and we usually agree to rules governing such things. Asia, maybe not so much.....
There is a ton of info online, if you named a species, I'm certain you could track it to see why it is no longer available to you, or at least in your local area.