The prices of good boards are at an all-time high. The E.P.A. is shutting down the mills that make plywood. The timber companies have less old growth forest to choose from. Most of the affordable timber is being cut from new-growth pine. In the Midwest, the standard 2x4 is made primarily from spruce.
Boards made from cherry, oak, or poplar are expensive.
The easy solution to this lumber crisis is for the woodworker to make his own boards from the trees of his choosing. It took thousands of years for builders to move from throwing tree-trunks over two walls to arches and domes. It took thousands more before steel and concrete were used to create, in effect, bigger and better tree-trunks. I really hate frames. Though primitive, some of the info may well serve the survivalist in some situations.