Why should the state of Idaho (and others) claim ownership of the national forests? Because that was supposed to have been the action of Congress with the admittance of the territories as states; excepting only forts and associated defense-type properties necessary for the federal government to protect the citizens (see Article 1, Section 8, the last two paragraphs of the U.S. Constitution).
Regardless of any agreements made under pressure to become states (or the withholding of the same), the federal government should not have retained ownership of the lands within the states. The states should also be able to manage the forests better than the federal government does.
In my opinion, the federal agencies have, for the most part, become infested with environmentalists who want no human footprint in any of the forests. The result we are seeing is lack of good forest management, such as proper tree-thinning, controlled logging, uncontrollable wildfires and horrendous waste of good lumber – to say nothing of the destruction of the lumber industry.
Again, the feds bit off more than they could chew and now they simply cannot afford to take proper care of the forests that once produced substantial cash flow from logging.