Land Use in the United States

My friend Denise Maxwell sent me this link to Land use in the United States statistics. One thing that caught my eye is that 18% of our cropland is used for something other than field or vegetable crops.  Some is in CRP, some is in pasture, some is failed crops.  Have we maxxed out on acreage available for corn production?  I don't think so.

Another thing is see in the statistics, is the amount of range land in the country.  How can we quit eating meat when we have so much land available for livestock production that is not good for anything else.  Release of greenhouse grasses by ruminants?  I say no net change in historic levels because wildlife such as deer, elk, and Bison have always been releasing greenhouse gasses in North America.

Forest is the leading land use in our country.  The demand for forest products is always there.  I am curious about how much of the forest land is available for harvest under current government policy.  How much of the forest land is un-harvestable because of terrain?