Ok, that's plainly idiotic (and false.) But here's the delusional part ... Limbaugh was citing this as an example of the "liberals" not being able to face reality if it conflicts with their political ideology since he made this claim in the mid 90s and was refuted*
LIMBAUGH: "Do you know we have more acreage of forest land in the United States today than we did at the time the constitution was written." (Radio show, 2/18/94)There is some kind of psycho-pathology involved here. Rush is a nihilistic relativist capable of believing anything if it suits his political purposes. It's both amazing and disturbing, you can actually hear him on the radio making up reality as he goes along (e.g. they didn't know how to put out forrest fires is why there was less acreage then). And there are millions of people who take what he has to say as gospel and a political movement that attempts to curry favor with this buffoon.
REALITY: In what are now the 50 U.S. states, there were 850 million acres of forest land in the late 1700s vs. only 730 million today (The Bum's Rush, p. 136). Limbaugh's claim also ignores the fact that much of today's forests are single-species tree farms, as opposed to natural old-growth forests which support diverse ecosystems.
*Plenty of other absurdities at the link. My personal favorite is Rush saying that there are more native Americans alive today than when Columbus landed or at any time in history.