That map pretty much sums it up - there weren't close to the number of trees in the early 1900s east of the Mississippi as there is today. They'd been cut down to build homes, heat homes, removed for farming purposes, build furniture - any number of items. There is a lot more tree cover today than there was then. Most places where large stands of trees remained was not suitable for growing crops, which also meant not suitable for growing grass.
Does anyone have a resource for this assertion? I am surprised by the idea that tree cover would have increased in the US because of urban sprawl. I would guess the opposite.
I did a quick google search and only found a site discussing a 30% decline in tree cover in urban areas. It did not address whether a decline in farmland has led to increased tree cover.
These numbers come from here:
http://www.ncrs.fs.fed.us/pubs/gtr/gtr_nc241.pdfForest acres (thousands) by region:
North: 1907: 138,700 2002: 169,684
(North includes everything east of the Mississippi and north of the Mason-Dixon line.)
South: 1907: 235,728 2002: 214,605
(South includes the southern Atlantic states (VA, NC, SC, GA, FL), which have seen forest land increase from 1938 to today, and South central covering the rest of the southern states, OK and TX.)
Note, this is FORESTED land, which doesn't include planted suburban areas, which now often have tree replacement requirements in excess of what was on the property at any point in history!
No, I am not an "anti-environmentalist" or obtained it from some "skewed" source, unless you consider the US Ag department one of those two.