There are more trees in the U.S. than there were 100 years ago
mnn.com
mnn.com
https://www.google.com/maps/place/Oregon,+USA/@43.8637703,-1... - you can see that there are more trees in the more recently clear cut sections, and fewer in the older growth. Also, replanted sections tend to be a monoculture of whatever commercially viable species is favored in an area.
It's easy to see land ownership from the satellite images:
https://www.google.com/maps/place/Oregon,+USA/@43.7673552,-1...
Forest service land to the east has been logged, but not quite as extensively as the mixed private and BLM land to the west. The checkerboard pattern is created by that mix of BLM and private land: http://en.wikipedia.org/wiki/Checkerboarding_%28land%29
In the last few decades chipboard furniture and managed tree farms further reduced deforestation.
Keep in mind that the conditions US colonists found in the US: a massive, dense, virgin forest were not natural. The massive depopulation of native peoples allowed forests to grow thick and create the illusion of an uninhabited land. Normally people manage the land, usually unintentionally from just living on it.
I believe another reason is that the introduction of the railway shifted food production to the plains and California. New England used to be farmland for much of the US.
See http://www.bostonglobe.com/metro/2013/08/31/new-england-sees... :
> Today, 80 percent of New England is covered by forest or thick woods. That is a far cry from the mere 30 to 40 percent that remained forested in most parts of the region in the mid-1800s, after early waves of settlers got done with their vast logging, farming, and leveling operations.
> Some of the revival can be credited to aggressive environmental efforts ... But the return of forests has mostly been a matter of economics: As New England became more citified and industrial, and food from western states became cheaper, there was less reason to maintain open land — much less blast every wild critter that might nibble a crop or gobble a goose.
In the plain states, large rows of tree were planted for farming (e.g. shelter belts). Many places trees exist today did not have trees pre-farming. This was the great plains, not a forest region.
If farming is no longer viable then humans are no longer viable.
At the same time, the midwest, especially the great plains area, were always tree sparse.
Details (Selected Results of the 3rd National Forest Inventory): http://www.bmel.de/SharedDocs/Downloads/EN/Publications/Fore...
* http://www.mnforsustain.org/united_states_population_growth_...