The answer to your question is, 500KM.
Wear<span> away</span><span> or change the appearance or texture of (something) by long exposure to the air</span>
Considering how large of a GDP the US have, I would agree with such a move. There's several reasons why I would agree on such a move. One of them is of course the well being of the nature, as it is crucial for the survival of every living organism, including the humans. Reforestation will bring in lot of benefits that will gradually return the investment. For starters, the air quality will improve, and by doing so, the health problems among the people will reduce significantly, thus much less will be spent on healthcare. Part of the new forests can be fruit forests, which will be an enormous reserve of organic food without having to use any labor or effort in production. Also, by establishing forests, whole ecosystems will get back on the scene, so lot of useful plants can be harvested from the forests, such as herbs and mushrooms. If the US makes a deal so that it can use certain part of the benefits from the forests until it gets its enormous investment, it will be a win-win situation for everyone. In order to have the budget for the global reforestation, it would be the best to cut down on the budget for development of weapon of mass destruction and the budget for war.
