The United States contains 8 percent of the world's forests. This is 21st century and trees growth are on a decline, but that isn't the case in the US. According to the Food and Agricultural Organization, “Forest growth nationally has exceeded harvest since the 1940s. By 1997, forest growth exceeded harvest by 42 percent and the volume of forest growth was 380 percent greater than it had been in 1920."
This is a great news for our world, especially for the United States, we really have to appreciate that how a completely-developed country maintains their environment. It is not a miracle, it is due a number of factors including conservation and preservation of national parks, responsible tree growing within plantations.
About 65% of the forest land in the United States is privately owned, and many landowners are leaving their land intact instead of using it for agriculture. This tree planting effort was begun in the 1950s. And the most important thing is - The average age of forests in the United States is younger than it was before. No need to tell how useful a tree is.