Approximately somewhere between 3 billion to 6 billion trees are cut down per year. Since density of trees varies by forest type, the 3 billion to 6 billion figures are rough estimates.
The loss of forest area can be attributed to logging and tree harvest for paper, construction and other products. It is easier to trace the amount of area lost by a forest than it is to calculate the number of trees that were actually cut down. Forests contain anywhere from 50,000 to 100,000 trees per kilometer, which means 60,000 times 50,000 and 60,000 times 100,000 equates to anywhere from 3 billion to 6 billion cut down trees.