over 9000, apparently.
It would be easier to know the weight of 1000 pieces. It takes about 17 trees (11 meters tall) to make about 1000 Kg of paper. I'm not sure how many trees does it take to make a 1000 pieces of paper.
About 8335 sheets
Thousands of pieces of paper can be made from a mature tree.
the average tree makes around 40,000 sheets of paper