How many sheets of a4 paper can be made out of a normal oak tree?

Question: How many sheets of a4 paper can be made out of a normal oak tree?
- Keywords:
  a4,
  paper,
  tree
Asked by Aleeeshyyy to Kate, Pip, Reka on 17 Nov 2016. This question was also asked by BOB.
- Reka Nagy answered on 17 Nov 2016:
  
  I don’t think you often make paper out of oak, because the wood is too hard – it is usually made out of softer wood that can be mashed more easily.
  
  But if we turned the average tree into paper, we’d probably get about 80,000 sheets of paper – but it depends on the size of the tree of course.

Question: How many sheets of a4 paper can be made out of a normal oak tree?