Harvesting trees The FSC(Forest Stewardship Council), SFI(Sustainable Forest Initiative), PEFC(Programme for the Endorsement of Forest Certification), and other bodies certify paper made from trees harvested according to guidelines meant to ensure good forestry practices. .The number of trees consumed depends on whether mechanical processes or chemical processes are used. been estimated that based on a mixture of softwoods and hardwoods 12 metres(40 ft) tall and 15-20 centimetres(6-8 in) in diameter, it would take an average of 24 trees to produce 0.9 tonne(1 ton) of printing and writing paper, using the kraft process(chemical pulping). .Mechanical pulping is about twice as efficient in using trees since almost all of the wood is used to make fibre therefore it takes about 12 trees to make 0.9 tonne(1 ton) of mechanical pulp or newsprint.