Now internet awareness spread across globe use as much as emails as communication mode than any other. Particularly business if they start using email as media for communicating invoices, statements etc will save trees and slows down de-forestation.
Avoid printing email:
Unless it is occassionally stop printing emails as it would have more impact than print media considering huge email users - business, industry, people at large from forms and fields
Spread environmental conciousness among masses with a message "Please consider the environment - do you really need to print this email?" in your emails.