Responsible stewardship of the forest resources. There are many different certification schemes, but the best and most-inclusive are the FSC (Forest Stewardship Council), PEFC and the SFI standard. These systems are based on inspections and auditing by third parties.
Confederation of European Paper Industries (CEPI). Members commit to set up and use reliable verification/tracking systems and use third-party certification chain-of-custody to document the wood flow. Legal Logging Code of Conduct