Prince Charles is expected to call for better protection of the world's forests at the UN climate conference in Paris.
He will condemn corporations which, he will argue, appear not to care if their business activities result in forest destruction.
About a billion people depend directly on forests for their livelihoods.
Negotiators from 195 nations in Paris seek to reach a deal within two weeks to reduce global carbon emissions.
The agreement is aimed at limiting global warming to 2C (3.6F).