The European Union reached an agreement with the Republic of Congo to halt illegal timber imports to the 27-nation group and label wood that’s harvested with methods that keep tropical forests intact.

The African nation sends about half of its $330 million worth of timber exports to the EU, the European Forest Institute said today in an e-mailed statement.

Tearing down forests accounts for about a fifth of all carbon-dioxide emissions, according to the United Nations Environment Program, or UNEP. Trees that would consume CO2 are hauled to mills, or lie decomposing, releasing greenhouse gases.

Under the agreement announced today, wood exported from the Republic of Congo to the EU will require a license proving it has been harvested in a way that doesn’t harm the country’s forests. The EU will help monitor and enforce the rules.

The EU is negotiating similar agreements with other tropical timber producers including Indonesia and Cameroon, and reached an agreement last year with Ghana as part of an effort to combat global warming and protect plants and animals.

Forests also contain “significant” non-timber resources and contribute materials for the $43 billion annual herbal medicine market, according to UNEP. Illegal logging results in about $15 billion of lost revenue each year, mainly in government taxes.

Over the past 15 years, the world has lost 50,000 square kilometers (19,305 square miles) of primary forests a year, UNEP has said.