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Renewable energy: Why burn US trees in UK power stations?

27 May 2013 Last updated at 20:57 BST

Environmentalists are trying to block the expansion of a transatlantic trade bringing American wood to burn in European power stations.

The trade is driven by EU rules promoting renewable energy to combat climate change.

Many millions of tonnes of wood pellets will soon be shipped annually to help keep the lights on in the UK. Other EU nations may follow.

Critics say subsidising wood burning wastes money, does nothing to tackle climate change in the short term, and is wrecking some of America's finest forests.

The BBC's Environment Analyst, Roger Harrabin, explains the process and examines the impact of the policy.

Produced by the BBC's Ted Metzger, Ian Druce and Bill McKenna