Belo monte - The proposed Belo Monte dam will be one of the biggest in the world, but deforestation could limit the amount of energy generated

Deforestation in the Amazon region could significantly reduce the amount of electricity produced from hydropower, says a new study.

Scientists say the rainforest is critical in generating the streams and rivers that ultimately turn turbines.

If trees continue to be felled, the energy produced by one of the world's biggest dams could be cut by a third.

The study is published in the Proceedings of the National Academy of Sciences.

Many countries in tropical regions are turning to hydropower as an untapped source of energy. In Brazil around 45 new hydro plants are in the planning stage.

“We now have very strong evidence that Brazil's ability to generate electricity depends on forest conservation” Dr Daniel Nepstad

Rainforests, by their very name, are prime locations for the dams that are usually required to create the force of water needed to generate electric power.

Until now the presumption has been that cutting down the trees near a dam actually increased the amount of water flowing into the dams.

Trees of life

But in this new study the researchers took a broader look at the climate projections for the Amazon basin and not just at the rivers on which the dams were built.

They found that rainforests are more critical than previously thought as they produce the rain that fills the streams that ultimately drives the rivers and the turbines.