Planting trees around rivers could reduce the height of flooding in towns by up to 20%, new research suggests.
A study for the Environment Agency concludes that trees round a feeder stream can slow the rush of rainwater and save properties from flooding.
But it warns that natural flood prevention methods do not always work.
And it urges a strategic approach because foresting a whole catchment would be counter-productive.
The report - from the universities of Birmingham and Southampton - says that with increased building on flood plains and climate change increasing the risk of heavy rain, many places can't be completely protected by walls of concrete.
There has been a rush of interest in natural methods - planting trees and creating leaky dams which attempt to delay the flow of water by creating mini-floods upstream.
But the report's authors suggest that most successful natural methods are likely to be on a much larger scale than currently in operation.
They advise a strategic approach - taking a tributary stream to a main river then foresting the area round it, allowing the stream to make its own meanders, and letting dead wood from the forest to block the stream where it will.
A drop of up to 20% in flood maximum can be achieved by doing this over 25-40% of the main catchment, they say.
That is because the forested area will release its water to the main stream later than water running off pastureland. (BBC)
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