New research by Forest Research estimates Great Britain’s trees contribute over £400m annually in benefits in the fight against floods.
Trees and woodlands have long been known to play a vital role in flood resilience, but scientists are now able to establish the financial contribution they make in protecting communities from flooding.
The flood regulation service of Great Britain’s trees, forests and woodlands as an annualised central estimate gave annual values of £843 million and £420 million compared to bare soil and grass, respectively. The valuation is based on the role trees, woodlands and forests play in intercepting rainfall, storing water and reducing the potentially devastating surface runoff that causes flooding.
Given the increased likelihood and frequency of extreme weather events as a result of climate change, the report highlights how woodland expansion can be a natural, cost-effective method of protecting homes and businesses – now and for the future.
Forestry Minister Trudy Harrison said, “Communities across the country know all too well the potentially devastating impacts of flooding – from damage to homes and businesses and the disruption of critical infrastructure to the tragic loss of life.
“This report provides the best picture yet of the integral role that our trees, woodlands and forests play in protecting at-risk communities from flooding. With more severe weather events forecast in the future, there is even more incentive to accelerate our tree planting efforts in line with our ambitious target to treble planting rates in England.”
Forests help to reduce flooding in numerous ways, in what is referred to as a ‘sponge effect’. Firstly, evaporation from leaves and branches helps to reduce the amount of rainfall reaching the ground. This process, known as interception, is significantly greater for woodland compared to other land use types. Secondly, the soils within forests receive, store and delay water, helping to reduce rapid run-off and peak flows. Finally, the presence of trees, shrubs and large woody dams along rivers and on the floodplain creates a barrier effect that slows the passage of flood waters downstream, in addition to delivering biodiversity benefits.
As a result, tree planting can significantly affect the volume, pathway and timing of surface run-off, reducing the risk of downstream flooding. Responsible forestry management practices help to maintain and secure this key environmental service.
Environment Agency Chief Executive, Sir James Bevan said, “The warning signs of the climate crisis are stark and mounting – with greater rainfall, higher tides and more violent weather bringing heightened risks of serious flooding over the years ahead. The hard flood defences which the Environment Agency builds and maintains all across the country are part of the solution. So too are Natural Flood Management techniques such as tree planting, which we are already using to slow the flow of water and help protect homes and businesses.
“By harnessing the power of nature, we can tackle the twin challenges of biodiversity loss and climate change – whilst simultaneously reducing the risk of flooding to vulnerable communities.”