Reducing flood risk by planting trees: Rewilding

There are two main reasons for flooding: heavy rainfall and how land and rivers react to heavy rainfall.   Improving soil structure and drainage through planting and cultivation provides a long-term deterrent to flooding.  Tree cover greatly increases the rate at which rainfall is absorbed by the soil, soaking it up quicker and slowing down the rate by which it flows across the ground, reducing standing water and backflow into rivers.

Rewilding and reducing flood risk

So – it makes sense to plant new trees, woodlands and hedgerows and choose the best plants for the job, right?!  That’s where rewilding comes in.

Flooding and planting – what do we know?

  • Planting trees around rivers could reduce the height of flooding in towns by up to 20% says a study completed for the Environment Agency and published in the journal Earth Surfaces Processes and Landforms.
  • A study in pastures in mid-Wales estimated that reforesting just 5% of the land reduces flood peaks by around 29%.
  • The same study demonstrates that full reforestation reduces the impact of flooding by 50%.
  • It is a combination of reduced livestock grazing (reducing the effects of animals compacting the land when grazing) and tree planting (which aerates the soil and allows water to filter through it like a sponge) that alleviates the flood risk.
  • Planting new trees on grazing land speeds up the water infiltration in the soil (the sponge effect) by 67 times.

major study by Forest Research, a Forestry Commission arm, found that planting trees near watercourses and on hilly land could be major factors in reducing flooding and the resulting soil erosion and water pollution.

There is a need to increase incentives for woodland planting by making these better reflect the full range of water and other benefits.” – Forest Research

Rewilding for woodland and your garden

All the studies point to more planting=less flood risk and this is true in the natural landscape as well as your own garden.  This “rewilding” isn’t just restoring the natural balance with plants, it’s about letting nature look after itself alongside people and wildlife.  The benefits are plenty but topped by cleaner air and water, better flood control and a yearning for more beautiful trees and natural corridors in the countryside.

  • More planting = better aeration of soil = less soil erosion = less flooding
  • More plants = more insects = more birds = more wild animals

In a nutshell, rewilding helps restore nutrients to the soil, provides for pollinating insects, purifies water, reduces flood risk and helps resist droughts.  That’s a win-win-win-win-win!

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