Flooding and the ecological solution

In the aftermath of the extensive flooding in Eastern Scotland and Northern England over the Christmas and New Year period it is time for governments and land owners to take the re-forestation of our uplands more seriously.

Trees for Life believes that the root of the flooding problem lies not in the perceived lack of investment in flood protection for downstream areas but in the upper catchments of our river systems. This is not a new idea and has been the subject of research over the last couple of decades… so why have things not changed?

It is clear that the heavily grazed and intensively burnt moorlands devoid of native woodlands which dominate our hill landscapes are unsustainable if we wish to avoid future flooding problems. As climate change is making intense weather patterns increasingly commonplace we must act now to begin the process of forest restoration at catchment levels across Scotland and England. It is no coincidence that the headwaters of the Dee, Don and Tay – the most recent rivers to flood – are dominated by heather moorland, sheep pastures and older non-native plantation forests which have been intensively drained.

All three land uses tend to accelerate the rate at which water moves from soil to stream and on downhill, causing the flooding in major towns and cities we have recently witnessed across the country. The problem is an ecological one – soils and vegetation in vast areas of Scotland’s river catchments are now incapable of holding onto water and releasing it slowly (“the sponge effect”), and we need an ecological solution: more natural levels of grazing and browsing that encourages woodlands and other habitats to develop in our uplands.

The problem is an ecological one – soils and vegetation in vast areas of Scotland’s river catchments are now incapable of holding on to water and releasing it slowly

Research has shown that woodland soils are 60 times more effective at soaking up rainfall than compacted sheep-grazed pasture soils. However, the impact of hundreds of thousands of red deer and literally millions of sheep on our hills means that woodland recovery is currently impossible over large areas of Scotland. Voluntary agreements on deer management have failed to dent the inexorable rise of red deer numbers over the last 40 years. Coupled with the management of large areas of eastern Scotland of grouse moorland by burning, a perfect storm of environmental issues has been allowed to develop. Much more needs to be done by landowners and government to tackle this now to mitigate further flooding in the future. Reducing red deer populations, encouraging natural regeneration of woodlands and reducing historic drainage impacts on moorlands and planted forests would be a good start and a step in the right direction.

References: 

Nisbet, T.R and Thomas, H. 2006. The role of woodland in flood control: a landscape perspective

SPICe Briefing. 2013. Wild Deer in Scotland

Defra. 2004. Review of impacts of rural land use and management on flood generation