Summary
Strategically located woodland can be important in reducing flood
risk, improving water quality, contributing to biodiversity conservation, storing carbon and
helping support sustainable farming practices. It is these multiple benefits which make it such a
compelling option. Thoughtfully integrated into farming systems trees can have direct benefits to the farm whilst
also delivering flood mitigation. This paper is taken from a blog by Jim Waterson, Crop and
Environment Sciences, Harper Adams University. The full version which includes links to reports
referred to here can be accessed at:
http://www.harper-adams.ac.uk/news/202121/our-world-view-the-role-of-trees-in-managing-floodrisk#. Uwr8L9GPOCq
Flooding has highlighted the importance of land use in managing
flood risk. The extent to which water is held in the upper catchment and the speed with which it moves down
the catchment both have an impact of the risk and severity of flooding. A review of water and
farming has provided evidence for the role of trees in managing water quality and flood risk.
Forest Research has also undertaken research looking at the role
of trees in delivering better water quality and the impacts of increased tree cover on flood risk.
Often however, the arguments have become polarised with calls to remove sheep and reforest the hills. These
arguments fail to recognise the importance of farming, economically and culturally, to large parts
of the country. They start from the false assumption that flooding is an inevitable consequence of sheep
farming.
Lessons from Pontbren
The Pontbren farmers in mid-Wales show not only that flooding is
not an inevitable consequence, but that sustainable management of sheep can contribute to flood
mitigation. During the last 10 or so years, the group of farmers managing more than 1000 ha of the Pontbren
catchment have restored hedgerows, planted new hedges and shelter belts and invested in the
management of their woodland. This has provided vital shelter to allow a switch to outdoor lambing and
less need for housing. It has also provided the opportunity to exclude sheep from steep areas and from wet
areas prone to foot rot and liver fluke. New hedges and shelter belts, particularly those across the slope,
have increased water infiltration into the soil and reduced erosion and the loss of valuable topsoil and
nutrients. Planting tree belts across the slopes led to increased water infiltration into the soil more than
60 times that of neighbouring pasture. When this effect was modelled across the catchment the result was
a potential reduction in peak stream flows of as much as 40%.
This farmer-led initiative shows that an intimate knowledge of the
land is vital in designing tree belts. The farmers knew where shelter was needed, where runoff was a problem
and areas prone to erosion. They have managed simultaneously to improve the resilience and
sustainability of their farms whilst delivering improved water quality and flood mitigation.
Thoughtful use of woodland
At the beginning of the process, the farms had just 1.5% tree
cover; now 5% is trees. This has been achieved without loss of productivity. Not a wholesale
transformation of the uplands, but a sensible change in practice with trees integrated into the farming. There
are undoubtedly opportunities in the uplands for more extensive areas of new woodland, but the answer
is not removing farming. In Wales, 80% of farmland is classed as upland. These are generally small
family farms central to the survival of communities and an essential element of Welsh culture and
language.
Alan Spedding, 24 February 2014
www.arthurrankcentre.org.uk/images/1930_Trees_sheep_floods.pdf
RuSource
There are different opinions:
BBC - Learning Zone Class Clips - Changing landscapes - sheep grazing - Geography Video
Feral | George Monbiot
See also:
Futures Forum: Peaslands Knapp... meadows and sheep
Futures Forum: 'A Farm For the Future'
Futures Forum: 'Mega farms'... for Devon...?
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