Natural England Technical Information Note TIN093
Shelter woods to prevent wind
erosion
This note provides guidance on creating shelterbelts to prevent wind erosion, in
particular through Higher Level Stewardship (HLS) option HC10 Woodland Creation
outside Seriously Disadvantaged Areas.
About 2.2 million tonnes of topsoil are lost every
year in the UK because of soil erosion caused
by wind and rain. The costs of this include
approximately £9 million a year in lost
agricultural production as well as water pollution
and damage to aquatic environments.
Peat soils are a particularly significant store of
carbon and the erosion of peat soils speeds up
the release of their carbon into the atmosphere,
and this contributes to climate change, which in
turn has the potential to increase erosion rates
as hotter, drier conditions make soils more
susceptible to wind erosion. Trees can modify
local climates to protect soils and to benefit
crops.
Key points:
 Soil erosion by wind is a significant
environmental and agricultural problem.
 Climate change is likely to increase the risk of
wind erosion to soils.
 It takes time for trees to establish so plant
them now to create shelter belts for the future.
 Well designed shelterbelts can prevent wind
erosion, protect crops and provide other
environmental benefits.
 Good design is critical to ensure their
effectiveness.
 Sites must be chosen with sensitivity to other
objectives of Environmental Stewardship (ES),
for example, public access, biodiversity,
historic environment and climate change.
 Potential adverse impacts (for example,
turbulence and shading) must be considered.
© Natural England 2011
First edition 29 March 2011
www.naturalengland.org.uk
 Shelterbelts can be planted under the
woodland creation option: HC10 woodland
planting outside SDAs. Costs of planting can
be covered through HLS capital items,
including plants, guards and fencing.
 New woodland planting under ES must be in
blocks of no more than 1 ha, with a maximum
for the holding of no more than 3 ha.
 The Forestry Commission should be consulted
where more than 0.25 ha of trees are being
planted.
Wind erosion
Wind erosion of soil is a particular problem in
areas with light sandy, silty or light peaty soils.
These soil types are often suited to the
production of horticultural crops or other spring
sown crops where soils are cultivated into fine
seedbeds and are often bare in early spring.
Early spring is the most critical time for soil
erosion as wind speeds can often be high but
soils are drying out and becoming less stable.
Wind erosion results in:
 Loss of topsoil and its stored carbon.
 Loss of seed, fertiliser and agro-chemicals.
 Ditches filled with soil.
 Streams and rivers polluted by soil and agrochemicals.
 Damage to crops by abrasion.
 Soil blocking roads.
Natural England Technical Information Note TIN093
Shelter woods to prevent wind erosion
There are 3 broad types of shelterbelt:
 windshields;
 windbreaks; and
 hybrids.
Windshields
Windshields are densely planted areas which
are designed to create significant shelter, for
example, for livestock protection or around
buildings. This type of planting creates areas of
increased air turbulence around the planting
area.
Windshields may not be eligible for funding
under HLS if they are mainly planted for
commercial advantage and there are no
additional biodiversity or landscape benefits.
Windbreaks
Windbreaks are more open plantings which do
not stop wind but reduce its speed without
creating any turbulence immediately around
them. As wind speed drops humidity levels
increase. This combination significantly reduces
soils vulnerability to wind erosion.
Windbreaks are suitable for crop protection and
are likely to be eligible for funding under HLS.
Victorian-age shelterbelt of Scots pines in the Norfolk
Brecks
What is a shelterbelt?
Shelterbelts or shelter woods are narrow bands
of trees positioned to reduce the impact of wind
on crops, livestock or buildings.
The taller or denser the planting the greater the
effect on air flows. This modification of air flows
not only affects wind speed, but also turbulence,
temperature and humidity.
The density (porosity) of the planting controls the
reduction in wind speed and any subsequent
turbulence.
The height of the planting determines the downwind area of land affected by the reduction in
wind speed. Shelterbelts can provide downwind
protection of up to 20 times their height.
Hybrids
Hybrids are often planted with a dense lower
storey or scrub layer, but with a less dense
upper storey (mature tree height). This type of
planting achieves some of the benefits of both
windshields and windbreaks but without
significant turbulence problems.
Hybrids will only be eligible for HLS funding
when they are designed to prevent wind erosion
or if they provide landscape or biodiversity
benefits.
Benefits of shelterbelts
As well as protecting soils (a farm’s most
valuable asset) a well designed shelterbelt can
also provide other benefits such as:
 Increased crop productivity and more efficient
irrigation through localised increases in
humidity and temperature and reductions in
transpiration losses.
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Natural England Technical Information Note TIN093
Shelter woods to prevent wind erosion
 Re-establishing landscape patterns by being
positioned on the sites of lost field boundaries.
 Linking existing habitats, such as other farm
 Hiding unattractive farm buildings.
 Providing shelter for livestock.
woodlands or hedgerows.
 Providing new wildlife habitats.
 Benefitting farm game management.
Figure 1 The flow of wind over a shelter wood
Legislative impacts
An Environmental Impact Assessment (EIA) is
required for new woodland planting over a
certain size. Woodlands planted under HLS are
below this size limit and therefore on all but the
most sensitive sites new woodland planting
under HLS is exempt from EIA. See Further
information below for a link to details.
Once the trees in a shelterbelt have established
they cannot be removed without a Forestry
Commission felling licence. It is an offence to fell
trees without a licence if an exemption does not
apply. For details see Further information below.
Site selection
Shelterbelt creation is not suitable on areas of
existing high wildlife value or on sites that are a
priority for ground nesting birds or other openhabitat dependent species.
Shelterbelt creation should not be considered in
landscapes where woodlands would be
detrimental to landscape character.
Do not plant trees or shrubs on historic
features.
Sites will normally have soils that are sandy, silty
or light peats and that are vulnerable to wind
erosion ie in large, open and exposed areas. It is
expected that with warmer temperatures and
drier summers the vulnerability of sites to wind
erosion is likely to increase.
There can be reduced productivity immediately
around trees due to increased shading,
competition for water and possible turbulence.
These less productive areas can be put down to
another ES options such as buffer strips and this
should increase the overall value of the habitat
for wildlife.
ES options can also be used to enhance and
restore existing mature shelter belts. For
example by locating scrub and /or new tree
planting options adjacent to existing shelter
belts.
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Natural England Technical Information Note TIN093
Shelter woods to prevent wind erosion
Design considerations
Shape
Position
They need be no more than 20 m wide. Wider
belts will not necessarily provide more protection
(20 m width equates to 500 m of shelterbelt per
ha of woodland created).
Sites should fit in with the surrounding
landscape, for example by:
 Linking other habitats where possible.
 Re-creating old field boundaries (old
boundaries are often on breaks of slope or
mark changes in soil type so can be
appropriate places to plant).
To be effective they need to:
 Protect the most vulnerable parts of the field ie
areas of lightest soil, and the most exposed
topographically. Shelterbelts reduce wind
speeds upwind, as well as downwind.
 Protect from the prevailing wind, which
generally means planting at right angles to it.
In exposed locations protection from a range
wind directions may need to be considered and
in large fields more than one shelterbelt may be
required.
Wind will sweep over the top and around the
ends of a shelterbelt, providing a triangular area
of protection behind it, unless the ends of the
shelterbelt link in with other features. Wind
passing through gaps in the shelter or around
the ends can be moving faster and can
potentially be more damaging.
Shelterbelts typically protect an area downwind
of 20 times the height of the trees. Upwind the
area protected is 3 times the height of the trees.
Gaps should be avoided through shelterbelts as
they can channel air flows. If necessary arrange
a gap so that there is a dog-leg or so that it runs
at an angle through the wood.
Figure 2 The flow of wind across a ‘hybrid’ shelter wood (upper storey 40-60% porosity, lower storey < 40%
porosity)
Planting
Trees should be planted so that there is a
straight edge to the shelterbelt. Some air flow
through the shelter belt needs to be maintained
to prevent turbulence downwind.
Avoid shrub planting on the edges of the
shelterbelt, but an understorey of shrubs within
the shelterbelt will help to reduce wind speeds
whilst still allowing some air flow through.
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Natural England Technical Information Note TIN093
Shelter woods to prevent wind erosion
Trees should be planted in staggered rows
approximately 2 m apart.
See also the Forestry Commission’s:
Plant a mix of quick growing and slower growing
tree species to provide longevity to the shelter.
www.forestry.gov.uk/pdf/fcin081.pdf/$FILE/f
cin081.pdf
 Felling licence information at
www.forestry.gov.uk/forestry/INFD-6DFK86
 Environmental Impact Assessment (Forestry)
www.forestry.gov.uk/website/forestry.nsf/b
yunique/infd-6dfkbc
Plant shrub species that are quick to come into
leaf so will provide increased protection early in
spring when soils are likely to be most
vulnerable, for example, hawthorn.
Evergreens provide greater protection,
particularly in the winter, but non-natives should
be used with caution and only with the approval
of specialist advisers. Non-native nurse crops
should be avoided.
In particularly exposed areas temporary barriers,
such as lines of bales, can be used to protect
young trees during establishment.
Shelterbelts can either be fenced or individual
trees can be protected with guards, for further
details see information on HLS capital items.
Further information
Natural England Technical Information Notes are
available to download from the Natural England
website: www.naturalengland.org.uk.
 Principle for using woods for shelter
Authors and contributors
Thank you to everyone who contributed to this
note, in particular Max Hislop, Forestry
Commission, James Letts and Louise Webb,
Environment Agency and from Natural England,
Charlotte Lemmon, Ian Ball, Keith Kirby, Trevor
Mansfield and Sian Rudling. Editor Susie Smith.
Illustrations Paul Lacey (based on those in the
Forestry Commission note Principle for using
woods for shelter).
You may reproduce as many individual copies of this
note as you like, provided such copies stipulate that
copyright remains with Natural England, 1 East
Parade, Sheffield, S1 2ET.
© Natural England 2011
For further information contact the Natural
England Enquiry Service on 0845 600 3078 or email [email protected]
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