06 Dec Shelterbelts

Farm Shelterbelts

In partnership with FWAG SW, Protect Earth and Ecologi

In 2020 we eagerly volunteered to offer our farm as a demonstration site for the “Optimum Shelterbelt”.  The design of the “Optimum Shelterbelt” is the result of many, many years of research by John Davis in conjunction with Oxford University.  In partnership with this project, the Organic Research Institute Cirencester will be evaluating the benefits provided by these shelterbelts.  The establishment and the results of these trials will be critical to demonstrate how this type of tree planting could be funded in the future under the new Environmental Land Management scheme.

The “Optimum Shelterbelt” which are linear copses designed to provide maximum possible shelter lea-side of prevailing wind, extending to 20 times the height of the tallest row of trees. In addition, shelterbelts if strategically placed can help to conserve water and diminish flooding, link habitats, prevent soil erosion, enhance biodiversity and noise avoidance.  Carbon sequestration is also an important benefit.  Two sites on the farm have been chosen for the trials, one in the highest and most exposed area and the other at a lower altitude on the western boundary of the farm.  Both sites border arable fields where there are poor hedges and dilapidated stone walls.  Preparation of both sites includes removal of scrub elder and overgrown hawthorn and blackthorn and removal of antiquated fencing.  The shelterbelt extends to 5m in width into the cultivated arable field which has made planting much easier.  The trees and shrubs are all planted with tree shelters and stakes for support and protection against hares and rabbits The plan below shows the overall design.

The four rows of closely spaced fast growing trees and shrubs will grow at different rates to different heights.  It is designed to have open areas between trees, branches and leaves to a ratio of about 50%, as any more than this will allow wind to whistle through lower areas and conversely a lesser percentage created by dense foliage can cause turbulence as the wind effectively hits a brick wall and is thrown up and over the trees.  The idea is to filter the wind. The aerodynamics of wind flow is a surprisingly complicated business!

To ensure that the trees grow away quickly it is important to make sure they are kept well weeded in the first 5 years.  We are planning to experiment with different methods using mulches, strimming and/or spot spraying.

The research that will be carried out will measure effects on animal welfare (when the arable rotation goes into herb ley and will be grazed by sheep), the effect on arable crops in terms of yield and plant health as well as changes to the biodiversity such as increased numbers of birds using the shelterbelt for nesting feeding etc.  Water management evaluation such as ‘run-off and infiltration rates will be measured and soils analysed.  All this information will be used to create a database of benefits to persuade the grant bodies to fund planting of shelterbelts.  Currently there is no funding available as it falls between a hedge planting grant and a small woodland grant.

Find out more about all of the projects at Lower Hampen Farm on our projects page HERE.

More information about the FWAG SW can be found at: https://www.fwagsw.org.uk

Discover more about the work of Project Earth at https://www.protect.earth

Find out more about Ecologi and get involved at https://ecologi.com