Why farm hedge trimming needs to change

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Posted Jun 13 2019 by Peter Hull of Natural England
The result of farm hedge trimming in a photo by Bob Embleton via Wikimedia Commons

Destroyed habitats, blocked drains and that’s just for starters. After decades working to support farming and agriculture in various government agencies, Peter Hull shares his views on why farm hedge trimming needs to change.


I have always felt strongly for a long time now that the practice of neatly topping and trimming hedges wastes valuable fossil fuels and also degrades habitats for wildlife. Hedges alongside the highway must be trimmed for safety reasons but there are probably tens of thousands of miles or kilometres of internal farm hedges which need not be so aggressively trimmed. There are several benefits to the environment in doing so.

Energy saving

Going back a few decades, hedges were trimmed using a 35 hp tractor with a mechanically belt driven cutter bar. Now we see tractors of over 100 hp trimming hedges with hydraulically powered flailing heads. Transmission of power by hydraulic transmission is hugely inefficient. To compound the inefficiency, flails are a blunt tool for cutting wood. The inefficiency of cutting hedges and wasting valuable fossil fuels across the UK is huge.

Blocking drains and subsequent localised flooding

The other problem with this type of machine is that, although it shreds the woody material and most of the shredded material drops into the hedge itself, some of the shredded material ends up on the road. This gets washed into drains, blocking them and causing localised flooding. There is a need for a different design of hedge trimmer that is kinder to hedges, makes cleaner cuts and clears up any material from the roads.

Degradation of wildlife habitats

Not only is the whole process hugely inefficient in the use of energy, but it destroys wildlife habitats. Flails are often too blunt and just abrade the wood, leaving a very ragged cut which, as any gardener will tell you, leaves the hedge susceptible to disease and degradation. Very often the tops and sides of farm hedges are cut so aggressively that the woody thorny plants do not survive and brambles and bracken invade the tops and sides of banks of hedges.

Shade and shelter for livestock

In livestock areas taller hedges provide shade and shelter for stock. If the predictions of global warming are realised and the temperature increases, shade and shelter for stock will become more necessary. Another good reason for not topping hedges so aggressively or not topping them at all, if they can be laid traditionally, is that they produce some wood from thinning the hedge at the time of laying it.

The cost analysis of trimming versus laying

It would be interesting to look at the cost of no or reduced annual trimming as opposed to laying a hedge say every 10 years to 15 years, depending on altitude. The costs of labour and machinery in both cases would need to be assessed to prove if the reduction in labour and machinery for annual trimming is any more (or less) than laying a hedge over a longer time period. The benefit of any renewable resource would also need to be taken into account.

Biomass

The country as a whole and the farming industry are missing a valuable resource. If farmers could be persuaded to manage their hedges differently it could generate a valuable renewable resource: biomass. There are some notable good examples on Exmoor, where laying hedges has always been traditional. It is the farms which have little or no support through government schemes which tend to resort to trimming hedges excessively because they probably feel that allowing them to grow up and outwards causes them a lot of work and expense in future years.

Providing examples of good practice

In the absence of any encouragement by the authorities, I do wonder if wildlife groups could be more proactive and find farms which are less aggressive in their trimming regime and promote these practices and benefits to other farmers. Even better if they could find several neighbouring farms who may be persuaded in one locality to improve hedges say over a wider area and enhance wildlife habitats.

Conclusion

There are several issues here that could be corrected in ‘one hit’ by different hedge management techniques. It is not easy changing farmers’ minds, I know. I firmly believe, though, that an improved design of hedge trimmer, combined with maybe side trimming hedges but not topping them could reduce fossil fuel consumption and a saving in fuel and cost. It may also generate some income from biomass as a renewable resource. Ultimately, however, it would help to reduce global warming and at the same time improve wildlife habitats.

As a retired employee of Natural England, please be aware that Peter’s views do not represent or necessarily reflect the current views and policies of Natural England.


About the author

Peter Hull began his civil service career as a Mechanisation Adviser for the Agricultural Development and Advisory Service (ADAS), later converted into the Farm and Conservation Agency before falling under DEFRA, and undertook various roles there. Prior to retirement, he worked as a Project Officer with Natural England, dealing with the Environmentally Sensitive Area Scheme on Exmoor.