This document summarizes the results of machinery trials for coppicing hedgerows conducted on two farms in December 2014 and February 2015. It found that manual felling was the slowest and most expensive method, while assisted felling using excavators was faster and less costly. Tree shears mounted on excavators and circular saws attached to tractors also performed well. Large scale chippers were more efficient than small scale chippers. With grants, savings from reduced flailing, and selling woodchips, certain methods could be profitable. Coppiced hedgerow woodchips were found to be a low-cost fuel source. Further opportunities and next steps are discussed.
12. Tree Shears
1 man team, 10” Dymax tree
shears mounted on 9t
excavator
Three finishes:
• Tree shears as cut
• Chainsaw finish (short)
• Chainsaw finish (long)
35. Woodchip Production
at Elm Farm
Actual fresh volume/mass at 47% MC
Average of
0.26 𝐦 𝟑/0.08 tonnes/84.12kg
per metre of hedge
42.5 𝐦 𝟑/14.3 tonnes/14300 kg
harvested from 170m of hedge
36. Woodchip Value
*HWFC Hampshire Woodfuel Co-operative, based on Feb 2015
rates
£1.50
£3.84 £4.09
£14.39
Estimated open
market value
Private sale to
HWFC member
Sell to HWFC, as a
member
Sell to a self
supplier
Net profit £/m3
37.
38. Let’s take the best case
scenario …
£14.39 per 𝐦 𝟑
+ large scale
chipper + minimum of 300m of
hedge
39. Savings made on reduced hedgerow flailing
With a flailing cost of £1 per metre
and assuming we side flail only every 3 years
A potential saving of
£13 per metre over a 20 year hedgerow coppice rotation
* £1 per meter is based on contracting bills and information from flailing contractors for a large west country
hedge 3-4m wide (Dickenson, R. 2014).
40. Countryside Stewardship grant
Hedgerow coppicing (BN6)
£4 per metre
On hedges over 20m long, less than 5m wide and
composed of at least 80% native shrubs
41. Method Net Cost/
Profit (£/m)
Net Cost/ Profit
(£/m) Inc. flailing
savings
Net Cost/ Profit (£/m)
Inc. flailing savings +
coppicing grant
Manual Fell 1 (EF) -9.43 +3.57 +7.57
Manual Fell 2 (EF) -5.86 +7.14 +11.14
Manual Fell (WAF) -9.02 +3.98 +7.98
Assisted Fell -4.20 +8.80 +12.80
Tree Shears -7.15 +5.85 +9.85
Tree Shears + Chainsaw -8.27 +4.73 +8.73
Circular Saw 2 -4.00 +9.00 +13.00
Circular Saw 1 -6.41 +6.59 +10.59
Felling Grapple -7.48 +5.52 +9.52
43. Fuel + Method Pence per Kwh Comments
Hedgerow woodchip self
supplied (large scale chipper)
1.6 – 3.1 Depends on which harvesting method
( does not include transport cost as
self supplying)
Hedgerow woodchip supplied
(small scale chipper)
2.8 – 4.2 Depends on which harvesting method
( does not include transport cost as
self supplying)
Bought in wood chips (30% MC) 3.1* Mean UK price for bulk order of 10
tonnes
Bought in logs (30% MC) 3.5* Based on bulk delivery of 1 tonne
Wood pellets 4.4* Mean UK price based on bulk order of
5 tonnes
Natural gas 4.9*
Heating oil 5.8*
LPG (bulk) 6.5*
Electricity 15*
* Figures taken from DHG publication ‘Wood Fuel From Hedges’ 2014
Comparative Energy Costs to a Customer
44. Where next?
RHI payments?
Farmers making use of
existing resources and
machinery?
A supplementary
enterprise?
Other grants and funding?
Demonstration/best
practice sites ?
Editor's Notes
We have carried out trials at two locations using 5 different machinery options to coppice hedges:
These are: Manual fell; Assisted Fell; Tree Shears; Circular saw and a Felling grapple
Which we will now talk you through …
So this is the hedge at Elm Farm
It’s a 20-30 year old hazel coppice with blackthorn out-growth
On this hedge we trialled three harvesting method in short trial sections which you can see in the diagram here ….
The hedge is located on the south side of a small road.
The trial design was influenced by the availability & cost of specialist machinery, the ground conditions and therefore good direct access to the hedge from a road or track.
Timing of hedgerow coppicing is difficult where the work has to be carried out from the fieldside, because the legal window is 1st September- 30th April, however best practice restricts this window at both ends by the presence of leaves on the hedges until November (late November in 2014) and the start of the bird nesting season in March. This is set against the wet ground conditions of winter when soils are most vulnerable to rutting, poaching and compaction. Late winter or early autumn are preferable in terms of ground conditions, if the other issues can be got around.
This is the hedge we coppiced here at Wakelyns.
As you can see it’s a much older, bigger hedge with some well established maple trees and thorn
Again here’s a diagram of the trial sections at Wakelyns – it’s a green lane. As the hedge wasn't that consistent we had slightly shorted sections.
We also had 2 circular saw sections as the character of the hedge was very different on the two sides of the hedge…
So back to Elm Farm ….
First up was the Manual fell - a 2 man team, one with a chainsaw & the 2nd extracting & moving the material
Their method was to have one cutting and one dragging the material – hard work !
Next was the Assisted Fellers - 2 man team, one with a chainsaw & the 2nd on an 8t excavator supporting the stem being felled & moving the material
The assisted fell method worked exceptionally well, but is a high risk method which requires a high level of trust, confidence, skill and experience in the 2 man team for it to work safely. This is not a method for novices.
Here’s a short video of the two … - very impressive father and son team!
Lastly at Elm Farm was the Tree Shears - 1 man team with 10” Dymax tree shears mounted on a 9t excavator
Here you can see the shears working on the thin hazel – not ideal for this machine!
The angle at which the tree shears coppiced the hazel stools at Elm Farm may have aided the visibility of the cutting bar, but created pressure on the stool which caused root rock and an unknown impact on the coppice regrowth. This machine is designed to work optimally on single stem trees.
Explain method and observation
Quick mention of the cut finishes – Here we can see the tree shears where it has splinted into the stool
Now on to Wakelyns
First up was Circular saw: a 2 man team, one on a tractor with a side arm-mounted circular saw, the 2nd clearing the material, usually from another tractor with a fork
Very effective at siding up brambles - not so good with big trees …. Un predictable and fall on cab !
The circular saw works optimally on consistently small diameter material such as the short rotation coppice at Wakelyns. It doesn’t cope very well with very large diameter or very tall trees/shrubs because of the lack of control of the direction of fall.
Next up was Felling grapple: a 1 man team with a Gierkink felling grapple mounted on a 5.5t excavator
Impressive bit if kit
Operator not used it before …
The felling grapple, although very manoeuvrable, ended up leaving some stems cut quite high because it couldn’t get to the base of the stems.
Coppicing methods where the operator sits in an excavator or tractor will always be limited by their visibility of the coppice stool, and their flexibility to coppice each stool on an individual basis, whereas a manual chainsaw operator can adapt easily to the site, ground conditions, size of timber and position/shape of the stool/tree, particularly where aided by an excavator or tractor with fork to hold the tree/stool and move the material.
We then tested 2 chipping methods at EF - small and large scale chippers !
Not a drum chipper?
BIG kit ! - caused a lot of damage as ground conditions were poor …..
Fast !!!
Much slower …. And labour intensive !!! Difficult to pull material out of the piles …
Also had to watch out for root balls as would blunt the chipper blades!
Advantage to doing the feeding by hand as we could separate and cut them off with the chainsaw
WE are yet to proccess te matierial at wakelyn – we’ll disscuss this outSide when were at the hedge
Here at Wakelyns we will also be trialling 2 different methods of processing the hedgerow material:
Chipping all of the hedgerow material to create woodchip
Separating the cordwood from the brash down to 5-10cm diameter, & then processing the cordwood into logs for firewood and chipping the brash to create woodchip (this should just be brief and we can talk about it outside!)
Peter Frizzell’s Jenz drum chipper
Right ! On to the numbers !!!
We collected data on the time taken for each section of hedge to be coppiced & the material chipped or processed, the cost of both coppicing & chipping/processing, the fuel used, the ease of the operation and the quality of the finish.
The coppice regrowth will be monitored to see if there are any noticeable effects of the method of coppicing.
This is an overview of the average time taken per meter of hedge cut for each harvesting method.
These times include sharpening/ refuelling
The bars show Standard deviation.
Interesting to see the variability in the 3 manual fell sections – I would put this down to character of the hedgerows
The hedges at Elm Farm and Wakelyns were of a very different nature from each other, so the harvesting times per metre are not directly comparable.
Time wise assisted fell beats the rest – though would this still be the case with less experienced fellers? Probably still fastest
Can also see the variability in the two circular saw times – much better suited to SRC material NOT big trees!
Some contractors perhaps worked slower than they might have done on a big job or if they had had more experience of the machine, while others hardly had any breaks, so calculating the average length of hedge each machine/coppicing method could cut/harvest in a day is difficult because you have to take into account re-fuelling and chainsaw sharpening time and breaks, as these are all part of a contractors work day.
Here we can see the cost per m of hedge cut based on an 8 hour day with 1 hour break time ( this is likely to be a slight over estimate as doesn't include any faff and chat …)
Costs DO NOT include VAT !
You can see with the larger machines that haulage can increase the cost substantially
The availability & cost of specialist machinery; the more specialist it is, the more rare/less available it is & generally the greater the transport costs to get it to site, which means the amount of hedge coppicing work has to be large enough to make the increased costs worthwhile.
Assisted Fell is by far the cheapest of the methods tested at EF on the hazel coppice
And Circular saw used on coppiced hazel at Wakelyns ( although a much thinner hedge than EF) was the quickest at Wakelyns and overall
Here are the mean chipping times for the large and small scale chippers.
Here you can see the large scale wins hands down even with 3.5 people working with the smaller chipper
Similarly – the large scale chipper wins on the cost front too
Again these costs DO NOT include VAT or haulage and based on an 8 hour working day accounting for 1 hour of break time
So how much chip did we produce?
The chip was then stored in a barn green – and is still there! – took 3 months to dry to ~35% so now probably at 30% and ready to sell …
To get idea of how much our chip is worth and to find some potential buyers we approached the HWFC and a self supplier.
So if we were to sell to the HWFC as a member and factored in transport and membership fees we could get around £4.09 per m3
If we sold to the HWFC via a member we would be looking at 3.84 per m
Our woodchip consultant at HWFC also put forward the market value of tree surgeon chip which is the closest to our chip at £1.50
And lastly a local farmer with their own boiler who currently self supplies put forward the figure on £14.39 based on what he can produce his own chip for – transport. - a self supplier willing to pass the benefits of RHI payments
~£100 tonne
he MC not specified in quotes by buyers so based on m3 not weight
estimated volume of woodchip to sell 57.32m3 harvested at 45-50% MC, stored in barn & sold at 30% MC
SO When you factor in hire cost of harvest and possessing which methods came out top in our trials?
And does it make economical sense to harvest and sell the woodchip or are you better off using it yourself?
So based on an ideal scenario where we get the most for our chip and used the most economical chipping method …
Dose it make sense to sell chip from hedges?
Assuming an annual cost of £1 per meter to flail a hedge and assuming we side flail every 3 years for 20 years
Potential saving of £13per meter over a 20 year hedgerow coppice rotation
This accounts for an annual cost of flailing at £1 per meter resulting in £20 per meter on a 20 year rotation.
If we side flail a hedge intended for woodfuel every 3 years and allow for 7 side flails over 20 years it would reduce this saving to £13 per meter.
Available for:
Hedgerows and boundaries capital grant
Mid Tier
Higher Tier
Can only be used on planted boundary lines of shrubs that are:
over 20m long
less than 5m wide between major woody stems at the base
composed of at least 80% native shrubs
Sep into ef and waf cs 2 into ef
No not really ….
What this shows is that even if you could sell the chip for £14.39 and used a large scale chipper and the most cost effective harvesting methods we trialled you would make a significant loss….
£ including haulage!
So lets look at the pure energetic value rather than the chips market value …
Markets; this hedgerow woodfuel product is suited in every way to on-farm use, where it can avoid the snobbery of the required quality for saleable woodchip (as with firewood logs), as well as the cost of haulage to a depot/woodfuel hub or customer.
It is a low value high volume product which is optimally used as locally as possible
These are not looking at transport or market
There are a number of limitations to the trials which we’ll discuss in more detail later
And We still have a lot of work to do on these costs ….
How does receiving RHI payments change the feasibility of producing chip from hedges?
What if you factor in the savings made by reducing the frequency of flailing?
What if woodfuel production was supplementary to your business – like Ross Dickenson in Dorset?
Are the subsidies or grants available for restoring hedges? Mostly for capital investments such as machinery
Leader and countryside productivity scheme (defra)
Supplementary enterprise – dove-tailed into other income streams and seasonally
Saving on transport and machinery hire costs - farmers self supplying with access to machinery can make better use and take advantage of exsiting resources: yard space, tractor, trailer, machinery, storage
