TWECOM best practice guide on hedgerow harvesting and machinery

TWECOM BEST PRACTICE GUIDE ON

Hedgerow Harvesting Machinery and Methods

inhoud1. Introduction .............................................................................................................................1 1.1. Target audience ...........................................................................................................12. Woods versus hedges .............................................................................................................23. Hedgerow harvesting machinery and methods .....................................................................3 3.1. Harvesting, felling or coppicing hedgerows ................................................................3 3.2. Stockpiling and transporting the hedgerow material .................................................5 3.3. Processing the hedgerow material by chipping .........................................................5 3.4. Transport .....................................................................................................................7 3.5. Storage and drying ......................................................................................................7 3.6. Further processing of hedgerow woodchip ..............................................................114. TWECOM Hedgerow harvesting machinery trials ................................................................12 4.1. Case study: Roadside hedgerow tree harvesting in Bocholt ....................................12 4.2. Case study: Harvesting timber from landscape elements in Limburg Province .....15 4.3. Case study: Dyke-side alder row harvesting in West Flanders ................................155. Post-harvest hedgerow care.................................................................................................19 5.1. Gapping up hedgerows ..............................................................................................19 5.2. Hedgerow tree development .....................................................................................196. Conclusions ...........................................................................................................................20

Contactgegevens ABC Eco2 [email protected] tel 016 28 64 64 www.agrobeheercentrum.be

1agrobeheercentrum Eco2

1. INTRODUCTIONThis best practice guide describes the experiences gained through the TWECOM Hedgerow Woodfuel Project, which has researched the feasibility of harvesting woodfuel from hedgerows. Through this project, we have looked to optimise the logistics of the whole harvesting process, from felling trees and coppicing hedges, finding suitable places to store and dry woodchip, right through to burning the hedgerow woodchip in a woodfuel boiler. In order to optimise every stage in the process, you need to consider the hedge and your situation. You need to choose the right machine which is appropriate for harvesting or coppicing the type of hedge you have, the scale at which you are going to harvest, and the type of woodfuel boiler to match the woodchip you are going to produce.

This Best Practice Guide This guide has been produced based on the experiences, knowledge and findings gained from hedgerow harvesting machinery trials carried out under the TWECOM Project. These were carried out by Agrobeheercentrum Eco2 and Inagro in Belgium and by The Organic Research Centre in the UK. The results and guidance given here are however largely based on the trials carried out by aagrobeheercentrum Eco2 in the Bocholt district of North Limburg in Belgium.This best practice guide begins with a description of the harvesting and processing machinery, and

the techniques that can be used to produce wood-chip for bioenergy from hedges. There is already a lot of information and research on the use of woody biomass for energy production, however most of this is based on experience gained from harvesting timber from woodlands. Then the harvesting and processing machines chosen for the Bocholt pilot area and the experiences gained in working with these machines are discussed. The harvesting of black alder rows by Inagro from West Flanders in Belgium is then discussed. The experiences, results and recommendations which came out of the hedgerow harvesting machinery trials carried out in the UK by The Organic Research Centre can be found at http:tinyurl.com/TWECOM. The aftercare of coppiced hedges is considered at the end of this guide.

1.1. TARGET AUDIENCEThis best practice guide is aimed at:• Hedgerow owners, landowners and farmers• Woodchip boiler owners • Land management agencies, such as local au-

thorities and landscape and nature conservation organisations who are interested in reducing their hedgerow management costs through the local valorisation/harvesting and use of hedge-row woodchip.

• Landscape and forestry contractors

2 agrobeheercentrum Eco2

2. WOODS VERSUS HEDGESThere is already a lot of information and research on the use of woody biomass for energy production, however most of this is based on experience gained harvesting timber from woodlands. There are however considerable differences between hedges and woodlands. Growing conditions are different; hedges receive more light and therefore grow more side branches, hedges have fewer trees or shrubs per hectare, and the harvesting conditions are dif-ferent; there is generally better access to hedges and many of them run alongside roads, but there are also more obstacles such as old wire fences and houses within and near them. Hedges and woodlands are both important for biodiversity, but they provide different wildlife habitats, and hedges have a key biodiversity role to play through creating a network of corridors which connects wildlife habitats. Hedgerows have always been character-ised as being a much more dynamic habitat than woodlands and should continue to be.For a long time now, hedges have not been regard-ed as land for timber production. This is explained by the following specific points.

There are few opportunities to produce quality wood from hedges: the trees and shrubs branch out much more than in a woodland situation, making it very difficult to produce nice long, straight and branch-free stems.The brushwood needs to be cleared up: there is often not enough space to leave the high volume hedgerow material from roadside pruning and coppicing next to the hedges. The chipping of

hedgerow material on roadside verges is both time-consuming and often undesirable from an ecological perspective. When hedgerow manage-ment work is done under contract, it is generally not permitted for the brushwood or woodchip to be left by the hedge. The use of hedgerow woodchip or biomass for energy production is therefore an ideal use for the wood from hedgerows. This provides the opportunity for every bit of coppiced hedgerow material to be used, and the whole-tree hedgerow material can be chipped in one go.

Hedgerows have an important wildlife corridor function:

If we consider an individual hedge, then the management or harvesting of hedges by coppicing should be phased over several years, ie a coppice rotation established. For example, a maximum of 1/4 of the length of a hedge or short sections of 100m maximum should be coppiced at any one time. However for each landowner and in each year, only a very limited length of hedge would be available to harvest by coppicing. The small loads of woodchip produced would be difficult to sell, and the hire of machines to harvest such small sections of hedge would be prohibitively expensive and not cost-effective.By working at a landscape scale, hedges do not need to be considered on an individual basis, where only a short section of one hedge can be coppiced each year, but rather as part of a wider network of hedges, where several hedgerows can be harvested at once. Having a good hedgerow network ensures that the corridor function of hedges can still be delivered even where some hedges are coppiced. By working holistically at the landscape level, the productivity and efficiency of hedgerow harvesting can be increased sensitively and sustainably. This obviously requires a lot of planning and preparation in getting all the neces-sary planning permissions and felling permits in place, communication with hedgerow owners and their neighbours, and sourcing suitable, adapted and mobile harvesting and processing machinery.

Figure 9. Natural drying of woodchip through self-heating.

© A

BC

EC

O2


3. HEDGEROW HARVESTING MACHINERY AND METHODS

There are several different stages involved in the process of going from a hedge to a building that is heated with wood chips. For every stage in the process, there are several different types of machines available. In order to make the best choice of machine for your specific situation, this guide aims to give an overview of those that are available.

3.1. HARVESTING, FELLING OR COPPICING HEDGEROWS

3.1.1. CHAINSAWA chainsaw is the basic piece of felling equipment. Although there are many models available, they mainly differ in horsepower and in length of the cutting bar. Even when other more specialist ma-chines are being used to fell trees such as a tree harvester, more often than not it is still necessary to have a chainsaw to hand. It is a good old simple chainsaw that is needed to cut back a tree stump, to fell large trees or coppice small shrubs cleanly, to cut back a roadside branch or to cut off a root ball and prevent it from going through the chipper.The main drawback of a chainsaw is that it is very slow in relation to mechanical harvesting, and that where larger trees need felling, a machine is really needed to move and place the whole trees, otherwise they would need to be cut up in situ. The advantage however is that a chainsaw can be used anywhere.

3.1.2. FELLING HEADWhen using a machine with a felling head, a tree can be felled entirely mechanically, without the need for any manpower. A felling head can be mounted on an excavator arm or the front end loader of a tractor instead of a bucket. There are many different machines and combinations of ma-chinery which can be used to fell trees and coppice hedges mechanically. Here the aim is to describe the main features of these harvesting machines.

Mounted on an excavator or tractorThe choice of base machine for the felling head is determined by the ground conditions where it will be working: paved roads, wet ground etc. In woodlands or wet/marshy areas a tracked exca-vator is most appropriate, whereas on the roads a wheeled excavator or tractor would be better. The total weight of the machine is also very important as most felling heads will allow an entire tree to be harvested at once; therefore the machine must be strong and stable enough to handle the weight of the felled tree.

Cutting mechanismThere are three different cutting mechanisms available in felling heads to fell trees and coppice hedges:Chainsaw: an integral chainsaw cutting bar comes out from the felling head and cuts through wood in a very similar manner to a manual chainsaw. The advantage is that it gives a good clean cut. This

Figure 3. Felling head with integral chainsaw cutting bar, similar to the Mecanil XG220 energy wood head (www.mecanil.fi).

© O

.R.C

.


cutting mechanism is very useful when cutting multi-stemmed shrubs or trees, such as coppice stools. The disadvantage is that chainsaws require a lot of ongoing maintenance, such as sharpening. However, because there are many moving parts in this type of felling head, there is a high chance of damage to the chainsaw if it accidentally cuts into the ground or hits a stone, but chainsaws are fairly robust and relatively easy and cheap to repair, much more so than very expensive integral circular saws such as the Bracke felling head.This type of integral chainsaw cutting bar is often mounted on small-medium sized timber grabs and marketed as bioenergy felling heads; the Gierkink GMT 035 (www.gierkink.nl) is one of several available. Circular saw: an integral circular saw is also very susceptible to wear and damage, however the advantages are that is cuts easily and quickly, gives a good clean cut, and can cut through large diameter timber. This type of circular saw cutting mechanism is also very good at cutting multi-stemmed shrubs or trees such as coppice stools, and can be found in the Bracke Forest C16.c (www.brackeforest.com).

Hydraulic tree shears: a third cutting mechanism uses hydraulically-powered blades to slice through

trees instead of cutting with a saw. The diameter of timber which they can cut through depends on the model being used, for example the Westtech Woodcracker C550 can cut through trees up to 50cm in diameter. If the blade is kept sharp, there is no substantial damage to the tree stump in com-parison with a chainsaw. The big advantage with tree shears is the lack of moving parts, making their maintenance and susceptibility to damage much smaller. For example if the shears cut into

the ground, it will not cause any major damage to the blades. With this type of tree shears, the blade cuts against a kind of anvil, and so this cutting mechanism is less suitable for harvesting multi-stemmed trees and shrubs. This is because the branches are bunched together which causes damage, such as splitting to the stump or stool. With older coppice stools or larger multi-stemmed trees, it may be necessary to cut the stems higher than actually desired because there also needs to be room for this large tree shear felling head to get in between the stems. In this situation, the base of the stems may need to be cut back to the stool with a chainsaw.

Figure 5. Felling head with hydraulic tree shears, a Westtech Woodcracker C350

Figure 4. Felling head with integral circular saw, the Bracke Forest C16.c

© O

RG

AN

IC R

ESE

AR

CH

CE

NTR

E

© A

BC

EC

O2


Stabilisation functionSome felling heads are able to hold the felled tree upright and can then lay it down where desired. This stabilisation function is only found in the larger felling heads which are strong enough to have full control over the direction of the felled tree, such as the Westtech Woodcracker C550. In forestry work it is often not necessary to have this level of control, but with hedgerow work it can be very useful, especially where space is limited so that the tree can be laid down in another location some distance away. Additionally when a tree is laid down in a controlled manner there are fewer broken branches to clear up from the fields as compared to when trees are felled.

Accumulator functionAll felling heads have at least one pair of arms to hold the felled tree, however the larger felling heads such as the Westtech Woodcracker C550 or the Bracke Forest C16.c are generally equipped with at least two pairs of arms which provide the accumulator or feller-buncher function, enabling a single felled stem to be held while grabbing and holding more stems to be cut, before the whole bundle of hedgerow material is set down. In some cases this mechanism can be a real time saving device, particularly when the trees need to be set down in a different location from where they were felled. However the various sets of arms take time to open and close, so that sometimes it is faster to just move the trees one by one.

3.1.3. FOREST HARVESTERIn forestry even more specialist machines are available and used, which for example can fell and manoeuvre whole trees, remove their side branches and cut the trunk into pre-programmed specific lengths. However most of these machines are not sufficiently mobile to harvest hedgerows at a landscape scale, and are very expensive to hire or buy. In addition hedgerow trees are generally not as straight and uniform as in woodlands, plus they would not deal well with small multi-stemmed shrubs, so that is impractical to use these machines in the context of harvesting or coppicing hedgerows.

3.2. STOCKPILING AND TRANSPORTING THE HEDGEROW MATERIAL

Transporting the harvested whole-tree hedgerow material before it is chipped is best avoided because it is a very high volume material when compared to the volume of woodchips it produces. There are some machines available which can compress or bale up the harvested hedgerow material to transport it before chipping it, but the processing costs will definitely rise if this addition-al process step is carried out.A traditional timber lorry is designed to carry cordwood; if it is used to transport brushwood or whole-tree hedgerow material it would be very time consuming to load all the material on. A machine called a press-collector has been designed to solve this problem however; it has folding sides which compress the branch material down after it has been stacked on. The press-collectors which are currently available are unfortunately too wide to operate on public roads, as they have been devel-oped for use in forestry situations. New bespoke made machines could however be adapted.A felling head with a stabilisation function can also carry whole trees across a (very) short distance to another location. However, this results in sig-nificant losses in harvesting efficiency and hence cost increases as a result. Whenever possible the brushwood or whole-tree hedgerow material should first be allowed to dry before it is chipped. This is discussed in the section on Storage and drying.

3.3. PROCESSING THE HEDGEROW MATERIAL BY CHIPPING

There are different methods and different ma-chines which can be used for processing branches, trees and whole-tree hedgerow material, each re-sulting in a different type and quality of woodchip. This guide looks at shredding and chipping options, but does not cover processing timber into logs for firewood or any other timber products such as fence posts or planks. It is very important to ensure that the woodchip quality and the requirements of the wood chip boiler are matched to each other.


In the selection of an appropriate chipping machine, there are a number of key considerations:• method of processing – shredding, chipping with

a disc chipper, chipping with a drum chipper• manner of woodchip ejection• size of timber the chipper can process - intake

width and dimensions• intake mechanism design – chains, rollers or

moving intake table

3.3.1. SHREDDERA shredder tears and splits the branches length-wise. This produces fibrous long strips instead of chunks or chips. This processing method is not usually recommended for small-scale woodfuel boilers, but is more appropriate when the shredded timber is going to be composted.

3.3.2. DISC CHIPPER - MANUALLY FEDMost manually fed chippers are disc chippers. These are mostly smaller chippers usually used by landscaping contractors which can take timber up to approximately 20cm diameter. The cutting blades are mounted on a rotating disc.

3.3.3. DRUM CHIPPER – CRANE FEDIn this type of chipper the blades are axially mounted on the shaft on a large rotating drum.

As a result, more force can be exerted and larger diameter timber can be chipped and at a higher rate.Aside from choosing a particular type of chipper, various additional features are available which need to be considered including:

3.3.4. LOADING CRANEWhen you have larger diameter timber to chip, and it cannot be lifted, moved or fed into the chipper easily by hand, then you need a crane-fed chipper. What is important here is that the crane has sufficient reach so that it can lift the trees from the field, over the hedge and feed them straight into the chipper that is working from the road.

3.3.5. INTEGRAL WOODCHIP HOPPERWhen chipping it is generally necessary to have a second tractor with a trailer or container, such as a hooklift bin, parked either behind or next to the chipper in order to collect the woodchips. This requires a second tractor driver, unless the chipper operator moves the woodchip trailer when neces-sary. There are however some models of chippers which have their own integral woodchip hopper mounted on the same chassis as the chipper. These usually operate using a high tip function, which tips the woodchips into a larger trailer or hooklift bin.An integral woodchip hopper is a particularly valuable feature when there is little space for

Figure 7. Hedgerow harvesting machine train working on a hedge in Bocholt, East Belgium. Note the loading crane on the chipper and the 13m³ integral woodchip hopper.

© A

BC

EC

O2

Figure 6. Drum chipper: Ufkes Greentec VC 942-13

© A

BC

EC

O2


a second tractor and trailer, or if there is only a small amount of timber in any one location. The time taken for the hopper to empty needs to be considered, as this is dead chipping time, so for large piles of wood it is more efficient to chip directly into a trailer or hooklift bin rather than use the woodchip hopper.

3.4. TRANSPORTCareful thought needs to be given to transporting woodchip because the transport costs can quickly rise to a quarter of the total cost of harvesting and processing hedgerow material. Due to the bulky, high volume nature of woodchips (ie their low spe-cific gravity), they need to be transported in large 40m³ containers or hooklift bins, 60m³ grain lorries or 90m³ walking floor lorries in order to minimise transport costs.

3.5. STORAGE AND DRYINGWoodchip should ideally be dry before it can be used as woodfuel. When hedgerow material is harvested during the winter and chipped shortly afterwards when it is green, the woodchip moisture content is 50% on average. In order to use wood-chip as a fuel for heating, it needs to be dried down to an average moisture content of 20-30%. This is usually done by allowing the woodchip to dry naturally, but there are other options.

Depending on the space available, the harvested whole-tree hedgerow material can either be stored unchipped out in the field to air dry, or if chipped first, it can be stored outside on an area of concrete and covered with a breathable geotextile cover such as Toptex®, or inside in a well-ventilated barn, where it can be left to dry naturally through self-heating or actively dried through blowing ambient or heated air through it.

3.5.1. NATURAL DRYING THROUGH SELF-HEATINGThis method of natural drying through self-heating is currently the most commonly used method to dry woodchip. To use this method the woodchip should be piled up on an area of concrete, either under cover in a barn or covered with a breathable geotextile cover such as Toptex®. After a couple of days, the woodchip starts heating up and the temperature in the woodchip pile can eventually get up to 65°C. The heat generated within the pile

moves upwards creating convection currents and setting up a natural drying process whereby the moisture moves up through the pile and evaporates from the surface. The water vapour exits from the top of the pile where it condenses when it comes into contact with the colder air. In order to keep this condensation to a minimum it is important to keep the surface area of the top of the pile as small as possible. With this drying method it is therefore very important that the woodchip pile has a conical shape.The conical shape means that the surface area to volume ratio of the heap is as small as possible, so that when the woodchip is dried outside under a Toptex® cover the surface area which is exposed

Figure 8. The drum chipper is hidden behind the green hooklift bin, but the 13m³ integral woodchip hopper is being emptied into the 40m³ tractor-towed hooklift bin.

© A

BC

EC

O2

Figure 9. Natural drying of woodchip through self-heating.

© A

BC

EC

O2


to the rain is also minimised. The steep sides also ensure that the rain runs down the cover and off the heap rather than seeping through it. Furthermore, it is advised not to turn the woodchip pile as this will encourage composting.This natural drying method through self-heating works relatively well. If everything goes well , an average moisture content of 30% or less can be achieved in three months, but it can also take more than six months if it is wet or humid. It does however usually result in relatively high dry matter losses. When the woodchip moisture content is over 30%, there is on average a 3-5% loss of dry matter per month as a result of the decomposition which generates the heat. Over the whole 3-6 month drying process dry matter losses of 20% are common, which equates to a 20% loss in calorific value of the woodchip.Other disadvantages of this drying method are that the moisture content is generally not homogenous and is often actually quite variable throughout the woodchip pile. Mould can also form on the damp woodchip producing fungal spores which can have negative health effects if breathed in. If mould does develop, it is recommended that a protective dust mask be worn when loading or moving the woodchips.

3.5.2. FORCED OR ACTIVE DRYINGFresh woodchip can also be dried by forced or active drying. This can be done using ventilation ducts or grills in the floor or using perforated domes, like are used to dry and ventilate grain and

potatoes. Ambient air or heated air can be blown through the woodchip to dry it. On a small scale, forced drying can be done in hooklift bins with a perforated floor through which the drying air is blown.In the Bocholt hedgerow harvesting trial area, trials have been carried out where woodchips have been force-dried using the residual heat from a nearby biogas or anaerobic digestion plant. Figure 10 shows the experimental woodchip drying design: an open air concrete-walled bay with a central air duct, through which the residual heat is blown. Here the woodchips were completely dry after five days, with a moisture content of less than 20%. Using this drying process there was no dry matter loss and no mould had developed. Unfortunately no relevant data was available on the electricity consumption of the fans. This was because the fans operated on the basis of the quantity of heat which the anaerobic digester needed to dissipate, rather than the relatively small amount of heat that the woodchips required to be dried. The disadvantage of this experimental woodchip drying design was the length of time required to fill and empty the drying bay in propor-tion to the required drying time. In the future, it is hoped that trials can be carried out with a conveyor belt fed dryer, which should enable woodchip drying to be done much more efficiently.Further trials have recently been carried out into the forced drying of woodchips in a hooklift bin used as a drying container connected to a small anaerobic digester. The hooklift bin has a double floor and air supply vents have been built into the rear doors. This small anaerobic digester produces a lot less surplus heat, so drying is slower than when connected to the large-scale anaerobic digestion plant. The drying container can however also be connected to large-scale biogas plants or other sources of hot air, and several containers of woodchip could be connected to a large plant simultaneously. The big advantage of the hooklift bin system is that it provides a complete hedge to customer system. Hedgerow material can be chipped or tipped directly into a fieldside hooklift bin, which can then be towed straight to a drying installation such as a local anaerobic digestion plant, where it

Figure 10. Woodchip being force dried in a hooklift bin container (left), and in a concrete walled bay with a central air duct, (right)

© A

BC

EC

O2


can be connected up and left until the woodchips are dry, and then taken directly to the customer, where it can be tipped into a woodchip store. The hooklift bin drying system therefore minimises the handling of the woodchips with regards to the loading and emptying of the drying bays, which in turn significantly reduces the drying cost and

therefore the overall production costs of hedgerow woodchip. The one disadvantage of this drying system is that the hooklift bin can’t be used for any other purpose, such as to transport the woodchip from the field to the storage site, whilst it is being used as a drying container, so it may be necessary to buy several of them. The investment in a woodchip drying system needs to weigh up the loss of dry matter through natural drying by self-heating against the amount of work required to load and unload the woodchip in order to actively dry it. Another challenge is to monitor the moisture content of the pile as the woodchip dries. To date, only devices which continuously monitor the temperature of the woodchip have been found, but not those which will continuously monitor the moisture content. Certainly when drying woodchip quickly (and expensively) it is very important to monitor the moisture content and stop drying as soon as the woodchip is at the right moisture content. In addition to this, Inagro an agricultural research organisation in West Flanders, has also carried out research into drying woodchip, They have evaluated three different woodchip drying methods: • The first method looked at naturally drying

woodchip through self-heating outside under a breathable geotextile cover (Toptex®) in a trench silo or open air concrete walled bay.

• The second method was also naturally drying woodchip through self-heating, but in a well-ven-tilated barn with a concrete floor.

Figure 11. Inagro’s woodchip drying trials: Natural drying in a well-ventilated barn (above); Natural drying outside under Toptex® (middle) and Forced drying in a container with unheated ambient air (under).

© IN

AG

RO

© IN

AG

RO

© IN

AG

RO

Proefopzet geforceerd drogen in droogcontainer.

© A

BC

EC

O2


• The third method was forced drying of woodchip in a container with unheated ambient air being blown through it.

Each week the average moisture content of the woodchip was measured for each of the drying methods. The weekly sampling results found that the rate of drying for the three methods was not significantly different (see Figure 12 below). This

showed that woodchip does not dry any more quickly when actively ventilated with unheated ambient air. The graph below shows the course of the woodchip drying process on the basis of the average moisture content results of the three tested drying methods.Forced drying or active ventilation with ambient (outside) air does help to limit the loss of dry matter. With active ventilation there was virtually no heating up of the woodchip. As a result, the dry matter losses were 3-11% lower than with the other drying methods (see Table 1 below).

From an energy expenditure perspective, drying woodchip in a barn (with or without forced ventilation) is the preferred method. However when viewed in financial terms, it is noted that the advantageous lower dry matter losses are offset in part by the higher investment costs required to dry woodchip in a barn (whether with or without ventilation). Based on the current sale price for woodchips (€85/tonne or £61.20/tonne), the finan-cial gain of drying woodchip in a barn is limited to ± €3/tonne or £2.16/tonne of dry wood chips.Furthermore, it was not clear whether the wood-chips which were force dried in a container with active ventilation had a more uniform moisture content.Further information on these woodchip drying trials and the guidance and results that came out of them can be found in the Results section of the TWECOM website: www.twecom.eu An important consideration is that in order to dry woodchip in a barn, it needs to be a well-ventilated barn with open sides or ends. It is very important that the wind can blow through the barn so that the moisture which exits from the top of the woodchip pile can evaporate.

3.5.3. AIR-DRYING IN THE FIELD (BEFORE CHIPPING):If you have enough space, you can leave the har-vested whole-tree hedgerow material in the field to dry for a few months before chipping. Depending on the diameter of the timber and the species of wood this may give very good results. Using this method, you can produce dry woodchip straight from the field without any risk of mould or fungi forming. Renting part of a field from the farmer for a few months is cheaper than renting a concrete yard or barn. This method was also trialled in the UK by The Organic Research Centre.Chipping dry hedgerow material or timber may however result in higher fuel use and wear and tear on the chipper. This may especially be the case when chipping hardwoods such as oak and acacia, for which this technique may not advisable. If the wood is left to dry for too long, the woodchip quality may be disappointing as the timber may shatter and break rather than be cut into nice clean good quality woodchip.Further information on these hedgerow harvesting

0

50

302010

40

90807060

100

23 /02 5 /03 13/03 19/03 30/03 7/04 15/04 20/04 12/05

% D

roge

sto

f

datum staalname

Evolutie droogproces houtsnippers

Figure 12: This graph represents the woodchip drying process over time, and shows the average rate of drying of the woodchip for the three drying methods. Percentage dry matter is shown on the y axis and the woodchip moisture content sampling dates are shown on the x axis.

Table 1. This table summarises the advantages and disadvantages of the three woodchip drying methods trialled by Inagro.

Breathable TOPTEX® cover

In a barn In a container with a fan

ADVANTAGES Low investment costs Low dry matter losses (±12%)

Low dry matter losses (±9%)Clearly less fungal spores and mould

DISADVANTAGES High dry matter losses (±20%)Lots of fungal spores and mould

High investment costs (3.5x more than TOPTEX®)Lots of fungal spores and mould

High investment costs (4x more than TOPTEX®)


trials and the guidance and full results that came out of them can be found on the TWECOM page of The Organic Research Centre website: http://tinyurl.com/TWECOM

3.6. FURTHER PROCESSING OF HEDGEROW WOODCHIP

3.6.1. SCREENING In order to obtain uniform woodchip, it may be necessary or desirable to sieve or screen the woodchip. This is best done when the woodchips are dried, so that any fines or soil do not stick to

the woodchip but are removed. It is better to keep the woodchip clean and avoid getting any soil on them by making sure the hedgerow material stays as clean as possible before it is chipped and keeping the yard clean and tidy. It is also important to choose the right chipper and to keep the blades nice and sharp, so that the size of the woodchip is optimised and the proportion of fines and long shards is minimised. Three different

types of sieve or screen are available on the market: drum screen, shaker or vibrating screens and star screens. agrobeheercentrum Eco² in Leuven, Belgium has carried out trials screening hedgerow woodchip with a shaker or vibrating screen. This had two screens with 20mm and 40mm diameter perfo-rations, one above the other. In this trial 118m³ of woodchips was screened at a cost of €2.75/m³ or €8.25/tonne (£1.98/m³ or £5.94/tonne), see Table 2 below. It is possible that this screening process could be further optimised so that it is more efficient and cost-effective.

Table 2. Woodchip screening trial results. Hedgerow woodchip particle size distribution after screening.

Particle size m³ percentage (%)

Oversize >50mm 3 2.5

Nice woodchip 50mm-20mm 80 68.0

Fines <20mm 35 29.5

Total 118 100.0

Figure 13. Woodchip screening trial in Bocholt using a shaker screen.

© A

BC

EC

O2


4. TWECOM HEDGEROW HARVESTING MACHINERY TRIALS

4.1. CASE STUDY: ROADSIDE HEDGEROW TREE HARVESTING IN BOCHOLT

One of the TWECOM project’s hedgerow harvesting trial areas was the Bocholt district in the North Limburg province of Belgium. In this area there are more than 70km of local authority owned roadside hedgerows; these hedges are now more like lines of mature trees, consisting primarily of 40-60 year old oak trees, which form avenues along the roads. For several decades the only kind of maintenance has been the high pruning of the lower branches in order to keep the roads clear.Now the objective is to bring a large proportion of the hedgerow network in the Bocholt pilot area into coppice management, harvesting 5km of hedges annually on a rotation of approximately 10 years. A landscape-scale hedgerow vision plan has been produced for this pilot area by Regionaal

Landschap Lage Kempen (RLLK), a regional land-scape organisation in Flanders, and is supported by all the relevant stakeholders. As part of this trial, all the necessary felling licences and permis-sions have been applied for at a landscape scale.

4.1.1. LANDSCAPE-SCALE HEDGEROW RESTORATIONIt is often recommended that for each individual hedge no more than one third of the total length is harvested each year, so that there is no significant impact on the biodiversity or the landscape. As most hedges aren’t that long, it doesn’t pay to hire in a machine to harvest a single section of hedge. If however hedges are managed on a landscape scale, then it becomes feasible to harvest several different sections of hedgerow at once, as part of the same contract.Hedgerow harvesting can be further optimised by matching up the volume of timber to be harvested

Figure 14. A hedge-rich landscape in the Bocholt district of Limburg for which a landscape-scale hedgerow vision plan has been produced by Regionaal Land-schap Lage Kempen (RLLK).

© B

EN

NY

VAN

GA

NSE

WIN

KE

L


from hedgerow lengths to the capacity of the woodchip hopper on the chipper. Timber from approximately 70m of hedgerow just about fills the 13m³ hopper. When three or four similar 70m sections of hedge are harvested in the same area, they are likely to fill the 40m³ hooklift bin. These hedgerow sections need to be within 1km of the parked hooklift bin to minimise the chipper oper-ators’ driving time. For hedges further afield, the hooklift bin needs to be moved.

4.1.2. THE MACHINERY USED IN THE BOCHOLT TRIALThe hedgerow harvesting trials in Bocholt district were of a completely different scale and nature to those carried out in the UK. This trial did not so much involve hedgerow coppicing work, but mature tree felling work, hence heavy large-scale machinery was used. The machinery selected for harvesting the roadside hedgerows and processing and transporting the hedgerow material in Bocholt district included:

Excavator: A 16-tonne wheeled excavator was used because all of the hedges to be harvested were accessible from the road, but scattered across the district. It was therefore important that the excava-

tor could drive from one hedge to another under its own steam, rather than having to be transported. A relatively large and heavy excavator was needed because most of the hedges were over-mature and had formed lines of large mature trees, which were approximately 4m apart, 6-8m high and 40-60cm in diameter, and so the excavator had to be able to handle large trees without tipping over.

Felling head: A Westtech Woodcracker C350 felling head with hydraulic tree shears was used. These tree shears can cut trees up to a diameter of 35cm, and are particularly suited for felling large single-stemmed trees, which are prevalent in the hedges of Bocholt. It also has a stabiliser function so that the trees can be held upright once felled and laid down where needed.This combination of wheeled excavator and tree shears felling head are particularly suitable for managing over-mature hedgerows, where large trees need to be felled or harvested. At the start of the next coppice cycle, which is expected to be approximately ten to fifteen years, it is likely that a smaller and lighter excavator with a different type of felling head will be more appropriate to harvest the smaller diameter, multi-stemmed regrowth from the tree stumps.

Chipper: An Ufkes Greentec 942/13 crane-fed drum chipper was used which produces very good quality woodchip. This chipper has side intake rollers, which means that trees with protruding branches or bushy hedgerow material can be fed into the chipper more easily. This model with only the very basic intake tray (without chains or a moving intake table) was chosen because if the intake mechanism breaks it could cause enormous damage to the chipper or the surrounding area as a result of the metal shrapnel which would be pro-

duced. The chipper is also equipped with a loading crane and a 13m3 integral woodchip hopper which operates using a hydraulic high tip mechanism

Figure 15. A 16 tonne wheeled excavator with Westtech Woodcracker C350 tree shears felling head

© A

BC

EC

O2

Figure 17. An Ufkes Greentec VC 942-13 crane-fed drum chipper with integral woodchip hopper

© A

BC

EC

O2


Through the hedgerow harvesting trials in Bocholt, it has been found that it works best when the wheeled excavator with felling head arrives on site first to fell and lay down or stack the trees. Several hours or days later the chipper is brought to site, and with its crane cleans up and chips all of the harvested hedgerow material. The rate of felling and chipping is variable and depends on the hedge, which is why it is preferable if the harvesting and chipping machines are not both working on the same hedge at the same time.Transporting the woodchip: The woodchip is transported using a tractor and a hooklift bin system mounted on a trailer chassis. The hooklift bin can be set down and left near to where the hedges are being harvested and chipped, so the tractor driver doesn’t need to stay with it. The chipper chips into its integral hopper, which is then intermittently emptied into the lowered hooklift bin. The woodchip is generally stockpiled and stored on an area of concrete (often an old silage clamp) on a local farm, and so the woodchip usually only has to be transported 5km at the most.

Figure 18. Hooklift bin container system towed behind a tractor

© A

BC

EC

O2

Drying the woodchip: The woodchip was dried naturally through self-heating by stockpiling it in a conically-shaped heap on an area of concrete. The hedgerow trees were harvested in mid-March 2015 and chipped pretty much straight away; the wood-chip was left uncovered due to the dry weather. At the end of April the wet layer of woodchip was removed from the top of the heap (see Figure 19 below) and taken to be actively dried in a hooklift bin connected to a small biogas installation. This wet woodchip was dried in the hooklift bin from 55% down to 20% moisture content in one week.

After two months, so by May the rest of the wood-chip pile was sufficiently well dry at 25% and the heap was covered with a breathable Toptex cover.

4.1.3. ANALYSIS OF THE HEDGEROW HARVESTING TRIAL RESULTS

The harvested hedges in Bocholt district yielded approximately 60kg of fresh timber per linear metre of hedge. The hedgerow harvesting costs for the Bocholt trials, which included felling, chipping and transport to the woodchip store totalled ap-proximately €3/m or £2.16/m (see Table 4 below). As a result of harvesting 2km of hedgerow in 2015, 120 tonnes of fresh woodchip with a moisture content of 50% was produced. This theoretically equates to 86.3 tonnes at 30% moisture content, however if a 20% dry matter loss from natural drying is taken into account, this results in 69 tonnes of dry woodchip. At a market value of €85/tonne, this represents a gross income from hedge-row woodchip production of €2.86/m or £2.05/m, excluding the costs of woodchip storage and drying and transport to the customer.

Figure 19. This diagram represents the distribution of moisture content in the pile of woodchip on 25-04-15. (Vocht means moisture content)

55% vocht

29% vocht

20% vocht

Tabel 3 Time taken to harvest, chip and transport 120 tonnes of hedgerow material

43.0 hours chipping 2.79 tonne/hour chipping

36.5 hours harvesting 3.29 tonne/hour harvesting

14.5 hours transporting 8.28 tonne/hour transporting

The production cost (felling, chipping and trans-porting) of fresh hedgerow woodchip was approxi-mately €55/tonne or £39.60/tonne. This production cost increases to €77/tonne or £55.44/tonne when the woodchip is dried to 30% moisture content, not taking into account any dry matter losses


However, the costs for storage, drying and transport of the woodchip to the customer, and po-tentially the cost of screening, must be calculated and included before the total and final hedgerow woodchip production cost is known. At the moment it is not possible to carry out a full cost analysis, but the first estimates are that €20-25/tonne or £14.40-18.00/tonne appears realistic for drying and transporting the woodchip.The woodchip production cost includes harvesting, chipping and transport costs.Euros have been converted to Pound sterling using the mid-market exchange rate of €1 = £0.72 from 27-10-2015 taken from http://www.xe.com/currencyconverter

4.2. CASE STUDY: HARVESTING TIMBER FROM LANDSCAPE ELEMENTS IN LIMBURG PROVINCE

In addition to the hedgerow harvesting trials in Bocholt district, other timber harvesting operations have been carried out in other parts of the Limburg province. This table presents the production costs of harvesting timber from those sites, including embankments in Genk and Tongeren and a sunken holloway in Velm.

Table 4. Hedgerow woodchip yield and production costs in Bocholt from trials in 2014 and 2015.

Hedgerow length (m) Fresh woodchip production (tonne)

Woodchip production (kg/m) Woodchip production cost (€/m & £/m)

Theoretical gross income (€/m & £/m)

Bocholt hedges 2014 1700 99.0 58.2 3.30 & 2.38 2.64 & 1.90

Bocholt hedges 2015 2050 120.9 59.0 3.08 & 2.22 2.86 &2.05

Table 5. Breakdown of hedgerow woodchip production costs in Euros in Bocholt from trials in 2014 and 2015Total production cost (€/tonne) Harvesting cost

(€/tonne)Chipping cost (€/tonne) Transport cost

(€/tonne)

Bocholt hedges 2014 56.66 21.91 24.14 10.61

Bocholt hedges 2015 52.21 12.62 32.66 6.94

Table 6. Breakdown of hedgerow woodchip production costs in Pound sterling in Bocholt from trials in 2014 and 2015Total production cost (£/tonne) Harvesting cost

(£/tonne)Chipping cost (£/tonne) Transport cost

(£/tonne)

Bocholt hedges 2014 40.80 15.78 17.38 7.64

Bocholt hedges 2015 37.59 9.09 23.52 5.00

Table 7. Breakdown of timber harvesting yield in Limburg Province and production costs in EurosWoodchip yield Woodchip production cost

Hedgerow length (m)

Fresh woodchip yield (tonne)

Woodchip yield(kg/m)

Total woodchip production cost(€/m)

Total woodchip production cost(€/tonne)

Harvesting cost (€/tonne)

Chipping cost (€/tonne)

Transport cost(€/tonne)

Transport cost (% of total production cost)

Felling Broekkantstraat poplars in Peer 40 27.9 698.0 57.30 82.10 24.06 34.25 23.79 29.0

Felling Broekstraat avenue of trees in Peer 318 22.0 69.1 4.65 67.28 16.69 41.95 8.63 12.8

Coppicing work on a railway embankment in Genk 1147 170.4 148.5 13.58 91.41 26.39 39.00 26.02 28.5

Hedgerow harvesting in Bocholt 2014 1700 99.0 58.2 3.79 65.15 25.19 27.76 12.20 18.7

Hedgerow harvesting in Bocholt 2015 2050 120.9 59.0 3.54 60.04 14.51 37.56 7.98 13.3

Hedgerow harvesting in Velm 299 50.4 168.6 19.28 106.14 38.99 47.86 19.29 18.2

Felling and clearing work in Helchterhoef parish 0 459.4 - - 64.76 18.81 27.08 18.87 29.1

Harvesting a plantation 2 hectare 104.5 - - 59.21 18.50 40.70 - -

Riverbank coppicing in Houthalen 720 212.5 295.2 14.67 48.81 10.46 28.98 9.37 19.2

Hedgerow coppicing in Tongeren 1075 314.0 292.1 24.60 83.36 28.03 37.31 18.03 21.6

Total 7349 1581.1

Average 178.9 17.7 72.8 22.2 36.2 16.0 21.2


4.3. CASE STUDY: DYKE-SIDE ALDER ROW HARVESTING IN WEST FLANDERS

West Flanders is a very flat and intensively cul-tivated area of polder with few hedges or woods, described here as landscape elements. There are however lots of rows of the native black or common alder trees (Alnus glutinosa) which are growing along the water courses. During the development of a land consolidation plan in Lo-Reninge and Woesten districts eight years ago, a lot of consideration was given to the management and maintenance of existing small landscape elements, as well as to the planting and management of new ones such as the alder rows. At this time, about 5.5km of new alder rows were planted alongside drainage ditches and field margins across the area. These trees are now approximately 8 years old, 1.5m apart, 8m high and 12-15cm in diameter. As the alder trees had started to shade farmers’ crops, a management regime was required to cut them back to prevent shading the adjacent fields. The plan was to introduce a coppice rotation management system and harvest these rows of alder trees on an eight to twelve year cycle. Once these single-stemmed trees have been felled in the initial round of management, they will grow back as multi-stemmed alder coppice.

20151,2 km

20191,3 km

2021

1,5 km

2017

1,5 km

In order to seek the most cost-effective, and in the future possibly profitable, management of these alder rows, Inagro were asked to work with the different stakeholders in the area. The districtsof Lo-Reninge and Vleteren, the Zuidijzerpolder and the regional landscape Ijzer en Polder were all involved as owners of alder rows. To make this

management of the alder rows work and be as profitable as posssible, a market for this locally harvested timber was required. Various farmers in the region have woodfuel boilers that burn wood-chip to heat their greenhouses and pig and poultry barns, and they were also involved in this project as potential woodchip customers.

Figure 20. An alder row in the land redistribution area of Lo-Reninge

© IN

AG

RO

Until recently, these alder rows have been managed in a very disorganised and disjointed manner. If farmers wanted, they could harvest the rows of trees adjoining their property and take the wood for their own personal use. The drawbacks of this system were that there was no way of knowing when certain strips were going to be harvested or whether the work would be carried out to a good standard. For those alder rows where the person responsible for their management couldn’t be found, the felling work was done using social em-ployment In these instances, the management was very expensive and no consideration was given to the valorization or sale of the wood to reduce the net management costs.It was therefore decided that a concrete manage-ment plan would be produced and a co-ordinated and efficient approach taken to management of the alder rows. Every two years approximately 30% of the alder rows will be harvested, and after eight years the coppice harvesting cycle will begin again. This system ensures the sustainable long-term management of the alder rows.

This management system has several advantages:• A concrete management plan allows for better

management: this makes it clear when each


alder row is ready to harvest and when it will be harvested. Management is therefore easier to follow.

• Phased harvesting: this avoids significant land-scape change in any one area

• One contractor: this makes it easier to manage the harvesting work

• Professional management: the quality of the alder row management work is guaranteed and the process is standardised

• Efficient use of woody biomass in high-efficiency woodfuel boilers

• Local sale and use of the biomass: this limits transport costs and fuel use

• Cost effective: drying the woodchip allows it to be sold at the market price for dry woodchip (up to 3x higher than market price of fresh woodchip)

• Good woodchip quality: this is ensured by moni-toring the whole process

4.3.1. ALDER ROW HARVESTING METHODOLOGY AND IMPLEMENTATION

For the harvesting of the alder rows, Inagro worked with a local contractor working on behalf of Agro|aanneming. The alder trees were harvested using excavator-mounted hydraulic tree shears, and cut approximately 30cm from the ground. The whole trees were chipped with a large drum chipper.

Through drying the woodchip produced, it was possible to reduce the net management cost of the alder rows. This is because the sale price of dry

woodchip is three times higher than that of fresh woodchip. The woodchip was dried in a grain store using a forced ventilation system, ie. fans. After about three months the woodchip was dry enough (approx. 30%) to be sold to a local farmer with a woodfuel boiler at €85/tonne or £61.20/tonne (dry woodchip market price in Flanders in summer 2015 based on 30% moisture content).

4.3.2. COST-BENEFIT ANALYSISIn both 2014 and 2015, the alder row harvesting cost per linear metre was calculated at approx-imately €2.68/m or £1.93/m. The value of the harvested wood can of course be offset against these management costs; in Flanders in summer

2015 this was about €85/tonne or £61.20/tonne (based on 30% moisture content). As a result of harvesting a total of 1200m of alder row, over 50 tonnes of fresh woodchip was produced, which equates to 41.7kg of fresh wood per metre. This equates to more than 33 tonnes of dry wood (30%) having been harvested, resulting in a gross income of €2.34/m or £1.68/m.In addition, it is necessary to take into account the additional costs for drying and transporting the woodchip. Respectively these costs are €9.03/tonne or £6.50/tonne for drying the woodchip and €9.27/tonne or £6.67/tonne for transporting the woodchip. The income received from the sale of dried woodchip is more than sufficient to cover the drying and transport costs and will even partially cover the management costs. The total cost of the alder row management work is reduced by about

Figure 21. Whole-tree alder row material being chipped using a crane-fed drum chipper.

© IN

AG

RO

The resultant woodchip being force dried with fans in a grain store container.

© IN

AG

RO


75% through the sale of dried woodchip. If you compare the residual or net cost of the alder row management work (the outstanding 25%) to the price that was formerly paid for this management work, the result is that co-ordinated management is achieved for a 65% reduction in price.

4.3.3. LOCAL USE OF WOOD HARVESTED FROM THE LANDSCAPE

The 33 tonnes of dried woodchip harvested from the alder rows in 2015 was sold and delivered to an interested local farmer where it was burned in high-efficiency biomass boiler installations for heating livestock sheds and greenhouses. Woodchip harvested from 1.5km of alder row is ap-proximately equivalent to 15,000 litres of kerosene heating oil. In the immediate vicinity of the alder rows there are two pig farmers, a carnation grower and a veal rearing unit, all of whom heat their barns and greenhouses with woodchips.

4.3.4. FUTURE PROSPECTS IN THE LONGER TERMAlthough a significant reduction in the alder row management costs was achieved, the districts involved, the Zuidijzerpolder and the regional landscape of Ijzer en Polder, still need to make a limited financial contribution to the management of the alder rows. Inagro believes that in the near future it is possible that the maintenance of the alder rows will become cost-neutral.On the one hand, Inagro strives to seek more cost-effective woodchip storage and drying methods. On the other hand Inagro also wants to increase woodchip yield per linear metre of alder row, by increasing the length of the coppice rota-tion cycle, from 8 years to perhaps 12 years.

We can also expect a higher productivity of the alder hedgerows in their subsequent coppice rotations. Research has suggested that the yield from the first coppice harvest is generally less productive than from subsequent coppice rotations, by which time the alder should grow bigger and faster due to the well-established root system. A further increase in the average sale price of quality woodchip in the future, for example to €100/tonne or £72/tonne (as in Brittany, France) would ensure that hedgerow management becomes cost-ef-

fective or cost-neutral and possibly marginally profitable.All involved parties were very enthusiastic about this alder hedgerow management system and would like to continue to develop and optimise this management in the future.Further information on these alder row harvesting and woodchip storage and drying trials, and the results and recommendations that came out of them can be found on the TWECOM website: www.twecom.eu


Figure 23. Recently coppiced alder row in West Flanders

© IN

AG

RO

5. POST-HARVEST HEDGEROW CAREIn a cyclical coppice rotation management system where each hedgerow is harvested approximately every ten years, it is also necessary to carry out certain maintenance tasks such as cutting back roadside branches in the intervening period between coppicing. This hedgerow maintenance is necessary to maintain a healthy and vigorous hedge, but also to prevent any problems arising with neighbouring landowners.

5.1. GAPPING UP HEDGEROWSWhere there are gaps in the harvested hedgerows of more than 4 metres, they will be planted or gapped up with coppice species at 0.5m spacing. This gapping up can be done in the autumn imme-diately after harvesting or coppicing.Once harvested tree stumps or coppice stools have had two growing seasons to grow back, the extent and vigour of the coppice regrowth will be checked. Particularly where large over-mature hedgerow trees have been coppiced, it is common for these tree stumps not to re-grow or for there to be very little coppice regrowth. In this situation, if there are no other trees or shrubs adjacent which can grow up and create a nice thick hedge which

will produce a good woodfuel harvest, then it will be necessary to gap up these sections of hedge. Research is needed into what methods can be used to increase the survival rate of the newly planted trees and shrubs.

5.2. HEDGEROW TREE DEVELOPMENTFrom those hedgerow trees which are not coppiced, it might be possible to produce quality wood. Timber stems need to meet a large number of criteria in order to be considered as high quality wood: a straight, branch-free trunk without damage is usually required. High quality stems like this don’t automatically grow in a hedgerow situation. The abundantly available light stimulates side branch growth in all directions; quite different from in a woodland environment. Good formative pruning is therefore needed in the first few years after planting new hedgerow trees, and should be done very judiciously. Specialist pruning courses which cover tree pruning and formative pruning are available at various horticultural and forestry schools, including Inverde in Belgium and the RHS in the UK.


6. CONCLUSIONSThe TWECOM Project provided the opportunity to thoroughly research the management, harvest and ongoing maintenance of hedgerows for woodfuel energy, and to look in depth at the specific chal-lenges that this entails. Although many research papers have been written on the harvesting of wood for energy, they rarely go into any depth regarding the management of hedgerows for woodfuel. In par-ticular, very little seems to have been written about the holistic approach to hedgerow management developed through TWECOM, which considers both the economic and the ecological considerations.This project shows that hedgerow management for woodfuel only fully covers the woodchip production costs under very favourable circumstances. This is particularly the case when the price of traditional fossil fuels is low. This type of hedgerow man-agement may be economically marginal, but it is important that hedgerow owners are not deterred from engaging with hedgerow management. The additional landscape and biodiversity benefits are significant, and need to be taken into consideration when assessing the merits of reinstating an active hedgerow management system. .The alder row harvesting trials in West Flanders demonstrate that when you have the opportunity to plant completely new hedges in good accessible lo-

cations, the economics are much more favourable and the system is near break-even. This is because when a hedge has been well designed it can be harvested more efficiently.There are however quite a few unanswered questions which remain after the TWECOM Project. The three year project lifespan was still not long enough to gain experience of the interim mainte-nance and management of hedgerow coppice re-growth between harvesting cycles, such as gapping up hedgerows, pruning hedgerow trees to produce quality wood, and pruning or side-trimming hedges back to keep roads clear. More research needs to be carried out into the storage, drying and screening of woodchips. It is incredibly satisfying and energetically efficient when problems can be solved by making use of waste products from other processes, such as using waste heat from biogas plants to dry woodchip. In this situation, it appears that forced or active drying of woodchip is cost-effective compared to natural drying through self-heating because there are no dry matter losses.We can conclude that when appropriate machines and processes are used, hedges can indeed be harvested to produce a local, renewable, sustain-able and carbon-neutral source of woodfuel.

Figure 24. Coppice regrowth from a roadside hedgerow in the Bocholt district of North Limburg in Belgium.

© B

EN

NY

September 2015Kathleen Bervoets - Coördinator ABC Eco²

For further information on Harvesting hedgerows for woodfuel, please go to the Results section of the TWECOM website: www.twecom.eu

Here you will find further information about:• The hedgerow harvesting machinery trials carried out by The Organic Research Centre in the UK in

2014-15. • A guide to harvesting woodfuel from hedges, produced by The Organic Research Centre in

September 2015.• The alder row harvesting and woodchip drying trials carried out by Inagro in West Flanders,

Belgium in 2014-15.• The Green Heat publication produced by Inagro in 2015.

The TWECOM page of the Organic Research Centre website, http://www.tinyurl.com/TWECOM is also a useful resource where you will find many documents relating to hedegrow woodfuel, including the Biodiversity protocol.Include links to RLLK and the Hedgerow vision plan, DIPLA

ACKNOWLEDGEMENTSThis guide has been produced based on the experiences, knowledge and findings gained from hedge-row harvesting machinery trials carried out under the TWECOM Project. These were carried out by agrobeheercentrum Eco2 and Inagro in Belgium and by The Organic Research Centre in the UK.This best practice guide has been written by Kathleen Bervoets, agrobeheercentrum Eco² Coördinator and Pieter Verdonckt from Inagro, with contributions from Meg Chambers and Mary Crossland from The Organic Research Centre, UK. It was translated into English by Meg Chambers. Many thanks to Benny Vangansewinkel and the farmer-contractors from Agro|aanneming who carried out the hedge-row harvesting work and shared their expertise in making these trials work.The production of this best practice guide has been possible thanks to funding from INTERREG IVB NWE through the TWECOM Project and the province of Limburg.

Diestsevest 40 3000 [email protected] www.agrobeheercentrum.beIBAN : BE07 7360 0263 8666 BIC: KREDBEBB BTW: BE 0849.422.565

T. 016 28 64 64 / F. 016 28 64 39

Landschapsbouwers aan het werk

0123

9

TWECOM best practice guide on hedgerow harvesting and machinery

Documents

Transcript of TWECOM best practice guide on hedgerow harvesting and machinery