Q: Do I need a shredder, a chipper or both?
A: If you are mainly dealing with woody material and timber, you should opt for a woodchipper to reduce the waste into woodchips. If most of the material is soft and green, perhaps wet and contaminated with soil and stones, you should use a shredder. Things such as bedding plants, hedge and shrub prunings, brambles and cut herbaceous material should go through the shredder.
Where both types of material require processing, you have a choice of going for a combination machine — a shredder with a small chute on the side to take slender timber perhaps up to a couple of inches in diameter — or a vegetation processor like the Saelen models that are capable of tackling both woody and soft material. In the event that you are generating a lot of timber in excess of 100mm in diameter, you are best off investing in a dedicated woodchipper.
It is also worth remembering that a lot of commercial shredders are also capable of shredding cardboard. Some industrial shredders will take the lot — branches, tree roots, pallets and window frames.
Q: We are a small garden contracting firm. Is it worth spending on a shredder?
A: There are sizes to suit all needs. If you are a contracting firm working out of a small van, you could invest in a small unit to process waste material — clippings and prunings — on site. The resulting material will be easier to handle and will take up less room when you cart it away. You could even offer to leave it for the client to compost and reuse.
If you are looking for a small, easily portable shredder, be sure to choose one that can be lifted or ramped into your van and will fit through the gates where you work.
Q: Are there larger shredders that can be moved easily on site - say round an estate?
A: Several self-propelled shredders are available, such as the Eliet Maga Prof from Pinnacle Power. Some are offered on tracks, the latest being a version of the Saelen Cougar from Eric Hunter. There are many more that are supplied on chassis for towing that could easily be moved by a pick-up or perhaps a lawn tractor, quad bike or all-terrain vehicle.
Alternatively, you could opt for a PTO-driven shredder so that you can move it around on the tractor and then use the tractor to power it — always assuming that you have a suitable tractor.
Q: What other factors should be considered when buying a shredder?
A: The major priority is selecting the right size of machine for the volume of material that needs to be processed. But you should also check that the machine has sufficient power to tackle the types of material for which you want to use it. Speed of operation and throughput will also be important where large volumes of material are likely to be encountered.
Mobility is another important consideration. It may be better to store green waste at a central point and then hire a large machine to tackle a mountain of material in one go. In this instance, you will also need to think about how the material will be loaded into the shredder. You may need a front-end or skid-steer loader. The very large industrial shredders sometimes come with their own loading grapple.
Before purchasing a machine, check that it has all the necessary standards markings and comes with guarding around moving parts. If it is a manual-loading shredder, check the height of the loading chute or conveyor to avoid future back strain.
Q: What factors should be considered for the risk assessment?
A: The process of shredding green material can result in flying debris, including irritants and sharp objects. These can be a danger to the operator, passers-by and property. It is important that the operator wears protective clothing, including a visor. Do not wear loose clothing that could be caught in the shredding mechanism. Bystanders should be excluded from the area of work. Do not operate the machine close to vulnerable property.
There are risks of burns, lacerations, amputation and other injuries associated with powered machines with moving parts. Shredders should be used by operators who are trained and competent and have read and understood the manual. Care should be taken fuelling the machine and the fuel should be stored appropriately.
The machine should not be run without first having undertaken the required pre-start checks and maintenance schedules should be up to date. If on-site repairs or adjustments are required, ensure that the shredder is turned off — and unplugged if electric — before carrying out any work on the machine. Electric shredders should be used in conjunction with a mains circuit breaker and should not be used in wet weather.
To avoid tripping and slipping, keep the ground immediately around the shredder free from the materials to be processed and always wear appropriate non-slip footwear.
Shredding on the move
Take a trip by car or train and it's almost certain that hawthorn, gorse and similar vegetation will obscure the view across the countryside for some part of the journey. While we need varied vegetation for environmental and ecological reasons, there are instances where control measures are needed for safety.
Often the cost of maintaining the encroaching jungle is deemed too high and work is only tackled when the road or rail is affected. This usually means bringing in the chainsaws. Once the timber has been cut, woodchippers are brought in to reduce the material to a size that can be left to rot on site.
The risk of slipping makes working on embankments hazardous and it can also be tiring. Specialist equipment may be required for road verges, such as chippers and shredders mounted on turntables. Machines with extendable legs — such as Greenmech's SAFE Track chipper — are ideal for embankments.
But what if vegetation on verges and embankments could be kept under control using equipment that shredded the material as it moved? That question was posed by the Deutsche Bahn Railways in Germany and Greenmech came up with answer — the Multi Task.
The Multi Task is built on similar lines to a skid-steer loader. To the rear of the cabbed unit is a 120hp Deutz engine. This powers two hydraulic pumps, one that drives the steel tracks and the other to the 1.5m mulching head at the front.
SAFE Track stabiliser legs allow the chassis to remain level on a 30 degs slope. Added to this, the operator can remain level on angles beyond 35 degs by electrically swivelling the seat 20 degs either way. The mulching head is capable of cutting and processing brash and timber up to a thickness of 100mm.
A number of other machines can be fitted with forestry mulching kit. Bobcat, for instance, offers the Forestry Cutter for use with compact tracked and skid-steer loaders.
The unit has 24 fixed carbide cutting-teeth over a width of 1.52m and is designed for continuous work on bushes and trees with timber up to 130mm in diameter, intermittent use for trees with trunks up to 230mm and occasional use on trees up to 300mm.