How will new engine regulations affect woodchipper purchase options?

Forst ST6 Woodchipper - image: Forst
Forst ST6 Woodchipper - image: Forst

With new engine regulations taking effect next month, Sally Drury looks at buying options and tests latest models.

Forthcoming changes to engine legislation will have an impact on the machinery we choose for grounds maintenance. It is all down to diesel emissions. The ongoing programme of legislation aimed at reducing emissions from diesel engines requires engine manufacturers to develop new models to meet strict limits and manufacturers of machinery fitted with diesel engines are obliged to use the compliant engines within a specific timescale.

As a result, we have already seen a rise in price in some larger grounds care kit where new, efficient,
low-emission diesel engines have been required. Now woodchipper manufacturers are presenting their solutions to (EU) 2016/1628 — the legislation limiting emissions from diesel engines, extended to include "non-road mobile machinery". The key date to note is 1 January 2019, when Stage V requirements come into force.

Non-road mobile machinery includes a wide range of equipment commonly used by landscapers and arborists. In addition to mowers, we are now talking about kit such as self-propelled skid steer, stump grinders and, yes, woodchippers that are powered by engines within the range of 25hp to 49hp (19-37kW).

The bad news is that most existing diesel hydraulic chippers in that power bracket will not meet the requirements of the new regulations so, by the key introduction date of 1 January 2019, customers buying a new diesel chipper will find that machines are fitted with the new type Stage V engines. But these can cost double those they replace and in most instances will require the machine to be redesigned — adding further to the cost of your woodchipper.

Arborist 130: 6in-capacity unit designed as a low-cost entry point hydraulic chipper - image: Greenmech

Petrol option

Perhaps the answer is to opt for petrol. The manufacturers certainly seem to think so. In preparation for the new regulations, woodchipper manufacturers have been busy developing fuel-efficient petrol-powered machines as well as looking into the use of Stage V engines and associated costs.

GreenMech points out that with the legislation requiring all new diesel engines over 19kW (25hp) to include diesel particulate filter technology, it is likely that the cost of diesel power units will increase. To offer its customers a cost-effective alternative to diesel-powered chippers over 19kW, GreenMech has introduced its new Arborist 150P model.

In its discussion paper on the engine legislation changes, Suffolk-based manufacturer Timberwolf says it will be offering Stage V diesel engines, but it is also offering customers the option of a range
of petrol machines. The paper explains: "Stage V diesel engines will be more expensive than the recently launched petrol and current diesel offerings due to the mechanical fuel systems being replaced with more complex and costly fuel and emissions-cleaning systems."

It continues: "In addition, the new diesel engines will require the higher-quality EN590 standard of diesel. This is available either from petrol station forecourts as ‘white’ duty-paid diesel or from bulk fuel suppliers as the same EN590 standard but dyed red and only for use in machinery, thus saving on
the duty."

The new EN590 standard for diesel is critically important. Failure to ensure this standard will lead to engine damage. In contrast, petrol is of a uniform standard, hence there is new-found interest in machines fitted with petrol engines. Timberwolf has been busy extending its low-emissions petrol product family, developing three new petrol variants to give customers choice.

Huge impact

Chipper manufacturer Forst is taking a similar view. "The new engines-emissions regulations coming into force in 2019 will have a huge impact on the industry and it’s vitally important that we introduce a new Stage V compliant machine to ensure our customers can be fully prepared for these changes far ahead of time," says director Doug Ghinn.

"Diesel engines will continue to be popular in the arboriculture industry, but it’s important that operators are aware that petrol engines can maintain the power and robustness that diesel engines provide, with the added benefit of being quieter during operation."

Ahead of the changes, Forst has introduced the ST6P as an extension to its popular range of 6in (150mm) capacity machines. Powered by a 37hp V-twin petrol engine, the woodchipper not only weighs less than 750kg but is also said to match the strength and performance that users expect of Forst’s diesel-powered machines.

"The introduction of the ST6P not only delivers exceptional performance and reliability but also ensures users don’t have to incur costs to obtain the necessary license to tow a machine over 750kg, offering true value to tree surgeons and contractors," says Ghinn.

Specifically designed for contractors, arborists, landscapers and estate managers, the ST6P achieved its sub-750kg category rating through a lighter engine, GRP panels and a shorter chassis. This allowed Forst to utilise the same chipping chamber, flywheel, hopper and feed roller system as used on the popular ST6 diesel machine.

The ST6P has features and benefits that should appeal to contractors and tree surgeons, including the ForstGrip feed roller system with crushing power. The top feed roller of ForstGrip climbs in an arc towards the timber, pulling material down towards the flywheel and climbing butt ends to make the infeed grip and break tough forks and limbs. In addition, the machine has an open-top flywheel system to ensure that chips are thrown, not blown, to minimise blockages on wet material and help maintain velocity when chipping. Like other Forst woodchippers, the ST6P comes with a three-year warranty.

After learning about the benefits of the petrol engine machines, north London tree surgery business The Tree Feller invested in a Forst ST6P. The business serves private homes and commercial properties as well
as local authorities and schools, carrying out tree surgery work and general garden maintenance.

Managing director Charles Fowler explains that there were many reasons for opting for the ST6P from Forst. "One of the main factors behind the decision to purchase the machine was because the team and I were so impressed by the throw of the chippings, which is considerably superior in comparison to other machines we have used.

"We’ve always been faced with the problems of clogging and having to shovel wet conifer towards the back of the van, but the ST6P comes with an open-top flywheel system with large gusseted fraught fins at the rear, combating the cause of blockages and firing chips to the back of the van — subsequently allowing the team more time to focus on the job in hand."

Fowler continues: "As well as that, the level of control we’re able to have over the roller speed and also the size of the woodchip is seriously impressive, considering the compact size of the machine. The one-touch operating buttons are also much more user-friendly as they’re located on both sides of the hopper. The fact that you can lock the hopper down makes it more secure too. It really is a great piece of machinery that offers everything you could ask for from a robust woodchipper. In addition, it is powered by petrol so it has lower emissions and is cleaner-burning, which is a nice added benefit."

Initially, The Tree Feller only used the ST6P on basic tree reduction and garden clearances, but being impressed with the performance it is now using the unit for bigger jobs.

High capacity: TW 230PAHB built to handle large volumes of material and has quad-force hydraulic rollers for crushing power - image: HW

Large volumes

Timberwolf also has a sub-750kg 6in petrol machine, offered in two variants. The TW 230PAHB and
TW 230PWHB high-capacity machines are intended for handling large volumes of material and feature 230mm by 160mm feed openings, quad-force hydraulic rollers for crushing power and a braked chassis. There is a choice of 37hp Briggs & Stratton Vanguard V-Twin or 32.5hp Kubota WB972 petrol engine, and throughput is recorded at up to five tonnes per hour, making it suitable for time-sensitive roadside work. The discharge adjusts through 280° and average chip size measures 18mm.

Horticulture Week took a TW 230PAHB to a school in the village of Cotmanhay, just outside Derby, where Broomfield College staff and students were clearing ground ready for landscaping works (see box, below). Hardwood material and brash was put through the unit.

With a towing weight of just 608kg, allowing transport behind smaller commercial vehicles, Timberwolf offers the TW160PH entry-level model. Compact and ideal for work where access is restricted, it stands on an unbraked chassis, is powered by a 22hp Honda petrol engine and features hydraulic feed and auto feed control.

But the flagship of the TW petrol range is the 280PHB. Powered by a Kubota WG1605 four-cylinder petrol engine, this machine boasts 8in (200mm) capacity for serious arboriculture and forestry tasks. It has a reported output of 6.5t/hr and delivers chips averaging 18.5mm.

Speaking of the petrol range, Timberwolf sales and marketing director Guy Marshlain says: "We have developed this series of machines in anticipation of the new engine legislation, to ensure that we can continue to offer the comprehensive choice of exceptionally productive and user-friendly chippers that our customers have come to expect.

"Any concerns about the suitability of petrol power for chippers will be instantly allayed by these powerful, economical machines, which we believe will offer outstanding service to arborists, landscapers and estate managers for many years to come."

Arborist 150P: introduced to offer customers a cost-effective alternative to diesel - image: HW

Arborist unveiled

GreenMech has also been developing and engineering new product in response to the changes in emissions legislation. As long ago as Saltex 2017 — the sports, amenities and landscaping show held at Birmingham in November — the company unveiled its Arborist 150P woodchipper (pictured above).

The diesel Arborist 150 is already the top-selling chipper in Europe in its class, but by installing a high-output Briggs & Stratton air-cooled twin petrol engine, the company now offers an alternative close-to-similar performance to the higher horsepowered diesel 150 — but at a much lower cost.

A 37hp petrol engine is fitted as standard to the Arborist 150P, giving impressive throughout of material up to 6in (150mm). Like all Arborist chippers, the 150P is designed with the same deep-beam, high-tensile steel chassis construction for strength and reliability. Insulating steel panels provide noise suppression and these can be quickly removed for access to routine maintenance points.

The chipper has a generous 970mm by 790mm infeed hopper, aiding bushy brash reduction, while the 150mm by 230mm letterbox-style infeed throat opening enables heavily forked branches to be fed easily and so reduce chainsaw cuts required. The twin vertical hydraulic rollers crush wood material and the electronically controlled "no-stress" feed system reverses the feed roller to relieve the chipper blades and allow the rotor speed to maintain optimum chipping speed. GreenMech’s patented Disc-Blade system is fitted as standard to give up to 150 hours of chipping before resharpening is necessary. It all adds to output.

Also fitted with a petrol engine is the Arborist 130 — still a 6in-capacity machine but designed as a low-cost entry point hydraulic chipper. It is a simple-to-use machine, road-towable, of traditional format and engineered for the disposal of brash. Power comes from a 23hp Honda petrol engine and it stands on a deep-beam, high-tensile strength steel chassis. The letter-box infeed measures 150mm by 230mm. GreenMech lent Horticulture Week both petrol woodchippers for a test at Trowel Garden Centre, located on the outskirts of Nottingham (see boxes, left). Arboriculture students from Derby’s Broomfield College had already cut down hawthorn, silver birch and other woody material to clear a site for redevelopment.


Hot on the heels of its ST6P, Forst introduced the TR6P this year. Another 6in-capacity woodchipper, but this time tracked, the TR6P is fitted with the same 37hp petrol engine as the ST6P. As with the ST6P, the engine makes for quieter operation. According to Forst, the engine is far more cost-effective compared to diesel alternatives, but with no compromise on quality or performance. Weighing 1,200kg, the TR6P can track fast and utilises the same chipping chamber, flywheel hopper and ForstGrip feed roller system as on other Forst models.

Jensen woodchippers, supplied in the UK by TH White, are well known for a wide selection of large machines, including models on turntables or tracks. Buyers will find new Jensen machines fitted with Stage V diesel engines where required. At the smaller end of Jensen’s portfolio is the compact A530 — a best-selling series for years and now extended to include a 6in petrol model. The A530 Petrol has
a Briggs & Stratton Vanguard 35hp (26.1kW) engine and features a no-stress device and electric buttons as standard. The braked model weighs just 700kg.

So will your next woodchipper be diesel or petrol? You can go for sub-750kg, 6in or 8in or even opt
for a tracked machine and still enjoy the benefits of petrol power, but you should always try before you buy. It is also worth noting that users of existing machines can continue to operate them under the new legislation and will be able to sell-on a second-hand diesel woodchipper or buy a second-hand machine. Timberwolf confirms that it will continue to take them for trade-in purposes and it will still be possible to purchase a second-hand diesel chipper from its dealers. 

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