Low Impact

Low impact harvesting equipment is important for the welfare of forests and many manufacturers are developing compact and light harvesting equipment solely for this purpose.

Thinning is the most important operation that is carried out in forests that are managed for commercial timber production. By removing the smaller, weaker, poorer quality and dead and dying trees the remaining good quality standing trees benefit as they don’t have as much competition from the understory for nutrients during the growing season.

When commercial thinning is carried out correctly the footprint from the smaller, low impact machines is almost non-existing, this is also beneficial in forests where there is a lot of outdoor activities which are open to the public

Commercial thinning of woodlands has many advantages;

When correctly carried out it can be instrumental in preventing wildfires by removing many of the smaller stems in a forest compartment. It improves the overall health of stands of timber which helps to protect it against diseases and insect attacks.

Thinning the timber will generate an income to the forest owner and will increase the value of remaining crop.

Thinning opens the canopy and allows sunlight to reach the ground which stimulates the growth of grasses and other herbaceous plants that provide wildlife food which  improves habitat conditions for wildlife.

At the start of my forestry career, in 1976, as a chainsaw operator my first job was felling and de-limbing full tree length Sitka Spruce for skidder extraction in first thinnings.

We were removing a single row with small chevrons either side; it was a nightmare to work as the crop was tight. Luckily the trees were small enough to cut off the stump and drag the butt backwards to get the tree onto the ground for snedding.

All the tips of the trees had to be clear and dragged together where possible to make chokering for the skidder easier and they had to be cleanly snedded so they were not dragging a load of brash out with them.

If you left pegs on them life was hell at piece time from the crosscutting squad as having to keep the road clear of brash increased their workload between drags.

I was employed by the Forestry Commission (FC) and our piecework rate was set at 30p for each tree, managing over 30 hairy trees a day in the tight crop was bloody hard work.

The trees were extracted with a Malvern skidder which I think was a Roadless 75 4WD tractor converted to a forestry skidder by the FC’s mechanical engineering department

Most of the timber was converted into 1.1m lengths for Bowaters Pulp Mill at Ellesmere Port but in addition we supplied our own little “in house” fencing mill which had a McConnel saw bench and Cundy peeler and the Rio Tinto Aluminium plant who wanted 4m thin pole lengths that were used for burning off impurities during the smelting process.

This was not the best method for thinning as the side chevrons meant that some better quality timber was being removed with the remaining crop between each chevron still quite dense.

The only mechanical processor available in the UK that could carry out this type of work was the Kockums GP 822. This was not effective as all the timber had to be manually felled backwards so it could pick up the butts and in tighter spaced crops it would need a double rack taken out to travel.

The trees from the main rack had to be lifted over the standing crop to be processed in the chevrons.

As the equipment used for thinning has evolved so has the quality of thinning being carried out.

There are two important factors needed for successful thinnings; the correct equipment for the ground conditions and good experienced operators who understand the work they are carrying out.

I have carried out a lot of thinnings during my career; I was operating a small John Deere 810B forwarder for quite a while behind a hand cutting squad and then following a John Deere 870 harvester.

Recently I got the opportunity to operate a small low impact Gremo 750F forwarder and was following a Komatsu 901XC harvester on first thinnings.

With modern low impact harvesting equipment thinning operations can be carried out to very high standards and this will yield an excellent valuable final crop.

Production will be much slower as damage to the remaining crop must be avoided; the harvester operator has to be precise with his felling and has to stack the processed wood where there is enough room for the forwarder to load without skinning trees

To achieve this contractor carrying out this work must be paid accordingly, if the rates are set too low then good trees might be selected to boost production and they are unable to invest in the correct equipment.

I contacted Ben Clinch the forestry manager for Moray Estates who carry out an extensive thinning programme in their 4050 ha of commercial woodlands in Moray and Doune.

Ben joined the Company in April 2012 and is responsible for the management of all the Company’s and Moray family’s woodland assets.

“For me as a forest manager who regularly generates more volume in a year from thinnings than from clearfelling I keep in mind that as well as any early income one of the main objectives of silvicultural thinning is to continually improve the quality of the remaining crop.  To achieve this goal I seek to pull together harvesting operations that limit stem/root damage (preventing butt rot) and also limit soil compaction so as to maintain healthy root performance and yield.

For a good number of years I have been really disappointed by the standard machine choice on offer to carry out early thinnings and operations on sensitive sites.  The shift away from small specialised thinning machines towards larger ‘jack  of all trade’ machines began several decades ago, and from the contractors perspective for very good reasons (1) staying uber competitive on price per tonne during a sustained period of pretty low timber prices, generally on clearfells, (2) timber sales being increasingly sold on a competitive standing sale system where main consideration £/t generated for that job in isolation is the main consideration for those choosing tenders.

The use of too large machinery in early and mid-rotation thinning in UK conditions means that in many cases a forester should probably not bother to thin in the first place! 

This is a sad state of affairs, flying in the face of best practice in sustainable forest management as all too often the remaining crop and forest soil post thinning is seriously compromised.

A well respected multi machine harvesting contractor in NE Scotland who undertakes later stage thinnings and clearfells in my managed woods has said to me more than once that getting the right operator to do thinnings is key.  Now I don’t disagree with that at all, he is right, but sticking a highly skilled thinnings specialist on a machine built for the job is OPTIMUM and the results speak for themselves.

Width and ground pressure is the primary balancing act for thinnings.  All too often in 1st & 2nd thinnings you see damage on the rack edge trees after trying to squeeze a 2.9m wide machine down a single row rack.  To overcome this sometimes two rows are taken out.  Doing this compromises both selection (crucial in non spruce crops) and also opens the stand to a higher chance of windblow. Machines travelling on two row of stumps early in a rotation also leads to more entry points for butt rot (if stumps are treated at all!) and sometimes even bolster damage up the stem as bogies slide and sway off stumps.

Reducing overall width by putting on 600 tyres on 10t class forwarders that are grossing at >24t laden is not the answer either as ground damage is generally excessive in our wet and warm climate.

Over the past 4 years we have taken our early thinning programme out of the standing sale system and have instead sold at roadside.  This has enabled us to commit a regular volume to specialist thinnings contractor who has invested in kit (especially forwarders) that can achieve high quality thinning.  We have had Novotny forwarders (both LVS 520 & 720) pulling out thinnings with great success.  Our early thinnings contractor has now settled with a Gremo 750F which hits all the right notes for us and you see the improvement in the crop.

In addition to conifer thinnings we harvest around 1000t of beech per year.  One of our local firewood/forestry contractors runs a Falcon F40.  We and a number of other Estates/Farmers have found this machine and others in the category like the Alstors to pull out numerous loads on fragile sites with surprising efficiency and low fuel usage.

There was a time when a Valmet 820 was considered a beast of a machine; shifting baselines mean that many consider any smaller machine is a toy, nothing can be further from the truth.”

Here are some of the specialised harvesting machinery which have been developed purely for thinnings

New Neuson Forest 204HVT

I saw this tracked levelling harvester make its debut at Austrofoma last September and comes in either 2.5m or 2.7m widths so is ideal for all types of thinnings.

The engine is a John Deere EU Stage V EPA Tier 4 6 cylinder 219hp engine with a hydraulic, auyo variable speed reversible fan.

There are various options for cranes, the one I saw was fitted with a Waratah CH6 parallel crane with 11.5 m reach and had an AFM 45 harvesting head fitted (other head options from other manufacturers are available). It has a smart tip control system for easier operation.

Vision is excellent and the cabin has been redesigned and is spacious and comfortable. The front window is made from 3 layer 21mm thick Kasi Glass, 12mm is the legal requirement but this offers operators much better protection from chain shot.

Automatic levelling with a front cabin tilt of 30° with +/-15°side to side, ground clearance is up to 610 (depending on track configurations) and tail swing is minimal or working tight thinnings.

During harvesting and travelling it requires an engine speed of just 1500rpm and will use 10-12ltrs of fuel per hour.

As with all Neuson tracked harvesters access for servicing and repairs is excellent.



Neuson Forest 103/104HVT Harvester

The 103/104HVT is a tracked levelling harvester with a John Deere 4 cylinder turbo diesel 115hp motor, high slewing torque and SCR technology for lower emissions.

It is ideal for harvesting first and second thinnings and is capable of achieving up to 16m³/hr

We held UK demonstrations with the 103HVT (same sized machine but with a 103 hp motor and without SCR) in 2017 in first thinnings on a steep, heavily branched Sitka Spruce forest in the Lake District.

It performed very well with a LogMax 4000 harvesting head (other heads are available) and achieved excellent production.

The 104 HVT will tilt 25° forward and +/- 15° sideways. It has a track length of 3.460m and a width of 2.5m with a short tail swing so is able to work in single row first thinnings. It will perform well in steep and wet, boggy conditions.

Optional track types and widths are available.

Ground clearance is 520mm and it has a low centre of gravity which allows good stability when at the full 9.3m reach of the crane.

It is a comfortable cabin with good vision, servicing and maintenance is easy to carry out with good access to all areas.

There are a number of optional extras available including central lubrication system, X Crane Control, mini joysticks, cameras, etc



Gremo (Now EcoLog) 1058 H5 8WD Harvester

I attended the launch of this harvester in Sweden last year where it was harvesting first thinnings averaging just under 0.1m³ in a mixed conifer and birch forest.

It was a steep site with a lot of large boulders that had to be avoided.

The Gremo has a 200hp Stage V Cummings engine with Rexroth hydraulics; it is 2.78m wide and has 580mm of ground clearance. The demo model had a 10m reach Mesera 221H series crane but it is also available with an 11m reach crane.

This model had the new Gremo active bogie system which can be switched on when travelling on steep ground or driving over unavoidable obstacles.

It has a 200hp stage V Cummings engine and the hydraulic pumps are from Rexroth. The head on this harvester was the SP 461 (this one was going to a forestry school) but it is normally fitted with an SP 561.

The operator, Lars Ryttberg an experienced Gremo operator, had been operating this harvester for 80 hours and as it needs an engine speed of only 1450rpm it had been using just 8.45ltrs of fuel per hr.

The harvester weighs 16 tonne and it has the very fast DASA Forester user friendly touch screen computer system.

Access for servicing and repairs was superb, the cabin is spacious and well laid out and vision is clear and uncluttered.



Gremo (Now EcoLog) 750F Forwarder.

I spent over 400 hours operating this forwarder in first thinnings at Doune forest for Moray Estates.

The last Gremo I had operated was my own TT12 back in the 1980’s and it was a dinosaur compared to the 750F.

This model was fitted with 600mm TRS Tyres and was 2.47m wide, with 500mm tyres it is 2.27m wide so both are ideal in first thinnings. It weighs 11 tonne’s empty and has a generous payload of 8.5 tonne, steering angle is +/- 40° and it is powered by a Cummings 4.5l 164 hp turbo diesel engine.

It has a Cranab FC53 6.5m reach crane with a Cranab CR 200 grab.

The first thinnings were single row with a selective thinning either side, there were a few 3.7m logs but it was mostly 4m chip and 2.5m pallet. The hauling distance was well over 1km in places with some steep inclines when loaded.

Vision, comfort and cabin layout are superb with plenty of room to stretch out. Servicing, maintenance and refuelling are simple and straight forward to carry out. Access is good to all components and the cabin is easily tilted for getting to the hydraulic pumps and transmission.

I was averaging about 7m³ each load and at over 1km was averaging over three loads every two hour. It was taking a good distance in each rack to get fully loaded and the emphasis was on the quality of work not quantity.

I thoroughly enjoyed operating this forwarder, on rubber tyres and fully loaded it had the best grip of any forwarder I have ever driven on the steep inclines. It is manoeuvrable and the crane was powerful and easy to operate in the tight thinnings.

On the long haul with uphill steep loaded extraction I was using just over 6ltrs of fuel and extracting about 12m³per hour. On short hauls of less than 500m I was using just over 5ltrs of fuel for around 2 ½ forwarder loads approx 20m³.



FMS 575 Harvesting Head

The 575 head is designed and manufactured by Forest Machine Services (FMS) at their workshop in Wark, Northumberland and the sticker on this head says it all “Made in Great Britain by Men in a Shed”

This is a stroke head ideally suited for excavators in the 8 tonne class. It weighs 600kg with a 64cm guide bar, has an 800mm stroke and will cope with stems up to 450mm in diameter. One of the owners had it fitted onto a Whacker Neuson 7.5 tonne 70hp 8003 2.25m wide excavator, FMS carry out the head installation, fabrication and fitting of guarding for forestry use. This normally takes about five weeks to complete.

This harvester can be transported with a tractor and plant trailer which makes it ideally placed for thinning normally uneconomical smaller compartments and shelter belts.

This head was never designed to compete with the much more expensive roller driven heads but is a robust, reliable and uncomplicated design which won’t break the bank.

With the stroke de-limbing design it will work efficiently in light and heavier branched softwoods and hardwoods.

This is a good safe solution for dealing with areas of Ash dieback which are very brittle and would be dangerous for chainsaw operators to work.


Novotny LVS 520 8WD Forwarder

These forwarders are made in the Czech Republic by Strojírna Novotný s.r.o. who is a machine-engineering company that was established in 1981, they specialising in the manufacture of weldments, loaders, and forwarders.

The LVS 520 is the mid range forwarder that they manufacture, it weighs 6.4 to 7.2 tonnes depending on the customers specification and it has a 5 tonne payload. It is poered by a 100hp engine from FTP and the hydraulic system is made by Saur Danfoss.

There is the option of a Cranab FC45 (6.1m reach) or the Cranab FC53 (6.5m reach) cranes and two tyre widths of 500 or 600mm and it can be fitted with bandtracks or wheel chains.

It is 2.1m wide with 500mm tyres and has 440mm of ground clearance.

The cabin rotates 180° and offers great vision, it is spacious with an air suspended, heated seat, mini joysticks and air conditioning. It is well laid out, operator friendly and has good access for servicing and repairs.


Malwa 560 6WD

There are three options available from Malwa

560H harvester; this is available with a Mowi 6.2m reach parallel crane and a LogMax 928A harvesting head with a maximum cutting capacity of 42cm

560C combi; this is a harvester and forwarder which can be converted from one to the other in less than 20 minutes. It uses a Cranab FC45 6.1m reach crane with either the LogMax 928A harvesting head or a Cranab CR200 grapple.

560F forwarder; it has a 5,500kg payload which can be increased to 9,000 when combined with the forwarding trailer. Available with a Cranab FC45 crane with 6.1m  or 8.2m reach, the longer crane is needed if it to be used with the trailer.

All three models have the same cabin and running gear; the engine is a 75 hp Caterpillar Tier 4 Final with an IQAN CAN-bus based control system. The transmission is hydro mechanical by Bosch Rexroth and is separate from the work hydraulics.

The weights of all three models start at 5,400 kg with a width of 1.95m on 500mm tyres. The rear bogie can be fitted with band tracks for soft and steep conditions.



Alstor 840 Pro Combi Forwarder.

I have had the opportunity to operate this forwarder a few times now and it always brings a smile to my face.

Although a little forwarder the engine power, climbing ability and lift of the crane is astonishing.

It is just 1.57m wide and weighs 2,300kg, it can be transported on a trailer behind a 4×4 or large van.

The engine is a three cylinder 25hp Kubota with a hydrostatic 8WD system. It has a 3000kg payload, Palms 5m reach 300kg lifting capacity crane and has Parker flow sharing hydraulic mini levers.

The Pro Combi has the option of being converted to a harvester by fitting a Tapio 160 stroke harvesting head, it can be ordered with the wiring and hydraulics pre installed and is a simple and quick to convert.

The Tapio will process trees up to 250mm diameter and has a 500mm de-limbing stroke which operates at 0.75m/sec. The chainsaw chain is .404 pitch.

A surprisingly roomy, comfortable cabin with good all round vision.

It can be tracked all round to further reduce ground pressure and will travel effectively on ground which is almost too wet and boggy to walk on.



Avesta Vagnen

They produce a quad based forwarder trailer with the options of 3.8 and 4.2m reach cranes. The trailer will carry up to 5.5m lengths and has a roller drive system onto the trailer wheels to give better traction.

The crane and drive are powered by a separate hydraulic power pack and the crane is operated by a two lever control system.

The steel is zinc electroplated plated and then powder coated so it will remain rust free and looking good for many years to come.

The Chassis has a double box frame for extra strength, articulated steering for increased manoeuvrability, hydraulic outriggers for stability, swivel bunks and four towing heights.

There is an integrated winch built into the crane arm to give you more versatility and better positioning. It is perfect for skidding logs from 25m away without having to reposition the trailer.


There are many other equipment options for effective low impact forestry operations but I would be looking at the build quality, availability of spares, the length and what exactly is covered by your warranty.

All equipment fails at one time or another but keeping downtime to the minimum is the secret to running a successful business

Landowners and estate managers employing contractors with this type of equipment are looking at the quality of work as opposed to quantity and this should be reflected in the contract price.

Rab Easton

Find Us On

Neuson 204HVT
Neuson Forest 204HVT
Neuson Forest 103/104HVT
EcoLog/Gremo 1058 H5
EcoLog/Gremo 750 Forwarder
FMS 575 Stroke Harvesting Head
Novotny LVS 520
Malwa 560 Forwarder
Alstor 840 Pro
Avesta Vagnen
Line thinning
EcoLog/Gremo 750F
Selectively thinned between the rows with a harvester

Forest Machine Magazine is written and edited by a forest professional with over 40 years hands on experience. We are dedicated to keeping you informed with all the latest news, views and reviews from our industry.

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