THINNING YOUNG STEMS OF RADIATA PINE IN KAINGAROA Forest is a highly mobile, high speed business. The margins in production thinning are so thin (pun intended) that the smallest amount of downtime can affect the economics of the job.
Operations have to be super-efficient and super-reliable. If there is one contractor that knows how to make thinnings work, its Jensen Logging. The Rotorua-based outfit has been thinning in Kaingaroa for more than two decades, which included a break when Timberlands paused to allow the age class of the trees to catch up. Jensen returned when production thinning resumed and they’re still in the game, having built a reputation for doing a damn good job.
The key, they emphasise, is to get the machinery choice right. Then everything else should fall into place.
When NZ Logger last caught up with the Jensen team a little over six months ago, our focus was on the harvesting side of their thinnings operation, looking at their first Cat 521B and SouthStar QS450 combo.
Production thinning in Kaingaroa has moved to a whole new level in recent times and the Jensen business has had to shift up several gears, too, employing multi-machine tactics in order to meet the 900-to-950-tonne daily target.
Thus, the number of harvesters working for Jensen’s two production thinning crews in Kaingaroa has now grown to four Cats and four Komatsu XT430-3s – all fitted with the same SouthStar heads.
But putting wood down on the ground is only half the equation. Getting it to the roadside in a timely manner is just as important and the choice of forwarder is crucial.
These crews are served by four forwarders, all from the same manufacturer – Komatsu Forest.
No surprises there. Russell Jensen is a long-time fan of the Komatsu brand and its predecessor, Valmet. He also has an excellent working relationship with John Kosar, the National Sales Manager for Komatsu Forest in New Zealand, which paid off when Russell needed to expand his forwarder fleet recently.
John was able to secure the first Komatsu 875 to arrive in Australasia for Jensen Logging. No mean feat, as there’s good competition for this size forwarder.
That pleased Russell, who says: “It was good to get this one quickly and into work. We’ve known John for a number of years and he’s always prepared to go the extra distance for us.”
The Komatsu 875 was introduced in Europe last year as the successor to the 865. Jensen Logging is very familiar with this size forwarder, having purchased an 860.4 – the model replaced by the 865 – in 2010 to work in Kaingaroa when Timberlands re-started thinnings. Then a pair of 865s were added later, as the
thinnings programme grew, one by Jensen Logging and the other by contract operator, Rory McCormick, who is still working his. The latest expansion led to the purchase of the 875.
Interestingly, neither the 860.4, nor the 865 were traded in by Jensen. Both machines continue to operate in the same superthinnings operation, working alongside the new 875 to service the eight harvesters between them.
NZ Logger is back in Kaingaroa to put the new 875 to the test. It’s something of a reunion for us, as we first caught up with this crew more than six years ago, not long after the 860.4 had arrived, and the operator on that machine, Karl Fisher, is now at the controls of the 875. Back then, we were doing a Breaking Out feature, looking at how the whole crew works. This time we’re here to focus on the forwarder.
If we were looking at this machine in Europe, we’d probably be in a clear-fell operation, not thinnings. In the Komatsu Forest forwarder pecking order, the 875 is the second largest model in the range, sitting below the 20-tonne capacity 895. With a carrying capacity of 16 tonnes, the 875 is classed as a big forwarder over there.
It could be inferred that it is a little on the big side for thinnings in New Zealand, especially in its latest guise, as it’s wider than the 865.
But high productivity is the name of this game and pushing the envelope with the size of machines is paying off handsomely for Jensen Logging (you may recall that the Cat 521B we Iron Tested in February was also right on the limit size-wise).
The extra width in the bunk has added a further one tonne of capacity to the 875, compared to the 865, which carries a tonne more than the 860.4, so at least the growth pattern is consistent between the generations.
It’s not actually the width of the bunk that is the main issue here, it’s the balloon tyres that the new Jensen machine is wearing in order to improve traction and reduce damage to the environment. In place of the standard 710/45x26.5 tyres, it has a set of eight 800/40x26.5 tyres, which push the overall width out to 3,170mm, compared to 2,980mm.
Normally, an extra 190mm wouldn’t make a blind bit of difference to your average forestry machine, but in production thinning every millimetre counts when squeezing between standing trees. By way of compensation, around 330mm has been shaved off the overall length, so the 875 can turn a little easier than the 865 when empty.
Fortunately, in Karl Fisher, the Jensen team has an outstanding operator who knows how to pilot the Komatsu through the tight stands without leaving a mark – on machine or trees. You only have to look at the two previous Komatsu forwarders he drove to see the care he takes with equipment and how his example has
been followed by drivers who have succeeded him.
“That 860.4 has done 13,000 hours but you’d never know to look at it – it could easily be mistaken for one that’s only done 2,000 hours,” says Russell Brown, Operations Manager for Jensen Logging.
While the extra dimensions of the 875 are now at the top end of their requirements for production thinning, Russell B says there was really no discussion about moving away from Komatsu forwarders. Their reliability and performance has been faultless, he says, and the expectations are that the latest of these eightwheelers will follow in the same tracks.
Compare the three generations of forwarders in the Jensen stable that are currently working in this compartment and the recipe hasn’t changed a great deal – each model has built on the strengths of its predecessor and brought a few more advances to the table. Sit them side-by-side and they look remarkably similar. In fact, it’s hard to pick the difference between the cabs on the 875 and 865 from the outside, even though there is a tad more room in the newcomer. A larger air grille in the side of the remodelled engine compartment and larger grab handles on the B and C pillars being the easiest differences to spot.
Karl has noticed a little extra leg space in the cab and if you look closely at our photo on page 28 of the three Jensen machines lined up together you can make out the extra length in the larger
side window between the 875 and 865.
The main visible point of difference between Karl’s former 865 and his new steed is the bigger crane sitting between his cab and the bunk.
It’s the optional 145F model that has more grunt and lift power compared to the standard 135F – it boasts 145kNm lifting torque, against 127kNm, and 38.0kNm of slewing torque, against 28.7kNm. Quite an improvement. There is no difference in the reach, however, the squirt boom still extends out to 10m. More on that as we get into the test proper.
To provide the extra grunt for the larger crane the hydraulic system has been upgraded. Bigger pumps now supply 360 l/ min at 2,000rpm, against 290 l/min in the older machine. The hydraulic reservoir has also increased from 122 litres to 150 litres.
The other major external change is the increase in the size of the bunk. The standard model comes with 4.7m2 capacity, but the Jensen machine has the optional extra wide bunk, giving it 6.4m2. Both are appreciably bigger than the bunks specified for the 865.
All this extra bulk takes the gross weight of the Komatsu 875 up to 19,900kg, almost three tonnes greater than the 865.
To compensate for the increased machine weight and its larger payload, the 875 gets a more powerful engine. The 7.4-litre AWI 6-cylinder unit is an upgrade of the previous Tier 2 engine, not the Tier 4 Final unit that NZ Logger previously stated was going to be fitted to this model in our market – that’s still reserved for Europe and the US. Power output has lifted to 185kW DIN (248hp) at 1,900 rpm, compared to 158kW DIN (215hp) in the 865. Torque is also up by a good margin and whilst the 1,100Nm peak arrives at 1,500 rpm, there’s actually more than 1,000Nm available from as early as 1,000rpm, resulting in great driveability. Tractive force is similarly boosted to 214kN, compared to 193kN in the 865.
The extra power and weight doesn’t seem to have affected the fuel consumption very much, according to Karl. The machine is very new but he still has a reasonable amount left at the end of a hard day when he refuels the 210 litre tank (which has increased in size from 165 litres).
Power is transmitted to the eight driven wheels through the proven computer-controlled, hydrostatic mechanical transmission. The transmission automatically adapts to changes in engine load due to terrain, obstacles, inclines and crane loads, learning the drive patterns, so it should help to reduce fuel consumption as time goes by and the engine beds in, too.
In the unlikely event that Karl should need extra traction he can summon up locking diffs front and rear.
Over rough ground the Comfort Bogies developed by Komatsu Forest to take the punishment out of the ride are a welcome piece of technology, alleviating some of the stress for the driver. The ride can be further improved by specifying the Comfort Ride cab suspension option, but this wasn’t deemed necessary for the Jensen machine.
One option that is among those to be ticked by Jensen Logging is an on-board fire suppression system – pretty much mandatory for machines working under the canopy.
Another improvement that’s worth noting: when making the daily checks, Karl doesn’t have to manhandle the bonnet anymore because it now hydraulically opens and closes.
Before Karl and our Iron Tester, Stan Barlow, head into the forest to grab the next load, I manage to keep them out of the cab long enough to see how this enlarged version compares to its predecessors.
Forwarder cabs are always a delight to sit in and the grey plastictrimmed interior of the 875 is no exception. The 360-degree view through the deep glass windows makes for a light and airy working environment. Sure, there’s still the matter of having to look through that big grille in front of the bunk when driving in reverse, which slowly gets worse as more logs are loaded. Fortunately, you can also glance at the screen to see the view provided by the optional camera fitted to the Jensen machine.
It does appear to be a little roomier than its immediate predecessor and there seems to be plenty of storage spaces for Karl to utilise, including the optional pie warmer that he uses to heat up his lunch.
Although it is still possible to order the 875 with a steering wheel, Jensen Logging has dispensed with it and their machine is solely steered through a joystick mounted at the end of the righthand armrest. Speaking of the seat, Karl rates this new air rider model as superior to the one in the 865.
“This air seat is much more comfortable than the old one,” says Karl. “You don’t feel the bumps as much and it’s less tiring at the end of the day.”
As before, the seat swivels from forward to rear facing and can be locked in any position in between, to allow Karl to face the direction where the grapple is being loaded up with stems.
One thing he did get changed when the 875 arrived was the European-style joystick controls.
“Theirs have a lot more options that I didn’t really need, so it’s now the mini lever that’s been in every forwarder that I’ve driven,” adds Karl. “They’re good, a really nice feel – you get used to things and when you’ve had something like that for a long time and it works, you don’t want to change.”
When facing rearwards, Karl has the computer keyboard and screen that taps into the MaxiXplorer system, which is a carryover feature from the 865. MaxiXplorer provides a whole range of information and controllability, everything from more precise and efficient machine control to operational and production followups, which can be uploaded to the team at Jensen Logging HQ back in the sulphur city.
And with such a wide expanse of glass, Karl confirms the climate control is more than capable of keeping the interior cool on bright sunny days and pumping out plenty of warming air on sub-zero mornings this time of year.
But there is one area that he does think the 875 has not progressed; noise suppression. He says the engine can be heard more than in the 865 and Komatsu Forest is looking at installing a hush kit to reduce it.
Otherwise, Karl is delighted with the 875 and counts himself lucky to have been upgraded each time his forwarder was replaced.
It makes up for the one hour-plus drive time between the work site and Rotorua at each end of the day.
This compartment is one of the most southerly in the Kaingaroa Forest, not far from the Napier-Taupo Highway and the crew is looking forward to progressing back towards the main forest, to cut down travel time.
Talking of crew, there’s no sign of any other machines here, apart from Karl’s Komatsu. We did catch a glimpse of one of
the harvesters way down a side road on arrival, but the rest are buried deep under the canopy somewhere.
Karl only moved his machine here a day earlier and the harvesters have moved on, further into the forest, leaving him and the other forwarders to pick up the wood laid down for them.
Having seen this operation from a harvester’s point of view, it’s interesting to return and see how it works for the forwarder operators.
Fortunately, the wood is fairly close to the roadside stacking area (you can’t call it a skid site because it’s not being skidded) so the travel times for our test are quite short. The forwarders can venture more than half a kilometre into the forest to retrieve wood, but that’s usually the limit.
Karl starts the 875 and there’s room in the cab for Stan to join him and watch how he handles the machine before taking over the driver’s seat.
The grapple is stowed snuggly in its cradle inside the bunk as Karl heads down the road and turns into a row he’s already made a start on, while I walk behind on foot to film and photograph the proceedings (don’t forget you can view video of all our Iron Tests on the www.nzlogger.co.nz website and facebook page).
Karl is reversing in, because the vision is better when the bunk is empty and he can manually lower the grille to improve his view even more, but says he can see through the bars well enough, so doesn’t bother. He can always check the camera screen if he needs more visual input.
In spite of the overall terrain being flat, it’s actually very lumpy inside the canopy. These trees are the third rotation plantings and there’s still stumps and scars from previous harvesting history, so the pathway is littered with obstructions. The Komatsu Comfort Bogie copes very well with these irregularities, not only improving the ride and driving properties but also providing additional ground clearance.
The undulations give the beefy articulated joint system (which is now cast) a real work out, though traction obviously isn’t a problem on the volcanic surface, so no need to fit tracks to the tyres.
Karl is also doing a great job of navigating the narrow gaps and doesn’t appear to be having any issues with the machine’s wide tyres.
When we discussed it beforehand, he said: “On narrow tracks, the extra width from those tyres can make it more challenging to get through, so you have to pick your channels more precisely. I’m hoping the tyres will make a difference on wet ground.”
If width really is a problem, buyers can always go for the standard tyres and take the optional FlexBunk, which features an adjustable bunk that can be wound out or in when the going gets tight (it also has height-adjustable bolsters).
On the subject of bolsters, Jensen Logging removed one bolster from each side of the bunk, as the three remaining ones can easily hold the 5-metre stems in place. It also means there is one less obstacle during loading and unloading, which Karl as now begun.
The big new crane sports the larger Komatsu G36 grapple, so it can grab more stems in each bite. In theory, it means he can fill the bunk more quickly, but that’s dependent on the number of stems bunched on the ground. Unloading is definitely faster.
Using the squirt boom, Karl can reach out and grab stems from as far as 10 metres away, which is very handy due to the restricted manoeuvring space. No issues with lifting or swinging a full load, thanks to the bigger crane. And, in spite of its extra size and weight, the new crane feels every bit as fast and smooth as the old one.
Even though the stems are scattered along both sides of the track, it doesn’t take Karl long to fill the bunk. He’s got scales on board that tell him when he hits the 16 tonne limit.
“I could put a few more in, but there’s no point overloading the machine, you’ll break it,” says Karl. “If you keep to the maximum weight and make your turnarounds faster, you can still move a lot of wood.”
Emerging into the daylight, Karl still keeps the 875 in first gear, as it’s just a short drive to the stack. For longer journeys out on the road it can reach 20km/h in top gear, as before, but most of its work under the canopy is carried out at walking pace.
Karl stacks the stems in double quick time, as there is no need to sort them into grades because this wood is all heading to the pulp mills.
Tutorial over, Stan swaps places with Karl and heads back into the woods with two rules ringing in his ears: “Don’t hit the machine or a tree.”
And, in spite of his lack of experience in forwarders he manages to keep to those rules as he drives among the trees and loads the bunk.
Being just inside the canopy, the visibility is pretty good and there’s no need to use the new LED lights around the roof and on the crane – they do make a difference to early starts and dull days, however, says Karl.
Stan’s impressions on this experience are conveyed in his Iron Test column on page 30.
Just as he was getting comfortable, it’s time for Stan to end his experience in the hot seat.
It may have been relatively brief, but this experience has confirmed in our minds that the new Komatsu 875 is fulfilling the role demanded by Jensen Logging, even if it is pushing the envelope with regard to its size.
It could probably hold bigger loads, but operator, Karl Fisher, wants to take care of the Komatsu 875.
Above left: The squirt boom extends to 10 metres to allow for a wider sweep on either side. Above right: The new crane is bigger and more powerful than before. Below: Even with the wider, yet lower profile tyres, the new Komatsu 875 still has...
Facing page: Regular operator, Karl Fisher, watches as our Iron Tester, Stan Barlow, brings another load of stems aboard. Above: The new Jensen Logging Komatsu 875 brings a full load of 16 tonnes out of the forest. Above, right: No sorting at the...