New Zealand Logger - - Iron Test -

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.nzlog­ 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...


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