SHAW’S WIRE ROPES IRON TEST
It’s production thinning with a difference as Rotorua-based contractor, Conan Hemsworth, steps outside his comfort zone with a Komatsu 951 wheeled harvester.
THERE’S AN OLD SAYING THAT GOES: IF YOU KEEP doing the same old thing, you’ll always end up with the same result. In these highly uncertain times, foresters are understandably more conservative with decision-making in order to protect their businesses, people and homes from the ravages of an overstocked Chinese market (again), lower log prices (again) and something completely out of left-field, like the Covid-19 virus.
So, it’s refreshing when someone steps outside their comfort zone and tries something completely new, both to them and much of the industry.
Rotorua-based contractor, Conan Hemsworth, is one of those people.
When his clear-fell contract with Hancock in Kinleith Forest finished a little over a year ago, Conan could easily have throttled back and relied on his two remaining crews with Port Blakely to sustain the CMH Contracting operation. Yeah? Nah.
He decided to give something else a go. Production thinning… with a difference. Using a wheeled harvester instead of a tracked base.
Wheeled harvesters have become a hot topic among thinning crews, with a handful operating around the country in place of tracked machines.
But it would be wrong to reference this trend as a ‘wheels versus tracks’ war.
There are good arguments for and against both options, and it just comes down to whatever suits a contractor’s circumstances, the forest owner’s objectives and the working environment.
A wheeled harvester made sense for Conan Hemsworth when he decided to pitch for a thinning job with Timberlands in Kaingaroa Forest that he heard about when his Kinleith contract wound up. He’s not new to thinning. It’s where Conan started 20-something years ago after returning to New Zealand following his OE in Wales, working in a variety of forests, as well as playing rugby.
Conan’s early thinning experience was as manual fall and trim and then as an operator of a forwarder and compact tracked harvester.
Drawing on that background, Conan proposed an entirely new approach in Kaingaroa, which fitted in with the thinking of the team at Timberlands. They, too, were interested in experimenting with wheeled harvesters to production-thin their
burgeoning estate.
Not only will there be fewer trees to thin and less volume per hectare to extract, under the upcoming structural timberonly regime, they’ll be growing closer together and Conan says: “Someone needed to do something different and wheeled harvesters seemed to be the way to go.
“Europeans harvest a lot of wood around this size using wheeled machines and they make it work. Like me, Timberlands were a little bit nervous, but they were looking to have a contract out there trialling a machine and I wanted to give it a go.
“The reason I went for wheels is partly environmental, but also the standard of quality of what I leave behind. Low impact on ground soils and no root plate damage. There’s less compaction and disturbance with wheels.”
All good in theory, but before putting that into practice, Conan needed to do more research, especially on which wheeled harvester would best suit his plans. There’s plenty of choice these days, mostly out of Europe, but not only did the machine and its associated head need to be right, the choice of supplier did, too.
Eventually he whittled it down to one of the products from Komatsu Forest, which pioneered wheeled harvesters in Scandinavia back in the Valmet days. Importantly, the Komatsu Forest NZ operation is based on his doorstep in Rotorua and there’s solid back-up from Australia, where wheeled harvesters are popular in thinnings, which means parts/back-up are only a short flight away.
And the machine itself? Conan settled on a Komatsu 951 sixwheeler. But it wasn’t his first choice.
“Initially, I was looking at the smaller one, the 931, but I thought if I’m going to have a go with a wheeled harvester I probably need to go with something bigger, with a bit more strength to it,” says Conan. “The 951 is not overkill for thinnings but it is probably the top end of what you’d want to put in here.”
That decision was confirmed with a trip to Australia to see Komatsu wheeled harvesters in action, although Conan would alter his views on machine size once he understood them better.
“To be honest, I didn’t know anything about wheeled harvesters when I started looking,” he says.
“Last time I was in thinnings was 15 years ago and the machines were probably a bit lighter back then and the form of the wood wasn’t great. That’s why you needed something more robust. But the form has improved quite a lot and so have the wheeled machines and the heads.
“I went over there to see if they could actually cope with this work, specifically the heads that the factory supplies with the machines.”
In Australia, Komatsu 951 harvesters used in production thinning operations mostly run heads made by Komatsu because the Swedish engineers design them to perform in unison.
The head chosen by Conan to match his new 951 is the Komatsu S172, which is based on the Log Max 7000 that has been upgraded by Komatsu Forest since it purchased the specialist attachment company a few years back. It’s a good sized implement, able to cope with larger trees typically found on forest edges, as well as the smaller ones under the canopy.
In Australia, the S172 also matches the size of trees tackled in the final thinning regime.
Conan explains: “They have a three- or four-tier system for thinning before they clear fell.
“There’s T1 for quite young trees that are brought out and go straight through the chipper (their stocking level starts around 1,600-2000), so each thinning takes a little bit more until they get to T4, where the wood is 22 or 24 years old and around 1.2-piece size.
“We won’t be doing wood anywhere near that size here, but it was good to see the same machine and head we’ve got now, handling trees that big. I thought, if it could do that, it could handle what we want to do.
“We then went and had a look at another one in T3 with smaller wood, about 15 or 16 years old, probably more comparable to the wood we’ve got here. Our trees are around 12-to-13 years, but it’s more about height in Kaingaroa, where production thinning takes place when they reach 18 metres.”
Six months on from the arrival of his own 951/S172 combo, now working in tandem with a brand new Komatsu 875 forwarder, Conan is happy with the decision. The plan was then to purchase another if the initial period went well. It did, so the second phase was enacted.
The existing forwarder can service two harvesters, which meant Conan only needed to invest in a companion for the 951. And this time he went with his original gut feeling and ordered the slightly smaller 931. That machine, complete with a smaller head, landed in February.
More on the newcomer shortly – the main focus for our Iron Test is the 951, which has already racked up 1,000 hours.
Put to the test
Driving into the middle of a very dry and dusty Kaingaroa Forest to see Crew 089 and the new wheeled wonders in action, the Iron Test team consists of just me today – don’t worry, Stan Barlow hasn’t been struck down with any flu bug, he was working in Northland and will be back for the next test.
The compartment being worked by the 089 team is a mixture of pruned and unpruned Radiata, planted under the pre-structural regime, so the stocking suits the larger 951, with one in every two trees being removed to bring it down to around 383 stems per hectare. Our test will largely be restricted to one side of a track that operator, Paul Jones, has cut and where he is about to clear a square for the forwarder to stack logs.
I’m used to seeing zero tail-swing tracked harvesters doing this sort of work in Kaingaroa, so the bright red, 22.6-tonne, 8.3-metre long Komatsu 951 is quite a contrast. Even with the reduced stocking levels in this block, you wonder how it can squeeze through the still-tight spaces in here – after all, it is the largest in the Komatsu wheeled harvester range and longer than the 8-wheeled Ponsse Scorpion King we tested recently and the 6-wheeled John Deere 1470 harvesters with Mike Hurring.
Fortunately, its centre pivot turns 40-degrees in either direction, so it can easily move around trees. The cab and crane rotate 360-degrees – the John Deere 1470 does too, but not the Ponsse – and there’s a squirt boom on the end, which further enhances the pick-and-go manoeuvrability.
But what has really impressed Conan is the speed of the 951 and its head.
“It’s fast, really fast,” says Conan.
“When I saw it in Australia, I was really impressed with what they were doing. They showed me some confidential numbers on what it could achieve. It wasn’t BS, we’ve been doing similar numbers since we put
herSe.E” it in
The speed is not just down to the wheels, it’s the combination of the
nimbleness of the base and quickness of the head – “we had to slow that head right down when we started, it was just too quick”. Now they’ve got used to it, the head has been dialled back up to 100%.
Another plus is when the machine has to move between compartments, it can easily be driven without requiring time-wasting transport. With a top speed of 24km/h it’s quicker than a forwarder – requiring only a pilot vehicle when on the forest roads. Wheels on fire, indeed (remember TV’s Absolutely Fabulous theme song?).
Add up all the advantages and Conan reckons overall productivity is probably 40% better than an equivalent tracked harvester. No wonder he’s smiling.
Before I get to see just how quick it is, I want a closer look at the red devil, so Paul shuts down, then raises the hydraulic bonnet and opens other compartments for inspection.
Power is provided by a Tier 3 AGCO 6-cylinder diesel engine (formerly known as Sisu) that peaks at 210 kW DIN (285 hp) at a relatively low 1,900 revs and is transferred to the ground via a hydrostatic transmission driving all six wheels. Those on the front bogie can be fitted with band tracks for extra traction, but the CMH machine doesn’t need them on these relatively flat and easily drained pumice soils.
Conan does, however, need to carry two different size spare tyres and wheels, because the rear pair are larger than the four on the front. The 951 only comes as a 6-wheeler – no 8-wheel option. There is an 8-wheeled 931, but there’s no traction advantage in a forest like Kaingaroa.
Paul points out the daily checks that are easily reached from the ground and should you need to climb up to reach the top of the engine and hydraulics there is a handy stowable ladder. You have to manually attach the ladder, and when the operator wants to climb up or down from the cab, the separate ladder on the front is also manually operated. On the way up to the cab you climb over a large toolbox mounted above the front bogie, before stepping onto a retractable platform in front of the door that folds out automatically when parked.
From the outside, the cab appears quite small, but once seated in the air-suspended seat it feels much bigger and not just because it’s an allglass affair. There is a lot of room around the seat, enough for someone to stand behind. Plenty of storage spaces, too. And a little pie warmer drawer that we’ve seen in Komatsu forwarder cabs previously. You can even option a chiller box, which would be great for keeping drinks cool in this glass bubble.
A big surprise is the THREE ways you can steer the 951. There is a small steering wheel that Paul says he only uses occasionally, mostly when moving between locations. Plus, he can steer through the righthand joystick or via a small toggle on the joystick pad.
“I mostly use the toggle – it’s much quicker and easier,” says Paul. All the other controls are fairly straightforward. On the right is the slew and the main boom, while on the left is the dipper arm and rotator for the head. There are toggle switches for the saw and feed on the left and the selection is made on the right.
The head is optimised, but as there are just two cuts – pulp and a saw log – Conan says it sometimes gets turned off, which can confuse the system when it’s switched back on, as it has trouble deciding what needs to be done. Best leave it on all the time.
A daunting start
Paul has been with CMH for around 12 years and although he has worked in thinnings previously, his prior experience is limited to a tracked harvester and manual falling.
“I didn’t ever think I would be operating anything like this,” he says. “When Conan told me what he was getting, I thought, ‘that’s something different, yeah. Quite exciting’. Never operated a forwarder, so this is pretty much first experience of anything on wheels in the forest. It’s much nicer to drive than a tracked harvester, much softer on the wheels and more comfortable.
“When I first got into this cab it was a little bit daunting actually. It’s a lot longer than an excavator and in here you have to be very precise driving it around. They don’t move the same. The swivelling in the middle and walking over stuff, not jerking about, and it leans differently to an excavator. And it’s way quicker… it’s just like whoaaaah!
“But once you get used to the speed it’s hard to go back. We did dial the head back at first but not now I’ve got used to it, although it did take a while.
“On the whole, it’s very user-friendly. Such good visibility, you can see down to the ground right in front and then up to the tops of the trees. You don’t even lose much sight with the boom on the right, because it’s always moving.”
For added comfort, the 951 features crane damping, cab suspension and a slewing damper, and the cab comes with automatic levelling (20° forward, 22° rearward and 16° either side) but Paul prefers to manually adjust it.
He says: “On auto it’s constantly moving and adjusting, and in here (Kaingaroa) it’s not really necessary. I prefer to level it myself when I’m working. The only setting I have is that as soon as you stop, it will level it up.”
Both Paul and Conan agree that it’s probably not as stable as a tracked machine when picking up a whole tree with the outstretched boom over the side, even though the wheels have been filled with water to help anchor it.
And in spite of the length of the 951, Paul says he doesn’t have any troubling manoeuvring inside the canopy, adding: “The lines (of trees) in here are pretty good so it’s not too hard to cruise through – someone did the planting job well. Other plots we’ve done are a little bit tight, but we’ve got through.
“Working inside the trees I can reach heaps with that squirt boom. There’s a wide row every five and I tend to go three-and-two and I have no trouble reaching to get the trees I want. The crane can handle much more than I’m cutting in here. Pretty awesome, really. And there’s two cameras facing rear, one right up the top of the cab and the other on the tail.”
He also likes the harvesting head, which is “way lighter than anything I’m used to – it falls very nicely and is just so quick”.
The S172 harvesting head weighs in at just 1,675kg and measures a relatively compact 2,222mm in height, including the rotator. It features two rollers, with four delimbing knives and just a main saw with a 900mm bar. The rollers will power stems through at up to five metres
per second and the arms open to accept a tree of 713mm diameter, so it will probably tackle a 1.2 piece size.
Paul saddles up again to demonstrate how the Komatsu combo performs, manoeuvring inside some of the standing trees to show how easily the big base operates within limited space. The squirt boom allows him to extend the head out to reach trees up to 10.3 metres away. And it hangs onto them nicely, bringing them down in a very controlled manner without breaking – not surprising, since the average piece size is only around 0.25-to-0.33.
No sign of any hesitation in the various operations, even though Paul is working the crane, head and driving the base at the same time. Again, not surprising given the hydraulic set-up, which is load-sensed and utilises a three-pump system, called 3PS, with one dedicated to the drive train and the other two working either separately or combined. They can also work at different pressures and rarely, if ever, max out.
The speed of the head, the slew and crane settings are adjustable through MaxiXplorer, which governs the machine’s nervous system and can be set to suit individual operators. It also self-calibrates to maximise efficiency, reduce fuel consumption and extend component service life.
The system on the CMH machine supports mobile coverage, with live data streamed back to Conan and it generates reports for Timberlands. These can be very detailed, including production results, GPS locations, tracking, mean breast height data, grades cut (off what stump), even things like reverse feed of the head, boom and arm movements, time between trees, time to process and cut. Such useful information can help a contractor when pricing similar blocks.
If there’s no mobile coverage an app uploads all production data which transmits automatically when back in contact.
Timberlands can send cut plans remotely, add in skid sites and block data, compartment numbers, 2-tree length, access points and evacuation locations.
Hazards, such as swamps, tomo’s, cliffs, terrain issues and historic sites can also be logged at the push of a button.
The system allows Komatsu Forest technicians to call up the machine, with the operator’s permission, to check systems and they can even use the high-mounted camera for visual assessment.
Another feature of MaxiXplorer is an antitheft system whereby the operator must log in to start the machine, or use a remote key with a unique ID.
The next step could see the operator not even in the cab but working at a remote location. But not today.
Future investment
As Paul stretches the boom to its maximum to the side to reach a large stem, I note that it does rock on its wheels and even lifts them slightly, so operators
need to keep this in mind with heavier wood. Being around 7 tonnes lighter than a comparable tracked base is one of the tradeoffs for causing less disturbance to the soil and tree roots.
Paul also needs to keep an eye out for old tree stumps, as the ground clearance is only 670mm.
An interesting feature is how two large lights on the rear of the 951 light up whenever Paul puts the machine into reverse, as well as sounding an audible alarm, just like road-going trucks. A good safety point.
And the main lighting package itself gets a thumbs-up from Conan, who says: “In the dark you can probably see 20-to-30 metres in front. That’s good because our plots use a 16-metre radius and you need to see what you are leaving and what you’re going to be tackling next.”
Fuel use is better than a tracked base, but Conan doesn’t let on by how much, just adding: “I’m happy with what it’s doing.”
Servicing is every 250 hours. Same as an excavator base, says Conan: “We’ll stick with that because you do need more work on machines as they get a bit older.
“But when I purchased this, I bought an Uptime Kit, which is basically $20,000 worth of parts that Australia said are probably what you are going to need. That kit covers both machines for aspects like wiring looms, solenoids O-rings – all the stuff you may have issues with. Paul Roche (Komatsu Forest NZ) and Australia have put together a checklist of what we may need to keep an eye on, too, around bolts that do come loose from time-to-time and that’s mainly with the head.”
He also invested in a central lubrication system and electric hydraulic filling system, but there is no fire suppression system. Instead, Komatsu Forest installed a spark suppression system on the exhaust and there are plenty of hand-held extinguishers if required.
Throughout the very hot summer season, Conan has been impressed by the cool running of the engine and hydraulics, saying: “It doesn’t run hot at all. The oil temperature sits around 55-to-60 degrees and the engine temps sits around 75-to-80.”
Not bad for a machine on a very high work tempo, which sees it produce around 15-to-20 tonnes an hour.
Before leaving crew 089, I follow Conan to the other side of this compartment, to where the brand new Komatsu 931 is working inside the canopy. It looks very similar to the one we left a few minutes ago, just slimmed down a bit to 7,525mm in overall length and 2,726mm width. It’s even 100mm narrower than a normal 931, thanks to smaller tyres, ready to become the frontline machine when the crew moves into the structural timber plots, where the final stocking will be 50% higher, leaving less room to manoeuvre.
“As we move into higher stocking levels it will come into its own and I’m sure it will be the right machine for the job,” says Conan.
But that is a story for another time. NZL