New Zealand Logger
SPECIAL FEATURE – FELLING FOCUS 2
Up in the North Island, another contractor has been using a different fixed felling head to introduce mechanisation to his first thinning operations. It’s hard enough trying to make mechanisation work in production thinning, but extremely challenging for a machine to squeeze through miniscule gaps in a 1000plus stems forest to carry out a first thin. Tombleson Logging has somehow managed to make it work.
NICK TOMBLESON OF TOMBLESON Logging claims there was no big masterplan behind his development of a fully mechanised thin-to-waste operation to be used in young forests stocked with up to 1,000-plus trees.
Instead, he says, it just evolved in response to a common problem.
“We’d been doing fully mechanised logging for years and I could see the merit in a fully mechanised thin-to-waste operation, especially with the issue around finding talent and keeping guys safe. It was just a matter of trying different things to see which would work best,” Nick says.
Today, Tombleson Logging has two mechanised thinning outfits working successfully in forests in Kaingaroa and Northland. These machines are tackling conditions that would test manual silviculture workers on foot and the results are quite astounding. For example, thinning 1,400 hectares per year with just two people. That’s around 15 hectares per person, per week.
“We’ve worked it out that in normal conditions, one machine equals the production of 3.4 guys on foot,” Nick says.
What made it possible was an Austrian built fixed felling head called a Woodcracker.
Woodcracker heads have been used successfully around the world for clearing land, but as far as Nick knew, no one had put them to the task of thinning. Designed especially for small diameter wood, Woodcracker was found to be ideal for felling young trees of first-thin age, ie around 8-to-10 years old.
The Woodcracker is different to any felling head you’ll have seen working in a New Zealand production pine forest to date because it has shears to slice through the trunk, instead of a chainsaw or even a disc saw.
Nick came across the Woodcracker heads when researching various options on the web and approached the West Tech Woodcracker factory direct in late 2016 – today, Woodcracker heads are distributed in New Zealand by Donaldson Mechanical of Hamilton, alongside its own Duxson dangle felling head and grapples, so it’s much easier for other Kiwi contractors to follow Nick’s lead.
The discovery of these lightweight fixed heads was the final piece in a puzzle that enabled Nick and his team at Taupo-based Tombleson Logging to unlock the secret to making first-thinning possible by machines.
“I was lucky to have Ken Holmes, of Holmes Group, as a sounding board throughout the process,” says Nick, who started his logging career with one of Ken’s crews.
“I had an idea of how I could make the mechanised felling work and it was all down to having the right felling head – because Ken was trialling different options in Kaingaroa, he was happy to share learnings and ideas from his experiences, which helped me narrow down the direction I wanted to try up in Northland. Ken’s really innovative and I respected his insights.”
Ken had been using compact Bobcat excavators fitted with a traditional dangle felling head in Kaingaroa Forest for his mechanised thinning trials.
The discovery of the lightweight fixed felling heads from West Tech Woodcracker, allowed Nick to build on the Holmes experience.
Nick says: “Woodcracker have a range of models and for us, the attraction originally was that they had accumulating arms and a single-action knife cut instead of a double
ram cut. The grapple is quite big, too. And it’s a lot prettier than the other heads. Generally, if something looks good, it is good.”
“They were also a lot cheaper than buying anything in New Zealand at the time, when the Euro conversion was more in our favour – it would have cost almost another half again to buy something in New Zealand. And that included shipping and everything.”
So, armed with that information, Nick flew to Austria to visit the West Tech Woodcracker factory, four hours from Vienna, close to the Italian border and not far from where Palfinger loading systems are made.
“They tend to use these heads for land clearing over there, mainly brush and small trees,” he says. “They’ve got some working in South Africa and they’re designed to have a quick hitch to go and clear some trees and then put a bucket on and clear a road.”
Nick wasn’t looking to use a quick hitch for his heads, as they are for felling only and intended to stay on the machine. But they are just bolted onto the dipper arm and easy to take off if required.
He ordered a pair of C250 models – the smallest in the Woodcracker range, which can tackle softwoods up to a diameter of 300mm or hardwoods up to 280mm with its 450mm blade. This model is designed to go onto a base machine of around 7 to 15 tonnes, which got Nick thinking about what he should buy for his proposed thinning project.
He ended up going for Caterpillar 314 zero-swing machines to match the felling head’s capabilities. They’re considerably larger than the Bobcats Ken Holmes had used, but more suitable for the steeper
terrain where the first Tombleson crew was working in Northland.
Those two Cat/Woodcracker combos went to work in a newly-formed crew headed by Nick’s father, Leigh, in Northland two years ago. Leigh was the first driver of the unit, offering driver feedback and developing the process on managing blocks and felling using the new head – input Nick found invaluable.
“These machines will only be as successful as the operator, so it was great to have someone with Dad’s experience helping forge the way,” Nick says.
Forestry is in the blood for the Tomblesons. His father, Leigh, has worked in the industry for four decades. Nick started his career in forestry when he left school at 15, working with Holmes Logging and then Stanaways, as well as short stints elsewhere. In 2002, Nick took the plunge to go into business with his father, starting a fully mechanised clear-fell harvesting crew in Woodhill, Auckland.
Today, Tombleson Logging includes a clear fell crew in Auckland, Leigh’s thinning crew in Whangarei, and a road-lining crew, sub-contracting crew and thinning crew in Taupo, where Nick is now based with his wife Anna and two young sons, Lachlan and Riley.
Nick’s mechanised thinning operations are winning fans around New Zealand. Initially, sceptics didn’t think the excavators would be able to easily manoeuvre within the tight confines of a heavily stocked forest, removing unwanted trees whilst leaving the best ones undamaged.
But Hancock Forest Management backed the concept from the start, giving the fledgling Tombleson Logging thin-to-waste crew an opportunity to have a crack at some of its young forests near Auckland. The machines worked well, so the crew continues to thin for the Hancock north operation today. Tombleson has also thinned forests for Hancock central and Rayonier.
The concept also caught the attention of Timberlands, which has the largest single thinning requirement in New Zealand, needing 8,000 hectares thinned in Kaingaroa Forest every year.
The health and safety factor of not having workers on the ground saw Tombleson Logging win a contract to start thinning to waste for Timblerlands early last year. And that’s the operation NZ Logger is visiting today.
Like the northern thinning crew, the Tombleson Logging outfit in Kaingaroa runs with just two machines, but by the time this contract was signed, the Cat 314 had been phased out by Caterpillar, replaced by the Cat 315F. Instead of using Tier 3 engines, the Cat 315 machines have Tier 4 Final units, which require diesel exhaust fluid, such as AdBlue, to be added on a regular basis.
Nick accepts that the 315F is a little on the large size for the type of work it is undertaking, but there was no real other option: “The 315F is Caterpillar’s smallest machine that has the pump flow required for the head so that’s obviously what we went for.”
Working within the close confines of a tightly planted forest has other drawbacks, such as keeping the Cat engines sufficiently cool. Nick has found the Tier 4 Final technology seems to create more heat than its Tier 3 predecessor, something he’s working with Goughs on.
Of the two new machines, one is running with the original Woodcracker C250 used by the northern crew, while the second has been fitted with the larger C350 model, brought in to deal with the bigger trees in Kaingaroa.
“In Whangarei, Hancock does its thinning at age 8 or 9 years, or 12 metres, which is their optimum tree height, whereas Timberlands is something like age 12,” says Nick. “At the moment Timberlands also have some production thinning blocks with trees aged about 16 or 17 – they want us to fell it because it’s more dangerous for their manual thinners to do that stuff, which is why we upsized the head to the C350 model.”
Nick believes they’re getting closer to getting the equipment right for the mechanical thin-to-waste operations.
He says: “The fixed head and knife gives you better direction – the boys might grab it on one side and then move it across to the other side while it’s still standing. The machine is big enough to be able to cut and then pick the tree up and go around in circles if you wanted to and then put it down. It gives us the ability to cut, place and pick.
“And the knife is low maintenance, with lower running costs. If they hit a rock or something the operator might jump out with a file and sort it, but generally we don’t do anything to the knives – we might do one sharpen every three months. We’ve only changed one knife after a year-and-a-half. It’s really simple, but quite sophisticated, too.”
He also likes the fact that the smaller of the two heads is very light, weighing in at just 900kg, including the accumulator arm – although they don’t use the arm now.
“We just stack to one side because the trees in here are bigger. We found we could get away without using it. We took it off one and everyone liked it so we took them off all of them,” says Nick.
“When you cut the tree it sits on top of the knife and when you cut the next one it keeps stacking up on the knife. And you’ll eventually run out of room on the knife. It’s got a big ram behind it to provide the pressure, unlike some other heads with accumulators, they are accumulating for a drag, whereas we are doing it to get enough to put them down on the ground."
While the Woodcracker has been a success in his Northland and Taupo operations, Nick is still keen to refine and improve. He’s working with Dave Cox at Ensign in Rotorua to develop their own fixed head that will be a little bigger and stockier to withstand the extra challenges presented in Kaingaroa. It will feature shears, too, but no accumulator arms – “we’re just going to stack them with
grapple that’s already there.”
As far as operating, Nick says the two crew members work in tandem and move through each block until completed.
“If it’s flat they’ll generally keep moving down in a straight line,” he says, “but more often than not, ground conditions in Kaingaroa are far from flat. It’s very lumpy in places, littered with numerous stumps from earlier rotations and is criss-crossed with gullies that can be several metres deep.
“The two operators sometimes see each other but in thicker places they may be out of sight. They’ve got two RTs – one on them and the other in the machine – so they can always be in contact. They might be working at different speeds, so one might get ahead of the other one and then they’ll cross over.
“We’ve got a stock standard 3-metre boom on these machines and one with a 2.7-metre boom. I factored in the 8-metre reach, because we need it for the row width – to be able to get two rows either side and access through the middle. I didn’t care how it was configured, as long as it was long enough.”
There are times when the operators still need to wield a chainsaw, for example in
areas where a machine can’t access, but Nick says it’s very rare. But one thing they don’t have to worry about is extracting the wood, because it’s all thin-to-waste.
“We’re just cutting it down and moving on,” says Nick.
“In here we’re only doing one tree at a time and putting it down, because the trees are too big to get any more in. In this block we’re doing pruned block regime, with a lower stocking, to create larger trees. This means we can only cut one at a time, but when we get into higher stocking regimes, we’ll cut multiple trees before putting them on the ground.”
Pulling up at a small clearing where crew foreman Cam Keates has parked his Cat, fitted with the Woodcracker C250 for us to inspect, it’s hard to believe that just two relatively small machines can be so productive, but Nick insists they “can get through the hectares – we’ll get through about 1,600 hectares for Timberlands in a year with these two machines”.
He’s quick to add that the crew working near Whangarei probably won’t cut quite as much because of the different silvi regime and the more difficult terrain. But they won’t be far off that number he reckons, adding: “They’re a more experienced crew that does all the hill country, the more tough stuff.”
Cam has been doing this work just over a year, joined six months ago by teammate Ash Darroch who drives the Cat fitted with the larger Woodcracker C350. Cam put his hand up for the gig as soon as he knew these machines were being introduced into the central North Island. The former carpet layer has been with Tombleson Logging for 5 years and was working on a loader when Nick decided to hold trials for operators to go into the cab of the new Cat/Woodcracker combos.
“I definitely wanted to try it,” says Cam, who was chosen as the driver and pleasantly surprised to be chosen as foreman of the crew, too. He hasn’t looked back since.
The three of us conduct a walk-around tour of the Cat, with its zero-swing tail illustrating a clear advantage for working in such tight confines, only compromised by the fact that the small engine compartment doesn’t provide much opportunity for hot air to escape – no wonder they keep a close eye on operating temperatures.
Both 315F machines were fitted with purpose-built cabs by EMS on arrival in New Zealand, a sensible piece of protection when there’s always the danger of limbs or even whole trees coming down on the roof. Marguard is used for the screens to improve the operator’s outside view, while still keeping him safe.
It’s a tidy machine, but our attention quickly moves to the Woodcracker C250 fitted to Cam’s Cat. It is surprisingly compact, but then it is only cutting down small trees. And I have to agree with Nick’s earlier assessment that it does look remarkably simple – a large blade operated
by a hefty ram on the bottom and two large grapple arms at the top, which are able to open as wide as 930mm (on the larger C350 they open wider, to 1,430mm).
Nick ticked the option box for the 360-degree rotation, which provides the head with a full vertical turn, but it remains fixed horizontally.
I ask Cam if that restricts the operation and he says: “No, it works very well. You have to go in and out and move the machine around, just like a bucket, if you want to move it horizontally.
“But I can pretty much get any tree from most positions. I guess it does limit how you fall, but I haven’t known anything else and I’m used to it and I always position myself right. If there was a tree behind another one that I wanted to grab I could still reach around and spin it, pull it back and then try and cut it.”
Not having any experience with any other felling head, Cam can’t really offer an opinion on how the blade differs from a chainsaw-equipped felling head, although Nick chips in he doesn’t find the shears slow at all, adding: “It’s a 3-second cut.”
Thinning to waste is a numbers game and time is marching on, so Cam climbs up into the cab to provide a demonstration of how well this combo works.
I’ve accompanied manual thinning crews in the forest many times in the past and am envious of Cam being in his comfy, air-conditioned cab while Nick and I struggle through the undergrowth and try not to tear clothes (or skin) on the blackberry. Mechanisation is definitely the way to go.
Despite its size, Cam is able to weave the Cat through the canopy with remarkable ease and position himself to select unwanted trees, cut and lift them to exactly where he wants, instead of allowing them to fall any old fashion. It’s a tight fit in
some places, he knows the spacing formula that is required and can usually pick off trees with that 8-metre reach if there isn’t enough room to get in close.
The trees are laid down in a pattern to provide more space for a person to easily come in on foot afterwards to perform an audit compared to a haphazard manual job.
The machine works fast and, unlike a manual faller, doesn’t tire or have to stop to sharpen or change a saw blade or fill the tank as often.
When Cam completes his demonstration, I ask about the formula he works to.
“We make sure they are spaced well, we’ve got a set number at 5.1 metre a square as a spacing – so the amount of trees in a 16-metre circle we have to get is 31 trees,” he says.
“We try and do two rows either side, depending on the planting. Although in this block we can go down one row and get three rows each side just because of over stocking – there’s one wide row and three smaller ones.
“Every now and then we get out and measure to make sure we get it right, so we’ll have 368 per hectare.”
To make the task even easier, Cam has saved a map on the screen of his phone (Ash uses a tablet) that identifies where he has logged and he can mark trees that he hasn’t been able to get, so someone can return and drop them with a chainsaw.
“I don’t think I’ve logged any of those in this part of the forest, but Nick says in the next block there is stuff that’s going to need manual falling,” Cam adds.
I mention that he leaves the floor tidier than most manual operations I’ve seen and he says: “Once cut, we try to place each tree out sideways to the machine as it’s easier to continue and it looks a lot tidier. When we’re going in to make plots it makes it a lot easier when they are all facing the same way instead of being crossed up.”
Cam likes the Cat 315F and says it’s well balanced, adding: “Compared to the loader I used to be on it’s a lot more stable. And having the head fixed means we have a lot more control. Plus, you don’t have to be careful with the tree because it’s waste.”
In spite of being able to work closely with Ash in the other machine, Cam says it can feel quite isolated compared to working in a large crew, but he doesn’t have a problem with that. In fact, he likes it.
“I really enjoy it and can see myself doing this for a while,” he says.
That’s good feedback for Nick, who says word of these mechanised first thin operations has spread among forest managers and he’s already fielding requests to work for them. Especially as he is able to operate his machines for similar rates paid to manual silviculture crews on thin-to-waste jobs. And still be profitable.
Mechanised it may be, but Nick says you can’t underestimate the role the operators have to play for this type of work to be a success.
“We’re pretty confident in the equipment we’ve chosen and the process we’ve developed but the guys who are doing it every day are the ones who are really driving this innovation and improving it every day,” says Nick.
“We’re always responding to their feedback and trialling new things based on what they’re telling us.”