Safety and efficiency should be the bywords of every arb contractor, but the impact of ash dieback and other diseases can put both in doubt. For especially risky jobs, the best option could be to call on the mechanical tree-dismantling services of Corrigan Contractors, as essentialARB found out at its recent demo.
A STORM is on its way to Scotland.
While across great swathes of England, chalara ash dieback has wreaked havoc for tree-care professionals, councils and the public, north of the border it is yet to reveal its full, devastating power.
But it is here. The discoloration of twigs and live shoots, the early signs of the disease, is already evident in ash trees up and down the country. By this time next year, many will have broken limbs and be unsafe to climb. A year after that, just leaving them standing will pose a risk to public safety.
READ MORE: Forestry Commission chief calls for end to 'dogma around conifers'
Recent headlines from England’s dieback battle have not garnered much attention in Scotland. Local authorities have had other priorities to deal with and are likely to be caught on the back foot when their trees start failing. Scottish arborists, the majority of whom still favour climbing over mechanisation, are generally unprepared for a menace which poses such risk to life and limb. When the storm hits, as it surely will, many will have difficult decisions to make about how to proceed.
Corrigan Contractors is one company offering a solution. Based in Ardgour, in the West Highlands, this family-run civil engineering firm has made a substantial investment in top-line machinery and equipment, with a team of operators able to assist arborists with the dismantling of difficult trees.
On a clear morning in September, essentialARB was invited up to its site near Fort William for a demonstration of the equipment’s capabilities – and the team’s skills – in tackling two challenging specimens.
The first was an infected ash, around 100 years of age at the roadside – typical of the sort which will be faced by many arborists in the coming years. Invited guests gathered in the adjoining field, observing – at a safe distance – as it was dismantled by a Hitachi ZX175W-7 wheeled excavator (or ‘rubber duck’) and GMT035 grapple saw.
Providing flexible, tension-free grasping, sawing and controlled felling, the GMT035 features the TTC (Total Tree Control) system, specially developed to make it possible to hold tree parts after the moment of sawing. Not only is the tilt cylinder of the grapple blocked, but so is the movement in all directions in the cardanic suspension between rotator and crane. This provides operators with flexible installation and fixed removal at the push of a button.
The assembled audience – including guests from SSE, Highland Council, SEPA and others – had a clear line of sight to watch as, working from the top, section by section, the tree was methodically taken apart, the capabilities of the grab ensuring that, once cut, each piece could be carefully lowered to the ground.
Sandy Corrigan, one of the company’s operators and brother of founder Shaun, said: “I try to drum into everyone who uses the machine that it’s better to take an extra half an hour or 45 minutes to take a tree down than end up in a bad situation. You don’t want to tip the machine, drop something where you don’t mean to or for anyone to get hurt.
That’s the long and short of it. That’s the whole reason we got into this kind of work – safety.
“We have a small team of highly skilled operators working with the equipment, but the expertise would start with the tree surgeon. They are the ones who would identify when a job is too unsafe for them and that is where we would come in. So far it has been an opportunity to work together, rather than competition.”
Despite the careful, considered approach, it wasn’t long before the ash was reduced to a stump, the excavator showcasing its speed and versatility in a relatively tight workspace.
It towed an EMA MD100X trailer carrying a self-propelled chipper, suggesting that, with the use of remote control, a single operator could come on site, dismantle a tree and chip it directly into a wagon.
However, on this occasion the severed branches were left where they were as it was time to move on to the second demonstration site.
Here, a Volvo FH 540 truck with Palfinger PK78002 crane and GMT035 grapple saw went to work dismantling a huge wych elm afflicted with Dutch elm disease, which had been slowly dying for years.
With a 31 m reach, the Palfinger allows for a safe and efficient system when dismantling diseased or dangerous trees, ensuring the operator can stay safe on the ground, far away from the drop zone. It certainly proved its worth on this site, where to reach the tree it had to navigate a stone wall, BT line and live power lines, with a private garden on one side and a public road on the other.
“The elm was certainly not safe to climb,” said Sandy. “The only alternative would have been to use a cherry picker and take off tiny pieces, put them in the cherry picker and, once over the field, throw them out. That’s very time consuming, causes a lot of impact on the ground and you’ve got the risk for the man in the basket. Plus, should the tree burst while using the crane, you know no-one is in the exclusion zone.
“We wanted to show the crane truck working to its full capabilities and this site does that. You’d have a tough time finding something else that ticks every box quite like it.
"The beauty of the grapple saw is you don’t have to carry something on a low loader everywhere. You just fold it up and take it with you.
“It’s a lorry you can take from site to site, so no additional transport costs.”
The saw’s TTC system again meant cut branches could be carefully lowered to the ground. They were then collected by a Kobelco SK 75SR and fed through a Bandit Intimidator 18XP chipper into a Chieftan Xcel trailer in an efficient production-line process.
While Sandy and others worked to pollard the elm – in hopes it may yet have a future – lunch was generously provided for the spectators and more of the company’s back story uncovered.
Established 15 years ago by time-served joiner Shaun Corrigan, the firm initially stuck to bespoke housebuilding projects, but soon expanded its range of services.
Shaun said: “I began to get fed up with working on building sites that were badly prepared. I wanted everything to be clean and tidy. So I bought some diggers so we could prepare the sites ourselves. Some of our clients wanted bigger, civil stuff done and it progressed steadily from there.”
Over the following years he took on a range of civil contracts, building dams, bridges, roads and hydro-electric schemes, adding to the fleet of machines along the way.
“Most of our work is within an hour’s drive of the Corran ferry,” said Shaun. “And we do a lot of work for large sporting estates. Quite often, when you’re doing jobs like that they want you to be able to tackle everything, including taking trees down. Even though it’s not our primary work we’ll do it. We’re versatile – like these machines.
“We started off doing fairly normal tree work, but it was seeing the progression of ash dieback in the south of England that made me think we should get our own crane and grapple saw setup. It will be the same story up here in a couple of years. I think it will be chaos. Local authorities don’t realise what’s coming.”
With that in mind, Shaun did a bit of research online and approached Field and Forest, an existing supplier with whom he had a good relationship, to find out what was available. The firm was able to supply various pieces of equipment – most notably the GMT035 grapple saws – which were then prepared and fitted by John Craig of JCC, Corrigan Contractor’s preferred engineering partner for forestry modifications.
“John does a lot of forestry-related stuff, including widespread conversions, skyline winches, that kind of thing,” said Shaun. “For anything bespoke, all you need is an idea and a fag-packet diagram and he can make it. You don’t need engineering drawings or structural calculations. He’s that good at what he does.”
One of those bespoke pieces is an excavator attachment combining an Intermercato grab with the saw block from a GMT and a 500 mm bar, an impressive piece of engineering shown working towards the end of the demo.
All told, Corrigan Contractors has invested close to £750,000 in its new range of tree-dismantling kit. It might sound steep, but you get what you pay for and the team is confident its kit is some of the best available anywhere on the market.
It’s already been put to work on a range of jobs, with last year’s storms producing a lot of demand for the team’s services. In the aftermath of Storm Arwen, the Kubelco in particular, with GMT grab attached, proved a star.
Sandy said: “Normal crews that were out would have four or five cutters, but with the grab and the tiltrotator we just had one cutter to deal with anything that was too big for the grab to snap. One specific job, the cutter reckoned it would have taken him a week to do. But we went in and cleared it in four hours. It’s very productive, like a Swiss army knife.”
The demo, the first the team has ever put on, was organised to help showcase its kit and services to a wider audience than its existing client base. Feedback on the day suggested all were impressed, but Shaun worries there’s still a sense among Scotland’s councils and government bodies that ash dieback is a problem for the future, not worth thinking about now.
“Our aim today has been to show people what’s available to tackle dangerous trees, in preparation for the chaos coming our way,” he said. “I hope it’s been informative for people, learning about the different bits of kit, what they can do and how safe and efficient they can make the job.
“I am concerned Scotland’s going to get caught with its pants down. In a year or two, when limbs start falling at the roadside, then I think it’ll draw some attention.”
www.corrigancontractors.co.uk
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