Attack of the drones to fight tree rot in Scotland

DRONES more commonly ­associated with the war on ­terror are to patrol the skies over Scotland in a bid to eradicate diseases that threaten to wipe out swathes of forest.

The unmanned planes are smaller than conventional drones and armed with high resolution cameras to capture images that will help woodland managers spot telltale signs of fatal fungal infections in trees.

A trial carried out by the Forestry Commission Scotland at Carradale on the Kintyre peninsula used drones to map the spread of Phytophthora ramorum, a fungus which has recently spread from rhododendrons to larch – forcing estates to fell thousands of trees in a bid to contain the outbreak. The aerial devices also took to the skies over the west coast to assess storm damage in some of the most inaccessible parts of the country.

Now a study carried out for the Forestry Commission suggests that every forestry manager in Scotland should have access to a small-scale drone to improve all aspects of woodland management.

“Only the wide application and routine use of this technology directly by forest managers will enable the technology to deliver its potential benefits, cost effectively,” said Ian Thomas, a chartered forester who helped compile the study. “This means every forestry manager having the technology in the boot of their car, and knowing how to use it.”

Thomas, who monitored the Carradale trial in August, said that the cameras on board drones can spot the early signs of disease in trees better than most other methods of detection, including foot patrols. “A lot of these diseases have been tucked away unnoticed in forests where access is very difficult,” he said. “With this, you don’t have to set foot in a ­forest to see if there’s a problem, so you don’t have the risk of potentially transferring the disease to another forest, which can happen during ground surveys. The rhododendrons [at Carradale] are completely inaccessible. Using one of these you can get really detailed images, not just of the leaves but the veins on the leaves. It worked really well.”

Costs for hiring the Unmanned Aerial Vehicles (UAVs) are £1,000 to £2,000 a day, which forestry experts ­admit is expensive. But they argue it is more economical than the existing method of paying for helicopter surveys at around £1,000 an hour.

The remote-controlled drones have GPS technology on board and can be pre-programmed to map a specific area.

Thomas acknowledged that people living in the woodland areas where drones will be used might have privacy concerns about the prospect of overhead cameras capturing high-resolution images. But he stressed such issues were “negligible” because of the ­remoteness of the locations and the short flight times.

“I can understand why people would think, oh my God. The thought of drones up there surveying people is the most depressing thought ever, but from a forestry management point of view, being able to see from the air is a marvellous thing,” he said. “I think it will improve the standards of forestry management in Scotland. There’s a lot of potential for this.”

The drones used by the Forestry Commission are supplied and controlled by Scottish firm Cyberhawk, based in Livingston, where staff meet strict regulations on flying the vehicles for commercial ­purposes.

Stuart Thomas, Cyberhawk’s survey manager, said: “The benefits of UAVs over ­helicopters include flying ­below the clouds. Full-sized manned aircraft often have to stay above a certain height. We are the only company in Scotland doing surveys and inspections and it is definitely a growth area.”

But he warned against giving drones to estate managers to use the devices themselves. “Some people might feel that that’s the next step, but it would need some changes in the legislation,” he said. Drones are already used in other European countries to help manage forests and the Forestry Commission in Wales is working with the Ministry of Defence to introduce unmanned devices there.

Thousands of trees have been felled across Scotland after record numbers of new cases of Phytophthora ramorum fungus were found in larch trees this year. This and other diseases, linked to a rise in imports, threaten Scotland’s growing timber trade and if left unchecked could prove as devastating as Dutch elm disease, which wiped out millions of trees.

Hugh Clayden, the Forestry Commission’s tree health ­policy adviser, said the drone trials were part of a concerted effort to increase early detection of disease to limit damage.

He said: “We need to raise awareness in the forestry sector that we’re now likely to be increasingly getting pests and diseases. If you haven’t spotted a disease in the first four years it’s very difficult to eradicate, so we have to learn how to live with them.

“Helicopters are good for the big surveys we do because they can cover the ground faster but they are obviously expensive. These remotely controlled aerial vehicles are much cheaper and can be used on a much smaller scale by owners of small woodlands who want to satisfy themselves that their trees are OK. People have to know what they’ve got. It’s not rocket science. Are your trees healthy? If not, what’s the cause and what can be done?”

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