The family and herd showing how an ancient practice is saving the future of Scotland's forests

The hoofprints come from his herd of draught horses — North Swedish stallions — who extract timber from forests up and down the country.

His family-run company — Celtic Horse Logging — has been endorsed by King Charles, who named Mr Lenihan as one of his "countryside heroes" in Country Life magazine for his work with horses. The Lenihans also won a national award for ‘Best Woodland in Britain’ for clearing trees above the so-called Beatrix Potter wood — Tarn Hows in the Lake District — once owned by the Peter Rabbit creator and now in the hands of the National Trust.

Guided by Mr Lenihan or one of his six sons, the heavy horses heave felled trunks through the understorey, carefully navigating wildlife in a way no machine can.

“It’s amazing to see how birds and deer stay put while we’re working,” he said. “They’re not afraid of the horses.”

While the term ‘horsepower’ was coined by the Scottish engineer James Watt more than two centuries ago, ‘horse logging’ is proving to be thoroughly modern in an era defined increasingly by environmental limits.

“The harvesting method we use is carbon neutral and sustainable,” said Mr Lenihan, who is currently based in Aberdeenshire.

“We store more carbon per cubic meter extracted than any other harvesting methods available today.

“It’s powered by nature — by hay and grass — and the by-product is fertiliser, which goes straight back into the soil. More people are starting to think about forestry’s environmental impact. It’s not just about growing trees; it’s an entire ecosystem.”

Each horse weighs around 600kg, their muscular frames more reminiscent of wrestlers than farm animals. Yet, despite their bulk, their impact on the land is light.

“You’ve got roughly 150kg per hoof touching the ground,” Mr Lenihan said. “That’s not going to impact the ground much.

“When we finish working a woodland, within a time period of one week you cannot tell we have been there.”

The hoofprints leave dimples in the earth that can hold water on the hill and prevent run-off during downpours. Meanwhile, mechanised forestry relies on machines weighing several tonnes, which compress soil and can disrupt sensitive sites.

“Conifers are usually planted in marginal land, and this is usually in the upper catchment areas,” he said.

“The ground can become so compacted under those wheels it’s like concrete. This can lead to flooding and the run-off into rivers and lochs can raise the acidity levels in the water which can be hugely damaging for species like the Atlantic salmon.”

Richie Miller, director of the Deveron, Bogie and Isla Rivers Charitable Trust and the River Deveron District Salmon Fishery Board in Aberdeenshire, said he supports the sensitive approach of the horse-human partnership for a number of reasons, including reduced soil compaction, soil erosion and run-off.

“It is possible, depending on the volume of trees felled at one time, that there could be impacts on local streams, including the lowering of pH, at least on a temporary basis,” he said.

Back on the forest floor, Mr Lenihan described how the motion of dragging timber over the ground can boost natural regeneration: “You can see it scarifies the ground, working a bit like a rake, and you get new growth coming through."

The forestry industry is pushing for a rapid increase in timber production to reduce the UK’s reliance on international trade. The sector regularly points to Britain importing around 80 per cent of its timber, making it the world’s second-largest importer.

Mr Lenihan, himself a commercial forester, accepts the need for a robust timber industry. He said some 90 per cent of harvesting is there to be done using machines. The problem, he said, is the remaining ten per cent on the sensitive sites — SSSIs, archaeological sites and land next to rivers, lochs, burns and feeder streams.

“Because there are so few people doing what I do, machines are still going into those places,” he said. “We just can’t put Scotland and environmental forestry in the same sentence with that going on.

Scottish Forestry said it recognises some sites require a more delicate approach and confirmed that the use of horses can be an effective and sustainable method for managing timber on sensitive sites. The government agency said many woodland owners have taken other steps to reduce the impacts of machinery, including the use of smaller machines and cable systems to remove timber.

However, Mr Lenihan remains unconvinced when it comes to any ground machine use in sensitive areas.

“Machines work in straight lines through a forest,” he indicated with his hands through a wooded area.

“They take everything out in their path to get to what they need. You end up with wide corridors of light with trees leaning towards one side and woods that are more vulnerable to windthrow. Also, what happens if you have to harvest large timber in sensitive areas? You are going to need big machinery.”

With a horse, he argues, selection is precise: “We can remove a diseased tree, a damaged tree, or a fallen one without touching the healthy trees around it.”

That selectivity, Mr Lenihan claims, is the only harvesting method that can actively increase the value of a woodland. "I can confidently say the forests we’ve done selective thinning in haven’t blown down.”

Critics point to the slower pace of horse logging meaning a higher cost for extracting timber. But Mr Lenihan counters that, claiming the apparent efficiency of heavy machinery masks hidden costs.

“Some of the land we work on has been intact since the Ice Age,” he said. “Once it’s damaged by machines, there’s no price put on that destruction. That’s what I find alarming. And sometimes roads leading to sites can be damaged by machinery which adds to the cost.”

Beyond the forest, horse logging brings tangible benefits to rural communities. The forestry sector north of the border supports some 34,000 jobs, according to a study commissioned by Scottish Forestry. But Mr Lenihan said when it comes to contributing towards rural communities, horse logging brings is a more lasting benefit.

“Contracted people in forestry often aren’t from the area,” he said. “They come in, do the harvesting, take the cash back to where they are from.

“We’re a tiny ecological business, but we depend on a network of about eight or nine small businesses. Farmers supplying hay, farriers, vets, metalworkers, feed merchants. They rely on us and we rely on them. That’s a community.”

The horse logger said in the decades he has spent working the forests with his noble steeds, he is occasionally told they ‘belong in a museum.’ But Mr Lenihan is unapologetic. “If being sustainable, powered by nature and supporting rural livelihoods is judged to be old-fashioned,” he said, “then we’re heading in the wrong direction.”