The story behind Scotland's vertical tree farm in Dundee

THE first thing you notice about the ‘vertical tree farm’ is just how long it takes to spot it. 

Hidden away at the back of a research centre on the outskirts of Dundee, it isn’t immediately obvious which is the building that could soon be leading Scotland’s tree-growing revolution. There’s rarely any doubt when you’ve reached the grounds of your average nursery, whereas this had Forestry Journal checking – and rechecking – the map to make sure we hadn’t taken a wrong turn. Luckily enough, we were in the right place – and what a place it turned out to be. 

READ MORE: Trees grow six times faster in vertical farm than traditional setting

Officially known as the IGS Crop Research Centre – IGS standing for Intelligent Growth Solutions, an agriculture technology firm – the farm shares very little with a traditional nursery. There are some polytunnels at the back, a few portacabins in the grounds, and it’s surrounded by trees, but that’s where the similarities end. Instead, the eye is immediately drawn to its four, white-clad towers – called growth towers – that stand 9 m tall and are the epicentre of the whole thing. It’s in those that a series of trials have proven seedlings can be grown around six times faster than in a typical glasshouse, with some oak and hazel reaching 50 cm in just 90 days (or barely two Liz Truss premierships).

Press from around the world have visited recently. (Image: FJ)

Those are the kinds of results that get people talking. On the sunny October day FJ is in town, it’s joined by both The Courier newspaper and Agency France (who came all the way from – you’ll be shocked to learn – France just to see the farm). Forestry and Land Scotland (FLS) – which is behind the project, alongside IGS – is only too happy for the positive press. Vertical farming isn’t a new concept, but the idea of swapping out herbs, fruits and vegetables for broadleaves and conifers is a relatively untested one.

At the site, FJ is led via an airlock system into a room of fluorescent lights and stacked shelving. It’s striking, as is the size of the place, which feels no bigger than the average school gym. But there are four towers of numerous levels and (up to) 26 trays on each that can produce around three to six million crops at a time. 

It would take more than a few pages of the magazine to describe everything that’s going on in the room in detail – there are lots of gadgets, gizmos and buttons that FJ probably shouldn’t touch – so let’s get to the heart of it all. How did this project come to be? 
“Devolution has led to a number of unintended consequences,” says FLS’s tree nursery and seed resource manager Kenny Hay, a forester of more than 30 years. “One of them being that for Scotland, we’ve lost a significant number of the trees we can produce ourselves. We lost the English nurseries, which, by and large, were mainly producing plants for us. We went from 60 per cent self-sufficiency to 25 per cent. We saw that as a fairly risky position to be in. 

“I got involved in an email chain asking what I felt about this system, which had been visited by NatureScot colleagues. They asked if this could this be good for planting willows. My initial reaction was that it sounded like hydroponics on stilts. 

“I visited with three or four colleagues and we were absolutely blown away by the potential of the place.” 

After some short discussions, it was agreed to begin the trials. In the first instance, these saw conifers – such as Douglas fir (which Kenny described as the most difficult) – grown with some ease. Next, it was on to broadleaves; another success. 

“We reckon the seedlings would spend three months in this place,” Kenny says, describing how FLS’s own vertical farm would work – if it can secure funding. “We’d have two crops to give us the amount we need – and that’s between three and five million in each crop. We need six to eight million. The first crop would grow for a month then we would put it into the glasshouses, while the next gets two months in the tower. Then they’d be ready to go out. 

“What would we do with it for the other nine months of the year? We’ve just proven we can grow commercial-quality broadleaves in 90 days – how many crops of broadleaves would you like? 

FLS’s Kenny Hay says the farm is a ‘no-brainer’. (Image: FJ)

“Now, it’s really a question of what happens next. That’s not for me to say. But  my opnion is it’s a no-brainer.

“I don’t see a negative. The long term would be fundamentally better. We’re getting a lot of push for diversifying our commercial species, but some of them are not offered to the trade because they are difficult to grow. This gives us a fantastic opportunity to maximise growth.” 

The mechanics of the process are extremely clever. The towers – the technology in them was originally designed for vending machines but also comes from motorbikes and car plants – feature trays across each level, with around 1,100 LEDs per tray. Fully automated – the tech is so smart, it can function for several days without WiFi or electricity if something were to go wrong – it uses what’s called ‘ebb and flood hydroponic technology’ to care for the crop. This includes watering them via pipes that flood the bottom of the level, the frequency of which can be adjusted depending on need. The climate can also be changed for each level. Any problems – overwatering was one in an earlier trial – have quickly been ironed out. In terms of actual yield, Kenny expects it to be around the same as a traditional setting. “There’s not been any ‘Oh my God, what’s happened to this?’ moments.” 

Species proven to grow on the farm include silver birch. (Image: FJ)

And just like a vending machine delivering chocolate bars, each level can be ‘grabbed’ by a mechanical arm and moved to the bottom. That’s done through a cloud-based system that can be accessed on a tablet; a demo of which is provided by Csaba Hornyik, IGS’s plant scientist, and the gathered journalists are certainly impressed. 

“There was a farmer called Henry,” says Dave Scott, who founded IGS in 2013 when he was in his twenties. “His background was trading with retailers and the big, traditional farms. He could see some of the pain that he was feeling then and the pain farmers would be feeling in the future. This was 10 years ago. He had a vision to do this, but it was my job to bring the technology together.

“About 18 months ago, we were approached by the James Hutton Institute to try and make small trees at scale. We proved that.” 

As mentioned, this concept is not new in farming, and it’s not even new in forestry.

Around the same time Dave and Henry were coming up with their idea, a similar trial was underway in Sweden. 

It did not go to plan. Around three quarters of the seedlings died; the idea was quickly binned. But it seems the Swedes were just a little too ahead of their time. 

“The technology has come on massively,” Dave says. “That includes the efficiency of the LED lights – they are cheaper to run – and the ability to control things at a very specific point. 

“Everything has previously been feasible in research. Now it is finally achievable on an industrial scale. We’re maybe not the first to attempt this kind of thing, but we are first to succeed at this scale. 

Dave Scott, the founder of IGS. (Image: FJ)

“We’re not trying to demolish the existing nursery industry, but elevate its success.” 

By now you might be wondering what the downsides are. Costs, for one. The towers – there are already plans to build two more on the site – come in at millions (although the specific price is not clear yet). Then there’s convincing cash-strapped ministers to invest in the kind of thing that requires a degree of imagination to see the benefits of. 

“I don’t care if we’re the first,” Kenny says. “Why should it matter? We’re lucky enough to be in a position where it might happen. The nursery trade is not awash with money, so many might decide it’s not something they can achieve. 

“But the notion of vertical farming is so full of potential. You can imagine one of these sitting in the Sahara, using tiny amounts of water to provide food for people. What’s wrong with that? Elon Musk, get on board!”