Miyawaki method put to the test in Lake District rewilding project

FORESTRY as a pursuit is ill-suited to the impatient. Professional foresters get used to thinking in terms of decades rather than years. Anyone thinking of undertaking a broadleaf planting project must typically get comfortable with the idea they may not be around to see it reach full maturity.

This can be frustrating, especially if your goals are to maximise carbon sequestration and recreate habitats for biodiversity and wildlife. While the appetite to increase tree planting to combat climate change and environmental destruction is undoubtedly growing, there is a sense that much more could be achieved if we could only get quicker results.

However, there is one approach which could change the way rewilding is done in the UK, maximising funds and delivering thriving woodland in far less time. And last year, a habitat–restoration project in Cumbria put it to the test on a grand scale.

Ten years ago, ecologist Sally Phillips started a company called Chimney Sheep, selling an eco-friendly chimney draught excluder made of felted wool. Twenty per cent of the profits have gone to her community interest company Buy Land Plant Trees, which purchases land deemed agriculturally useless and turns it into woodland.

Its second site, a 13-acre field near Bassenthwaite, was bought late in 2020.

“It had been left for a decade or so because, agriculturally, it’s not very productive,” said Sally. “The drainage is poor; it’s pretty wet at all times of the year. It wasn’t really suitable for grazing, hay or anything like that. It was basically just left, so I bought it with a view to creating a habitat–restoration project.”

She got in touch with Cumbria Woodlands, which helped put together a proposal for a grant from the United Utilities Tree Fund. The initial proposal was for planting 5,000 trees, but Sally wanted more, so approached her friend and experienced tree planter Neil Watson to ask what more they could do. He suggested the Miyawaki method.

Created by Japanese botanist Dr Akira Miyawaki, the Miyawaki method helps to create forest quickly by planting trees in dense clusters to amplify the natural growth process.

By using a mix of species with varied canopy levels and close planting, the trees support each other, providing shelter and protection from predators. The trees planted by this method grow much faster, jump-starting the forest–creation process and capturing more carbon. Higher biodiversity has been recorded in Miyawaki forests than in neighbouring woodland. Used around the world, predominantly in urban areas where soil is depleted, it has come to be regarded as one of the most effective tree-planting methods for creating forest cover quickly on degraded land.

“Sally didn’t want tubes and stakes using plastic and chemicals,” said Neil. “So we had conversations about different approaches and worked out that for the cost of 5,000 trees with tubes and stakes she could get 20,000 trees in the Miyawaki style. This means they’re planted without any protection, in the traditional sense, but hopefully other factors in their planting mean we have a relatively high survival rate. Even if we had a 50 per cent survival rate, which is probably the worst-case scenario, we would still be left with significantly more trees than with tube and stake.

By April, trees were beginning to bud.

“Plus, that 50 per cent will be producing seeds sooner, which fits with the whole rewilding idea, because the seed stock is not falling inside the tube. It’s being spread. So even if that 50 per cent, 10 years down the line, starts failing, they’re still producing seeds, still rewilding.”

After doing a lot of research, Neil and Sally went back to Cumbria Woodlands with a proposal to use the Miyawaki method and found they were interested in giving it a go.

“We’re always interested in new methods and new ways of doing things,” said associate and forestry consultant Carrie Hedges. “The Miyawaki method was something I really liked the idea of trialling, because it mimics the way trees are produced in nature. The majority of our native trees will grow naturally in clusters, which provides protection and support. The surprising thing is we haven’t tried it before.”

With the plan approved and funding in place, work could begin to prepare the ground for planting.

Neil said: “The traditional Miyawaki method is quite laborious, bulldozing the land and bringing in fresh soil. Our land was quite fertile, so there was no need for that. Instead, we just pre-screefed the blocks with a quad harrow about five months in advance of planting, to get all the vegetation out of the way.

“That gave us a mulch layer and opened up the ground so predator bird species could take care of the voles, rabbits and hares. We brought in a local stalker to bring the deer population down. We also put some owl boxes up and massively thorned the edge with hawthorn, blackthorn and other hedge species to develop a boundary layer and stop any deer wandering through the block.”

When the time came for planting, a small team planted species in clusters of five or seven, with roughly 40 cm between each tree and mulch mats laid down to provide extra nutrients. 

Over 25,000 trees were planted, with a mix of 39 different species to future-proof against disease, including two kinds of oak, four elder, six willow, multiple hedge species and sycamore – and all achieved relatively painlessly.

“Regarding the planting team, we had one person on species organisation and two or three people picking up a bundle and sticking them in the ground, and that was it,” said Neil. “In terms of planting ease, there was no bagging up trees or chemical spraying. All anyone had to bring was a spade. 

“The mulch mats will stay on the trees three years and start rotting down. They should keep any vegetation at bay until the trees are well established. And they keep the ground quite flat, so if any voles are a problem, the predator species can see them and get them. Other projects normally mulch with straw, which needs a lot of aftercare and has to be replaced. Using the mats is more expensive, but it’s one hit and done, so it’s a long-term cost saving.”

Planting got underway in March.

The low-maintenance aspect of the Miyawaki method was an especially appealing one where Chimney Sheep’s site was concerned. Already difficult to access, the hope is that it becomes home to a fully wild, natural-looking habitat, free from any form of management. A few months on from planting, things are looking good.

Neil said: “Initially, I think we will have some deer damage and, like any planting, there will be some transfer shock and we will lose some in the first year. But down the line they will sort themselves out and I’m hoping in just five years’ time we should have a nice young woodland.”

While it’s still incredibly rare to see the method used on this kind of scale in the UK, Neil believes it has tremendous potential.

He said: “It is just beginning to become as well known as it should be. In terms of costs, the health and safety of planters and from an environmental perspective, the benefits are massive. I think it’s win-win all round. The folk with negative views of the style are too ingrained in using tubes and stakes. But even if you’re doing a small block, you can plant five times the number of trees for the same cost. And even if you get 50 per cent loss, you’re still better off. And the chance of having 50 per cent loss, if you’ve done all the proper preparation, is very low. With commercial stock it’s different, but for rewilding projects, I think it has massive potential.”

For Sally, a technique that promised to produce a healthy woodland in just five or ten years was too good to ignore.

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“I’m in my fifties, so I want results fast and the Miyawaki method promises quick results,” she said. “It is based on the premise that there will be an attrition rate and some trees won’t survive, which does make some people uncomfortable, but it’s a process that mimics nature. And there are other costs and problems associated with more traditional methods of planting.

“Trees are always a long-term project, but if your focus is on habitat creation and restoring native woodland, I think it’s a great way to achieve your goals more quickly and easily.”       

www.chimneysheep.co.uk