Trees are an integral part of the UK landscape, not only in the dense woodlands and forests of the countryside we perhaps most associate them with, but also in densely-populated urban environments, where they can improve air quality, increase biodiversity and alleviate poor mental health.

Traditionally, however, the planting of trees in metropolitan locales has been somewhat lacking. Now, though, the Tree Council (in partnership with Kent County Council) has trialled an innovative (and adapted) approach first pioneered by a Japanese botanist – the Miyawaki method. In this post, we’ll be delving into what exactly this method is, how it works, its benefits and more.

Jump to:

• What is the Miyawaki method?
• How does the Miyawaki method work?
• What are the Benefits of the Miyawaki method?
• Results from the Kent trial
• Can you replicate the Miyawaki method at home?

What is the Miyawaki method?

First detailed by Dr Akira Miyawaki back in the 1970s, the eponymous method is a model of woodland establishment (and management) that encourages the rapid regeneration of urban land through the dense planting of native trees in relatively small plots. In other words, it’s a faster way to create a forest, and said forest is typically a more resilient and better-performing parcel of land, from a biodiversity perspective, than forests generated conventionally.

Credit: BemanHerish

How does the Miyawaki method work?

The Miyawaki method is a complex, yet meticulously-conceived method of forest generation – heralded by the 1994 UNESCO Biodiversity Congress as exemplary – that hinges on several core tenets. These principles were taken and adapted for the Kent trial, and include:

Using native trees

Amongst the most important aspects of the Miyawaki method is the use of native trees and shrubs. Native plants, by their very nature, are inherently well-suited to planting in the chosen location, leading to more resilient plants, improved biodiversity and quicker forest generation (as native trees are already adapted to the location’s conditions, they need no time to adapt). In the Kent trial, trees like beech, birch, cherry, willow, rowan and crabapple.

Plant density

Density of planting is another foundational factor in the Miyawaki method. Three to five trees should be planted per square metre, the reason for which was outlined by the Tree Council in their case study: “The high density and wide diversity aimed to create competition between species and encourage the relationships that develop between plants in a healthy natural woodland.”

Keeping it natural

The urban forest should be able to sustain itself long-term (once established) without the need for external feeding. With that in mind, no chemicals or fertilisers should be used throughout the development of the plot.

What are the benefits of the Miyawaki method?

The advantages of the Miyawaki method (or something akin to it) are numerous; forest is established much more quickly, biodiversity (that’s both the quantity of flora and fauna, as well as the variety – i.e. a biodiverse environment features lots of various different species) sees a big uptick, and resilience to future stressors like drought and air pollution is greater. What’s not to like?

Preparing the soil

One of the key steps in any Miyawaki-style forest is ensuring that the soil has been properly prepared prior to planting. In this case, the top one metre of soil was excavated across the plot, helping to aerate the soil. Alongside this, mycorrhizal fungi was added to help the plants’ roots better establish.

Results from the Kent trial

Now, the moment you’ve all been waiting for – the results. Drumroll, please… Well, it’s all coming up roses (which, funnily enough, was one of the shrub species grown in the study) for the Tree Council and Kent County Council!

When compared with the control site, the Miyawaki site saw tree survival rates just shy of 80%, while the control produced survival rates of just 47%. Furthermore, the cost per tree (and cost per surviving tree) was significantly lower than for the control site; cost per planted tree in the Miyawaki plot was less than half of that of the control, while cost per surviving tree was a whopping 79% cheaper for the Miyawaki forest.

Is the method applicable for home gardens?

If you have a large garden, or even a relatively modest garden, there’s no reason why you can’t try and replicate a fast, Miyawaki-style forest for yourself. But here is probably a good time to mention one of the potential drawbacks of this method of forestry. It can be pretty expensive.

It doesn’t take a rocket scientist to work out that, if you’re putting more trees into the same amount of space, the bill is going to be higher. But there are some more cost-effective workarounds you can consider to save some money, including buying your trees in bulk as bare roots, and making sure you do the digging all in one go.

Even if you don’t want to go full Miyawaki, you can still follow some of the botanist’s guiding principles and create your own beautiful forest garden. Look to use native species in as multi-layered and random a way as possible, and give them a bit of Rootgrow while planting, then let nature do the rest.

Final thoughts

Hopefully, there’ll be more of these urban micro forests popping up, because they’re good for nature and good for communities, too. The more green space people have access to, the better! We’ll most definitely be keeping an eye out for similar future projects, but whilst you’re here, why not check out our grow guides for all your planting needs?