As recently stated in our article on reforestation and afforestation, the Miyawaki method is one strategy that can be used for forest creation. Here, we will investigate this approach in greater depth.
What Is the Miyawaki Forest Creation Method?
The Miyawaki Forest Creation Method is used to create new, biodiverse, and multi-layered native forests.
It is characterised by a choice of species based on ‘potential native vegetation’ (PNV), which is densely planted according to deep ecological knowledge and expert advice for best practice, in relation to the local environment.
This approach to tree-planting, based on the work of Akira Miyawaki, can accelerate the creation of biodiverse and ecologically functioning forests or woodland on land where forest cover has been lost due to agriculture or construction.
Whereas native forests typically take 150 to 200 years to grow, using this method, we can create dense native forests in just 20 to 30 years, at which point they may already reach equal or greater biodiversity to natural forest or woodland in the same area.
Who is Akira Miyawaki?
Since this method is named after its creator, you may be interested in learning a little more about the man for whom this method is named.
Dr Akira Miyawaki is a Blue Planet Award-winning Japanese botanist and plant ecology specialist with a particular interest in phytosociology: the study of plants’ interaction within communities.
Having studied ecology and completed his PhD, he headed to Germany to study with the phytosociologist Reinhold Tüxen, from whom he learned the principles of potential natural vegetation. Upon returning, he began to apply those principles to the Japanese landscape.
There, he studied the fragments of ancient forest around temples and shrines, the species composing them, and the distinct layering of species within these ecosystems. He noted that these forest fragments contained native species rather than the introduced species which dominated other local forests, and categorised the forest layers: the canopy, the tree layer, the sub-tree layer, and the shrub layer, with herbaceous vegetation below.
From what he had observed, Miyawaki came up with his new method for planting forests, using knowledge of native vegetation studies and how these species would grow and interact with one another to create a dynamic forest ecosystem.
What is Potential Native Vegetation?
Potential natural vegetation (PNV) describes vegetation that would naturally be present on a particular site without human intervention or a hazard event. This concept was developed by Tüxen in the 1950s, expanding on the previous concept of climax vegetation.
Maps of potential natural vegetation are now used around the world to find the optimal plants for use in conservation, renaturation, rewilding, and reforestation and afforestation.
Finding the potential natural vegetation for a particular site is a much-studied topic. However, discovering the PNV is not always as easy as it may seem; Miyawaki himself learned that what were long supposed to be ‘native species’ had in fact been introduced over a thousand years earlier. He also found that when truly original species were introduced, they could provide better results even than species introduced long ago.
The Application of the Miyawaki Method
Since beginning in Japan, Miyawaki’s method has spread around the world. From rehabilitated rainforests in South East Asia, China, and South America, Miyawaki has gone on to plant over 40 million trees across 15 countries.
Some of those continuing his legacy are located in India. Notable among them is Shubhendu Sharma, who is considered by some to be an heir apparent of this forest creation movement.
In 2009, Miyawaki gave a presentation at a Toyota factory around which he had come to apply his method. Sharma, who worked there as an industrial engineer, was captivated.. He volunteered to help plant more than 32,000 native trees in the industrial landscape, and in the process, his life changed. In 2011, he applied the method in his own back garden, before leaving his job and former life to open Afforestt, a forest production company.
Using the Miyawaki method, this company has since gone on to plant over 450,000 trees in 144 tiny, fast-growing forests in 50 cities around the world.
Though not alone in following this method, Sharma stands out because, as well as following Miyawaki’s teachings, he has also sought to synthesise them by drawing on his background as an engineer. Sharma has turned the method into a set of assembly-line instructions, which can easily be followed by those who wish to adopt this method around the world.
Though Afforestt offers services in forest creation, consultation, and training, Sharma also makes his guides and instructions freely available to all. Through his work, the Miyawaki method has spread across India, and to Europe and elsewhere.
Miyawaki Forest Creation in Europe
Though it took some time for the West to become aware of the Miyawaki method, it has now been adopted across Europe – predominantly in the creation of urban mini-forest sites.
In the Netherlands, for example, since 2015, IVN Nature Education has helped cities and households to plant 100 forests using the Miyawaki method. The company are on track to double the number of forests created by 2022.
In 2016, Urban Forest‘s Belgian founder began planting Miyawaki-style forests, and the company has also created a useful summary of scientific research on the creation of Miyawaki forests.
There are also examples in France, the UK, and elsewhere. This year, in East London, volunteers planted the largest Miyawaki forest in Europe, as a ‘Forest of Thanks’ dedicated to NHS and other key workers in England.
Creating a Forest Using the Miyawaki Method
So, it’s time to get down to the details. How exactly can you follow this process to create your own forest? Below, we will walk you through the typical steps.
Step One: Survey Local Original Forest/Woodland Fragments
Forests can teach us a lot – this is especially true of old-growth forests and ancient woodlands, or secondary forests which have persisted naturally for a very long time.
Here we may encounter our first stumbling block, since local ecosystems which truly reflect the original native vegetation of a particular bioregion and ecotone (the transitional region between two biological communities) may be difficult or even impossible to find. Whether recently or in ancient times, the forests in your area will almost inevitably have been shaped by human interference, to some degree.
However, by both observing and studying local forest/woodland, and by investigating the historical evolution of the site and area, it is possible to learn a lot about both the potential natural vegetation of the area, and the ways that the plants within the systems interact with one another.
Step Two: Identify the Potential Native Vegetation Tree Species
Forests and woodlands are most frequently defined by their predominant tree species. Therefore, deciding which native tree species should define the forest you wish to create is a good starting point.
Typically, the dominant native tree species should make up around 25% of the system as a whole, with more minor species from the same ecosystem accounting for the rest.
Step Three: Determine the Forest Community Structure and Select Under-Storey Species
Remember, in a Miyawaki forest, there are four layers: the canopy trees, sub-canopy trees, shrubs, and plants of the herbaceous layer of the forest floor. (This differs from the methods of permaculture or food forest creation, which identify seven layers: canopy trees, sub-canopy trees, shrubs, climbers, taller herbaceous plants, ground-cover plants, and the rhizosphere (below soil level).)
However, both approaches try to create ecosystems which mimic the complex web of interactions between plants which occurs in a natural forest system. In selecting species for a new forest, it is important to look closely at how the different plants in the ecosystem you wish to mimic interact with one another: which species grow together, and why.
Careful analysis will give you a list of native plant species which, over time, when planted together, will become not a plantation but an ecologically functioning forest – a forest that can thrive without human intervention.
Paying attention to both native forests/woodlands and to experts in local plant ecology will allow you to identify polycultures of plants to use in your new forest.
Step Four: Conduct Site Analysis and Soil Surveys
Even if particular trees and other native plants thrive in nearby forest fragments, they will not necessarily do so on the site chosen for afforestation.
As well as closely observing native forests or woodland, it is also important to observe and analyse the site itself. Sunlight and shade, wind and water, terrain and slope, climate, microclimate, and geology: all play a role in determining which species will thrive on the site.
However, the next key step within the Miyawaki forest creation process is to look at the soil. It is important to identify the soil type and undertake soil analysis to determine its properties, such as composition and fertility, drainage speed, pH, etc.
This analysis will affect the choice of native species to plant, and dictate how the soil should be improved before planting.
Step Five: Obtain Seeds, Seedlings, or Saplings
Once you have undertaken the complex work of identifying the PNV for your bioregion and location, and the appropriate plants, and have created a thriving polyculture for an ecologically functioning forest, you can source your seeds, seedlings, or saplings.
The cheapest option is to grow all trees and plants from seed, and potentially also using divisions or cuttings from an existing forest. However, this is not always possible or practicable at the necessary scale. This would also require somewhere to be available for seed propagation and for use as a plant nursery.
The next best option is to obtain trees and other plants from a local plant nursery, if one exists in your area. Local plant nurseries are also likely to be knowledgeable about the needs of specific plants and how to care for them.
Something to note is to avoid purchasing plants grown or propagated too far from the site. The more local, the better, since locally grown plants will likely be best suited to the growing conditions on the afforestation site.
Remember, whether or not you are growing from seed and propagating your own plants, you will need to consider caring for them until they are planted: where they grow until this point, and general care like watering. Care needs will differ depending on the site of the afforestation; in hotter areas, for example, shading can be crucial for the plants’ early health.
Step Six: Improve Soil/Add Mulch
The preceding steps and preparation will have taught you how to provide a healthy growing environment for your plants. Soil is crucial to the formation of a new forest, and the next step of the Miyawaki method focuses on improving and preparing the soil of the site prior to planting.
When soil surveys were undertaken, these should have identified any necessary amendments, such as organic soil improvers may be used.
Further amendments will be made by layering (top dressing) the site with a layer of organic mulch. This biodegradable material, sourced locally, is designed to replicate forest-floor humus and leaf litter, which provides nutrients and some protection to the plants growing within it.
Materials used will differ depending on local availability, but alternative options such as vermicompost, rice husk, coir, straw, etc, are also often used. Organic mulches increase fertility and improve soil structure over time, protecting it, conserving moisture, and suppressing weeds and unwanted vegetation.
A mulch of forest materials (woody material, bark, wood chips, dried leaves, etc) will also encourage the soil biota to flourish – especially the fungi which are such an integral part of a forest ecosystem. In fact, mycorrhizal fungi are sometimes added in the Miyawaki method, since these help tree and shrub growth and, in some instances, may increase resistance to pests, disease and adverse environmental conditions, and improve survival rates.
Step Seven: Plant Selected Forest Species
Creation of a Miyawaki forest differs most greatly from other tree-planting strategies at this stage.
The species selected are planted at random, extremely densely: 20,000 to 30,000 per hectare instead of a more common 1,000 per hectare. Under the Miyawaki method, trees are planted in three to four clusters per square metre.
Such dense planting causes the trees and other plants to compete fiercely for space and resources, so that the system itself finds the balance and the fittest survive.
In the face of such stiff competition, the interaction between different plants and the symbiosis between them becomes even more important. Those that can co-operate thrive; those that cannot quickly lose out.
This competition also accounts for plants’ remarkably swift rate of growth within the Miyawaki system.
Maintaining a New Miyawaki Forest
Once planted, the forest should be entirely wild and self-sustaining within around three years.
However, it is crucial to care for the trees and other plants until that point, when the system becomes established. Consider water needs, and water well during the first couple of growing seasons.
This system also requires a certain level of commitment, since the site should be monitored and weeded regularly until it fills out and becomes self-sustaining.
Aside from watering and weeding, however, the site is maintenance-free even during establishment; you have provided the ingredients, and simply need to let nature take its course.
Why Adopt the Miyawaki Method?
Here are just some reasons why this method is highly regarded:
Speed of Establishment
The main benefit of the Miyawaki method is that it allows the creation of a stable and ecologically functioning forest in far less time than traditional approaches.
This increased speed of establishment means that the forest will be able to sequester carbon and deliver its other ecosystem benefits far sooner – and speed is crucial as we seek to remedy the harm humanity has done, and to mitigate and adapt to anthropocentric climate change.
Trees and other vegetation in a Miyawaki forest sequester more carbon than other types of new forest that are created, not only due to speed of establishment, but also because of density of planting. There are many more trees in one of these planting schemes than in standard tree-planting/afforestation schemes, perhaps as many as 30 times more.
Works Everywhere: Success Where Other Schemes Have Failed
Using potential native vegetation to determine the right plants for the right places also means that this method has succeeded in forest creation where other methods have failed. Examples include successful implementation in arid Mediterranean climate zones, where tree survival rates have been high compared to other afforestation methods.
Unfortunately, reforestation and afforestation approaches have not all met with success, and some have been abject failures. China’s Great Green Wall initiative, where up to 85% of the plantings may fail, 11 million dead trees in Turkey, and numerous challenges for Africa’s Green Wall, are just some examples which teach valuable lessons about ecosystem restoration.
Though the Miyawaki method could succeed where other schemes have failed, in some regions, alternative approaches may better suit the needs of people and of the planet.
Researchers have monitored newly planted Miyawaki forests and concluded that they increase biodiversity compared to nearby reference forests.
This high biodiversity is due to the forests’ young age and openness, as well as to the multiple-species, layered approach. In some cases, biodiversity has been found to be up to 18 times higher than in non-Miyawaki forests.
However, while impressive, it can be argued that more research is needed to determine how biodiversity will alter as the newly planted forests evolve.
Sustainable City Improvement
The method has been particularly successful in creating urban micro-forests, which bring a wide range of benefits, including:
- Temperature reduction, helping to counteract the heat island effect (due to manmade structures absorbing and re-emitting the sun’s heat), and reduce pest density
- Improvement of air quality
- Provision of amenity and fantastic benefits for the well-being of city dwellers.
The relative ease of this type of afforestation, and the communal component of doing so, can also boost community cohesion and help city groups come together to improve their environment and combat global crises.
It is in this arena, perhaps, that the Miyawaki method is most interesting and beneficial. Simplifying the process and allowing new forest ecosystems to quickly re-green urban environments could be key to creating the urgently needed sustainable cities of the future.
Miyawaki forests have also been successful in tackling a range of specific issues, in specific locations. For example, they have been shown to be beneficial in slope management and erosion control. Effective revegetation techniques like this can stabilise soil and manage mine dumps of mounded-up waste.
In specific locations, speedy forest creation can also help communities to adapt to climate change, and to cope with increasingly prevalent extreme weather conditions and events. For example, Akira Miyawaki has been involved in planting along the Japanese coastline to protect from tsunamis.
These are just some examples of the many reasons for increasing interest in this method of forest creation.
Criticisms and Shortcomings of the Miyawaki Method
Though this method of forest creation undoubtedly shows promise, and brings a huge range of benefits, it is important to be realistic about what it can provide.
Problems with Potential Natural Vegetation
Firstly, there has been some criticism of the concept of potential natural vegetation which underpins this method. There are some methodological problems associated with the definition of this term, and issues relating to ecosystem dynamics.
We need to acknowledge, especially in areas with long-term human history, that interpretations need to be cautious, and there may often be limitations to available data. Even those who accept and use the concept understand and acknowledge its limitations.
All Trees Are the Same Age
Another potential shortcoming is that the Miyawaki method generates forests where all the trees and other species are of the same age. This is a major departure from a truly natural forest ecosystem, where species composition and the forest ecosystem varies significantly over time.
In nature, a process of succession takes place: first, pioneer species colonise a site. These are then often shaded out and replaced by other species. As the forest matures and the trees go through their life-cycles, its ecology and biodiversity alters in a range of complex ways.
Though Miyawaki forests share many of the benefits of a true natural forest during early stages of growth, more research must be done to evaluate their long term performance. This may have impacts in future, as the trees naturally age and die off at the same rate – unlike those in forests evolving more naturally,.
Standing and fallen deadwood can be an important factor in the ecology of old-growth forests and how they evolve over time. How will Miyawaki forests evolve without a natural combination of trees at different stages in their life-cycles? Without the aged species in an old-growth forest or ancient woodland, how will this impact long term regrowth?
We certainly do not have all the answers; more research is required to assess the impact of these new forests, in both the short and long terms.
Not a Replacement for Truly Natural Forests
While they can provide many benefits, Miyawaki forests cannot be viewed as like-for-like replacements for old-growth or ancient forests and woodland.
However, this is true of all types of new forest. However, though not replacements for ancient-tree ecosystems, they do have great potential to improve sites where no forest or woodland remains, due to agriculture, construction, or other human activities.
Additional Preliminary Steps May Be Required for Some Sites
This method, unlike some other approaches, does not deal with the idea that additional remediation steps may be required before native vegetation can thrive. (Bioremediation through the use of plants/fungi, etc, can be an interesting area to explore where forest creation focuses on polluted city sites.)
It may be necessary to consider how our changing climate has impacted the area in question, and whether this means that further steps (for water availability, etc) are required. The permaculture approach to forest creation, for example, takes into account the idea that human intervention in the landscape (such as earthworks) may be necessary before new forests can emerge and thrive.)
Neither of these things, however, means that the Miyawaki method won’t work, simply that other options may have to be considered first.
Expense and Complexity
It is also noteworthy that Miyawaki forest creation, with its demand for such high density tree-planting, can be more expensive to implement than other afforestation approaches.
Given its complex demands of selecting the right species and correctly amending the soil, it may not be the easiest method for the lay-person to adopt. Therefore, employing experts during the initial stages may be beneficial in many cases.
This method shows immense potential in quickly increasing forest cover and tackling some of the major crises we face (such as climate change and biodiversity losses). It is particularly effective on city sites, and for tackling specific issues in a timely and comprehensive way.
However, while we should all be planting trees, creating new, fully-functioning forest ecosystems is a complex topic which requires further research, and demands immense care to be taken over exactly where and how it is achieved. If you are interested in doing so, extensive research and consultation with experts on the topic is typically the best way to proceed.