Benefits of Microforests

Katarina Samurović

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In a world that annually loses 10 million hectares of forests to lodging and another 35 million to insect damage, creating new ones on a tiny scale may seem like a waste of time. However, microforests or Miyawaki forests are increasingly seen as powerful allies in the fight for saving biodiversity and tackling extreme climate disruption. That is especially true for already overheated and crowded urban areas.

The unique afforestation approach of microforest projects is to mimic the creation of natural forests but at warp speed. Instead of taking a century or more like in natural forest ecosystems, microforest strategies aim to create dense, diverse pioneer forests in just two to three decades.

Sounds too good to be true? Well, some experts think so – as we’ll discover later, not everyone is a fan of microforests.

What are Miyawaki forests?

Microforests, also known as Miyawaki forests, mini forests or pocket forests, are small-scale afforestation projects that, despite their limited size, aim to create dense, diverse, and rapidly growing native forest ecosystems. 


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Although you may think that the word “microforest” refers to any small forested area, in reality, the term is mainly used synonymously with Miyawaki forests. The connection is logical – most mini-forests today were developed based on the pioneering work of Japanese botanist Akira Miyawaki. The concept involves mimicking the soil structure, plant community structure, and biodiversity of natural local forests emerging in a condensed space. 

What defines microforests?

Several factors differentiate a microforest or Miyawaki forest from just any small forested space.

Dense planting of trees and shrubs

Microforests are densely planted with various native tree and shrub saplings and plant species, often at a rate of two to five per square meter. The high density is the key to rapid growth because plants compete for the light coming in only from above.

Miyawaki forests have multiple layers of vegetation

Miyawaki forests are multi-layered. Species to be grouped should belong to different forest stories – for example, a tall tree, a small tree, and a shrub. This way, we get a layered natural-type forest that supports various ecosystem functions.

A diagram with shrubs and trees planted together to explain a Miyawaki Forest.
Miyawaki forests contain a diversity of tree and shrub species that are densely planted to accelerate growth. Diagram: Caitlin Dempsey with images from Canva.

Soil remediation

Unlike average urban planting projects where young trees are simply laid down in the ground (perhaps with some basic amendments), Miyawaki forests demand major soil preparation. The planting soil needs to resemble that of a mature forest – rich in humus and slowly decaying organic matter, with excellent water retention properties. 

Unlike average urban planting projects where young trees are simply laid down in the soil (perhaps with some basic soil amendments), Miyawaki forests demand major soil work. The soil that the saplings are planted in needs to resemble mature forest soil – rich in humus and slowly decaying organic matter, with excellent soil retention properties. 

Native species

The plant species that form the micro or Miyawaki forests’ plant selection should include native species for the region in question. Although it’s often tempting to try imported species with desirable characteristics, native tree and shrub species are best adapted to local environmental conditions and also best suited to support local biodiversity.

These forests are designed to grow rapidly

Microforests grow at an accelerated rate compared to conventional forests and tree plantations. Relevant resources claim they grow 10 times faster and 30 times denser, reaching maturity in 20 to 30 years. In contrast, it can take decades or even centuries for natural forests to develop into rich ecosystems.

A photo realistic drawing of a small forest with different layers.
Microforests are characterized by a multi-layered forest with trees planted close together to encourage rapid growth of the understory. Photo realistic diagram created using Adobe Firefly.

Low maintenance

Miyawaki-type forests need maintenance in the form of watering, weeding, and mulching only for the first two to three years. Once they’re established, they become virtually maintenance-free and self-sustaining. No pruning is needed.

Compact size

Microforests can be created in small areas, making them suitable for dense urban settings, such as parking lots, schoolyards, or other compact spaces. In theory, a minimum space for a Miyawaki forest is a space of 4 by 3 meters (12 to 16 square meters, or 129 to 172 ft²). Some practitioners say a minimum total area of ​​70 m² is required if you want to create a feeling of a real mini-forest.

What are the benefits of microforests

Microforests offer many environmental benefits, local and beyond. 

Pocket forests have a cooling effect

One of the most significant physical benefits of Miyawaki forests in urban areas is their cooling effect. Miyawaki forests help decrease the urban heat island effect, which is especially significant during heat waves. Researchers have estimated that 30% larger tree cover could have prevented 40% of heat-related deaths in the sweltering European summer of 2015. 

A photograph of a concrete pathway through a sun dappled forest.
The presence of trees can make the urban environment 12 degrees Celsius (about 22 degrees Fahrenheit) cooler than its non-shaded surroundings. Photo: Caitlin Dempsey.

Other studies from various parts of the world consistently show that, on hot days, tree cover can make the urban environment 12 degrees Celsius cooler than its non-shaded surroundings. A notable Miyawaki urban afforestation project in Amman, Jordan, already has a noticeable cooling effect of around 14 degrees Celsius despite forests being only young.

Microforests have a rich biodiversity

Microforests often form surprisingly species-rich ecosystems, similar to the biodiversity of Ethiopia’s church forests. Besides native plants, it features fungi, invertebrates, birds, reptiles, and mammals. A return of the species extinct in a particular neighborhood is something enthusiasts commonly observe after a microforest is planted.

Dutch study recorded 943 species of plants and animals across 11 studied microforests in The Netherlands – 636 animal and 298 plant species, excluding the standard 40 species planted during the mini-forest formation. 

A great horned owl peers down from a tree.
Microforest offer refuge and habitat for a variety of native species. A great horned owl peers down from a tree. Photo: Caitlin Dempsey.

As James Godfrey-Faussett, a forest restoration specialist at the SUGi Pocket Forest project, explains, “Within a forest, biodiversity means balance, Birds control pests, insects pollinate plants, and beneficial fungi keep the trees healthy. Every organism has a role to play, and all these roles interact. And if you build a healthy, biodiverse habitat that can look after itself, it becomes self-sustaining. You can step away and let nature get to work.

Mini forests are sources of carbon sequestration

It’s common knowledge that trees suck up carbon dioxide from the air and build it into their biomass. Because tiny forest trees grow fast, consequently, they’re very good at sequestering carbon.

The Duch microforest data show that each mino-forest stores 127 kilograms of CO2, but once fully grown, each should be able to store around 250 kg. 

Miyawaki forests have a beneficial socio-economic impact

Miyawaki himself insisted that the local community needs to be a part of every Miyawaki project so they could connect to the forest that would be theirs to enjoy and take care of.

And the forest gives back. Relief from heat draws locals near the mini-forest, offering a pleasant space for socializing and community building. Japan is also the birthplace of the concept of “Shinrin-yoku” which is the practice of forest bathing to promote well-being and lowered stress levels.

In some areas, people are even willing to go the distance to visit – Miyawaki forests tend to become a local attraction. More people in the area means an inevitable boost for local businesses. 

A father and his daughter walking on a path through a forest.
Walking in a forest has many mental and physical health benefits. Photo: Caitlin Dempsey.

Other ways Miyawaki forests benefit our environment include combating air and noise pollutioncollecting rainwater and helping prevent flash floods, stabilizing water table levels, establishing wildlife corridors, promoting soil health, and providing excellent educational opportunities for students.

Microforest Criticism

Mircroforest benefits may sound too good to be true – and that’s precisely what many critics think.

“Irrational” tree mortality

High competition between the saplings results in high mortality as one Miyawaki forest continues to grow. Some estimations claim that only 15% of originally planted saplings can survive into the mature forest stage and that it just doesn’t make sense to invest resources into so many young trees that are eventually doomed. On the other hand, Miyawaki advocates say that young tree die-off is a natural process for cleared forest space regrowth and that dead plant material feeds the soil and attracts wildlife.

Micoforests can be costly to maintain

Although you may conclude otherwise the first time you hear these forests are “maintenance-free,” in reality, the Miyawaki method is expensive. That is mostly due to the soil building that precedes planting. All the soil amendments – from plant biomass to compost or manure to peat or coco peat – combined with machinery renting and consultation fees can make the expenses skyrocket, especially for larger projects. For example, just planting and soil amendments in Cambridge’s Danehy Park Miyawaki forest had cost $18,000, as the New York Times writes.

Incompatibility with local ecosystems

Despite insisting on local species, not all locations where Miyawaki forests are planted have naturally thick forests that grow in rich, moist soil. In some places where Miyawaki forests are popular, like India, many microforests seem misplaced. Instead of restoring open forest or scrubland ecosystems, organizations that do Miyawaki-style reforestation sometimes disregard the authentic natural environment and plant mini-forests “by the book” – but that don’t really match actual local ecosystems. 

Greenwashing

Perhaps the greatest issue with microforest planting stems from a potential narrative and not the forests themselves – because their creation can be easily used for greenwashing. By fostering a public image that mini-forests are some sort of environmental panacea solving everything from extinction to air pollution, they can be misused to justify cutting down old-growth forests or to cover up the environmental misdeeds of companies

Corporations that try to present themselves as “greener” through planting projects include those whose subcontractors actively participate in the deforestation of sensitive habitats, as well as oil companies that are causing large-scale environmental destruction by fueling climate change. 

The Final Verdict on Mini-Forests

People tend to have strong – and contrasting – opinions on popular phenomena, and Miyawaki forests are no exception. Amidst the storm, let’s try to be objective.

It is undeniable that Miyawaki-type forest ecosystems provide many benefits for local plant, animal, fungi, and human communities, as listed in this article. However, they are not a fit-for-all solution. It seems that they fit into regions where similar types of forests to those originally replicated by Miyawaki already exist – where hummus-rich soil and woody thickets are a natural occurrence. 

Still, we shouldn’t swap the “slow” rewilding and habitat restoration projects for lighting-fast growing forests. Other ecosystems vital to the stability and richness of our environment exist and deserve attention, funding, and, most importantly – conservation.

Another problem with the Miyawaki method is that it uses simple algorithms and mathematical calculations with a few elements to plan out and foster a very complex natural ecosystem. While experts who truly understand how these ecosystems work are likely to use it right, the popularity and approachability of the method make it easy for those who don’t have such deep understanding (and appreciation) to misuse it.

A view of the lower forest canopy and floor in a redwood forest.
Forests are complex ecosystems. Photo: Caitlin Dempsey, Henry Cowell Redwoods State Park.

Ecological gardeners and former microforest planters Fazal Rashid and Somil Daga emotionally write about what they witnessed in India: “(…) Many government agencies, NGOs, and hubris-filled youth (like our earlier selves) have latched onto [Miyawaki forests] as an easy way to make money and plant trees without needing to understand the nuances of ecology and biodiversity at all – and cause lots of damage in the process.”

The pair goes on to suggest the damage could be reversed “by slowing down and actually forming a connection with plants, landscape and local communities” but still ends in a pessimistic tone – “nobody seems to have the time for this, for such are the times we live in.

Like with most techniques and technologies, microforests aren’t inherently good or bad – it’s just a matter of how we utilize them. Miyawaki-type afforestation can indeed help local biodiversity and provide relief from increasing heat; likewise, they can be misused to put dense forest ecosystems where they don’t belong while covering up corporate environmental destruction. 

Two facts are clear: we need innovation like microforests to create a healthier environment in an increasingly urbanized world; however, we must remember that we cannot replace the perfect, already existing natural forests and other ecosystems that need our protection.

Resources

The Study

Miyawaki, A. (1999). Creative Ecology: Restoration of Native Forests by Native Trees. Plant Biotechnology. https://doi.org/10.5511/plantbiotechnology.16.15

Articles

Buckley, Clara. Tiny Forests With Big Benefits. The New York Times. 24 August 2023

Chaurdon, Jean-Baptiste. The Key Steps of the Miyawaki method to plant a mini-forest. 12 July 2023

Interim results Tiny Forests 2017-2020. Wageningen Environmental Research (WENR; in Dutsch)

Giseburt, Annelise. Miyawaki forests are a global sensation, but not everyone’s sold on them. Mongabay, 21 June 2023

Rashid, Fazal; Daga, Somil. How Mr Miyawaki Broke My Heart. Science, The Wire. 25 April 2023

Oldham, Olivia. Amid Mounting Climate Threats, Danehy Park’s Miyawaki Forest Puts Down Roots. The Harward Crimson Magazine. 22 September 2022

Tayseer, Mohammad; Millan Laura. Fast-Growing Mini Forests Help Cool Down a Desert City. Bloomberg. 23 August 2023

The Miyawaki Method For Creating Forests. SUGi, 19 October 2021

The Lancet: Planting more trees could decrease deaths from higher summer temperatures in cities by a third, modelling study suggests. Phys.org. 31 January 2023

Tiny Forests Improve Biodiversity in Urban Areas. European Platform Urban Greening. 1 February 2021

World losing forests the size of Iceland – every year. UNRIC. 17 March 2023

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About the author
Katarina Samurović
Katarina Samurović is an environmental analyst and a freelance science writer. She has a special interest in biodiversity, ecoclimatology, biogeography, trees, and insects.