In a world that loses 10 million hectares of forest to logging each year and another 35 million hectares to insect damage, creating new forests on a tiny scale may seem insignificant. Yet microforests, also known as Miyawaki forests, are increasingly being recognized as a valuable tool for supporting biodiversity and helping cities adapt to climate change. Their benefits may be especially important in densely populated urban areas that are already experiencing rising temperatures.
The goal of a microforest is to recreate the structure and ecological functions of a natural forest in a fraction of the time. While natural forests may take a century or more to develop, microforest projects aim to establish dense, diverse forest ecosystems within just a few decades.
Sounds too good to be true? Some experts think so. While supporters see microforests as an innovative tool for restoring nature in urban environments, critics argue that the benefits are sometimes overstated and that the approach is not appropriate in every setting.
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.
While the term “microforest” may seem to describe any small forested area, it is most commonly used to refer to Miyawaki forests. The connection is logical – most mini-forests today were developed based on the pioneering work of Japanese botanist Akira Miyawaki. The concept aims to recreate the soil conditions, vegetation structure, and biodiversity of native forests within a much smaller area.
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 planting density encourages rapid growth as plants compete for available sunlight.
Miyawaki forests have multiple layers of vegetation
Miyawaki forests are multi-layered. The selected species should represent different forest layers, such as canopy trees, understory trees, and shrubs. This creates a layered forest structure that supports a variety of ecosystem functions.
Soil remediation
Unlike many urban tree planting projects, Miyawaki forests require extensive soil preparation before planting begins. The soil is amended to resemble that of a mature forest, rich in humus and organic matter with good water retention and aeration. This intensive preparation is considered one of the key factors behind the rapid growth associated with the Miyawaki method.
Native species
The species selected for a microforest should be native to the region. 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. Advocates of the Miyawaki method often claim these forests can grow several times faster than conventional tree plantings because of dense spacing, intensive soil preparation, and the use of native species. Growth rates vary by climate, soil conditions, and species selection, but many projects report reaching a forest-like structure within two to three decades.
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 Miyawaki forest can be established in an area as small as 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?
Despite their small size, microforests can have an outsized impact on urban environments. From cooling city streets and supporting wildlife to improving air quality and creating spaces for people to connect with nature, these compact forests provide a surprising range of benefits.
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.
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 develop into surprisingly species-rich ecosystems, similar to the biodiversity of Ethiopia’s church forests. In addition to native plants, they can support fungi, invertebrates, birds, reptiles, and mammals. Enthusiasts often report the return of species that had previously disappeared from highly urbanized neighborhoods after a microforest is established.
A Dutch study recorded 943 species of plants and animals across 11 microforests in the Netherlands, including 636 animal species and 298 plant species. That total excludes the species originally planted during the creation of the microforests
In urban landscapes, microforests can also function as habitat stepping stones. Although they are too small to replace large natural areas, they can provide shelter, food sources, and resting habitat for birds, pollinators, and other wildlife moving between larger patches of green space.
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
Trees absorb carbon dioxide from the atmosphere and store it in their biomass. Because the trees in microforests grow rapidly, these forests can be effective at sequestering carbon. The Dutch microforest data show that each mini-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.
These forests can also provide benefits to the surrounding community. 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. In some communities, successful microforests have become local destinations that encourage residents to spend more time in nearby parks and public spaces.
Other ways Miyawaki forests benefit our environment include combating air and noise pollution, collecting rainwater and helping prevent flash floods, stabilizing water table levels, establishing wildlife corridors, promoting soil health, and providing excellent educational opportunities for students.
Criticisms of microforests
While microforests have attracted widespread attention for their environmental benefits, the Miyawaki method has also generated criticism from ecologists, restoration practitioners, and urban forestry experts. Concerns range from cost and long-term survival rates to whether these forests are always appropriate for local ecosystems.
“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.
Microforests can be costly to establish
Despite their reputation as “maintenance-free” forests, Miyawaki projects can be expensive to establish. Much of the cost comes from intensive soil preparation, site design, and the large number of saplings planted in a relatively small area.
Much of that cost comes from the extensive soil preparation required before planting begins. 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 often contrasting opinions about environmental trends, and Miyawaki forests are no exception.
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. Microforests appear to work best where the planting design reflects the region’s natural forest ecology rather than applying a standardized formula. In areas where forests are not the dominant native ecosystem, other forms of habitat restoration may be more appropriate.
Still, we shouldn’t swap the “slow” rewilding and habitat restoration projects for lightning-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.
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 a matter of how they are used. Miyawaki-style afforestation can support local biodiversity and help reduce the effects of urban heat, but it can also be misapplied in places where dense forests are not the natural ecosystem or used to distract from larger environmental harms.
The growing interest in microforests reflects the search for new ways to make cities greener and more resilient. However, they are not a substitute for protecting and restoring the natural forests, grasslands, wetlands, and other ecosystems that already sustain biodiversity and ecological processes.
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 Dutch)
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 Harvard 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
