Miyawaki Forest

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Description

Similar names: Tiny forests, Fast growing forests, Urban forests, Potential natural vegetation

The Miyawaki method is a reforestation technique that entails the growing of a forest within a few decades – instead of centuries – by taking into account the succession of plants and plant diversity that naturally occurs in forests. This method was first conceptualised in Japan by Dr. Akira Miyawaki and has been successfully implemented in areas with relatively high rainfall rates such as India, Malaysia, and South America. However, it has also been successfully practised in other/locations/, such as the Mediterranean; the steppe zone of Jordan; and the Persian Gulf region.

This technique is particularly effective as it imitates the structure of a mature forest. It aims at recreating all the different levels of vegetation and combinations of species that would naturally occur in a native forest without human intervention – defined as “potential natural vegetation”. Practitioners must carefully select the right indigenous vegetation best adapted to local conditions, and they need to commit to watering and mulching the seedlings during the first years of implementation of the intervention. One of the advantages of using this technique is that it allows for the quick regrowth of a dense forest rich in biodiversity which can retain rainfall and create a cooling microclimate effect. Furthermore, the maintenance is comparatively low, as the forest becomes self-sufficient after 3 years.

NOTE: The implementation of this technique can be expensive as it requires a lot of seedlings for a relatively small area. However, it allows to obtain a fully functional forest in a short time, with minimal maintenance needed.

  • More vegetation
  • Improve soil
  • Prevents erosion
  • Run-off reduction

  • Before establishing the forest, it is essential to verify that the site has all the biophysical requirements for the growth of trees and that the selected area will not cause any societal conflicts.
  • For forests which are highly vulnerable to wildfires, this intervention should be applied with caution, taking into account the context of the specific forest. A less dense forest would be a better fit in those areas.
  • This intervention can be time consuming at the very beginning (preparing the soil, watering, weeding, mulching, transplanting of seedlings)
  • More successful if engaging the whole community
  • Need access to water in the initial years to water the seedlings
  • Expensive if seedlings, especially of good quality, are not available.

Steps of implementation

  1. Study the area and define the potential natural vegetation: identify native species found within about 20 km of the selected zone. A number between 50 and 100 different species is recommended. Such information can be gathered by asking local and indigenous peoples which tree species are naturally growing well in the area. The vegetation structure should start with the planting of fast-growing plants, followed by pairing these plants with perennial herbs and grasses, and finally, shrubs and trees of different heights. The minimum space needed to plant a Miyawaki forest is usually 92m2 for a dense forest in which about 250 saplings are planted. However, this can be as few as 12 m2 for a less dense forest.
  2. Rejuvenate the soil: trees need a lot of organic matter to grow, therefore, ensuring that the soil is well prepared for the intervention is a fundamentally important step. A pit should be dug, and the soil should be prepared by incorporating organic materials such as dead vegetation and manure. Sometimes, it is recommended to build a small hill with accumulated organic material (with a maximum slope of 30%), as this can imitate the increasing soil layer of a natural forest. 
  3. Planting: saplings that are up to 80cm high should be planted, and a standard density of 3 plants per square metre is usually recommended in order to imitate a natural forest. However, this has to be adapted to the requirements of your area; a good rule of thumb is to imitate the density of the natural vegetation already occurring in the area or ask a local expert. The planting of the seedlings can be facilitated, and the watering reduced, by using the Planting pits intervention; hence, small pits containing soil and manure in which the sapling is planted. 
  4. Mulching: After planting the trees, the ground should be covered with a thick layer of mulch which imitates fallen leaves on the forest floor. However, one should be cautious to never apply the mulch in direct contact with the seedling - especially in humid areas - as doing so can cause rotting of the young plant. Once the trees have matured enough, they will self-mulch the soil with fallen leaves. This helps to protect the soil from water evaporation, whilst providing the soil with fertilisers and preventing weed growth.
  5. Maintenance: during the first 3 years of implementation, the plants will require occasional weeding and watering. After this period, the forest should be dense enough to prevent weeds from growing and to retain enough water to be self-sufficient. 

The trees grow fast (3 ft or 1 m per year), with a survival rate of up to 90%, and have the capacity to capture more CO2 than monoculture plantations.

For tutorials and more details about the method of application please click here.

This intervention contributes to:

It is important to remember that the values differ consistently from country to country, mainly due to the cost of seedling production. 

Establishment cost About US $ 3-4 per sq ft of planting area (manure, seedlings, watering etc)
Labour time 3-year commitment (for maintenance), more intensive in the first year
Maintenance cost 0,- after 3 years

Cost estimation of an example based in India, where 3 months-old saplings are produced at a cost varying between US $ 0.1  and US $ 0.5 per plant (Source)

1. Implementation of the Mayawaki Method in India by SayTrees 

Description
The SayTrees project in India is a small initiative aspiring to increase the green cover of the country. Currently, they have planted 12 Mayawaki forests in cities and villages on more than 3 acres of total forest area. Altogether, 34 515 tree saplings are being planted to create dense Mayawaki forests which grow quickly and start being self-sufficient. Some other initiatives in India are the Afforest Institute and the Forest Creators

2. Tiny forest in Zaanstad, The Netherlands 

Description
A tiny forest was created in Zaanstad, The Netherlands, to better connect society, in particular children, and nature. The initiative is a part of a bigger project, which has the ultimate goal is to create 100 Tiny Forests in the Netherlands, which is expected to be achieved in stages. To monitor these as well, the experiences in this study were used to develop a method to work with volunteers to monitor biodiversity. For more tiny forest initiatives, please click here.

 

External Sources 

  • How to prepare the soil - please click here. It is important to evaluate if this method applies to your region before implementing it. 
  • Boomforest - An organisation devoted to the spread of the Mayawaki method 
  • For some examples of urban forests around the world, please click here and here.
  • Here you can find an extensive list of case studies where the Mayawaki forest has been implemented.

Guides 

Videos