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What is the science behind Miyawaki forests?

rees play a pivotal role in maintaining the health of the ecosystem, although, it seems like humans are ignorant of this fact. Trees have been mercilessly cut down in the name of ‘development’ which has repercussions like soil erosion, lowering of the water table, silting, desertification. This has led to deeper implications including food crises, water shortages, health crises, loss of livelihood, and climate change. Afforestation could help to reverse this damage. But are planting trees enough? Is all the green really ‘green’? While planting trees is a great practice, not all trees will give the same advantages. Some end up being ornamental pieces that don’t support local biodiversity. Some introduced foreign species tend to dominate and threaten the existence of native species. There is a solution to provide a shade of greenery that serves its purpose well. It is gaining much popularity and is called the Miyawaki forest method.

What is the Miyawaki Forest Method?

The Miyawaki forest method was pioneered in the 1980s by Dr. Akira Miyawaki, a Japanese botanist and professor. He went on to receive the prestigious Blue Planet Prize in 2006 for developing this technique and for his other contributions to ecology. The conception of the method was inspired by the Japanese sacred forests or ‘chinju-no-mori’. These indigenous forests are found around Shinto shrines and cemeteries, protected due to their cultural value. His interest in allelopathy and the complementarity of species in natural forests further catalyzed this technique. Allelopathy is a survival mechanism in plants that allows them to compete with others. Plants are capable of releasing chemicals to stunt the growth of neighboring plants, bacteria and weeds. Plant species also complement other plants. The plants grow better when they grow together. This knowledge was applied to the Miyawaki technique. By studying local plant ecology, species that have key roles and complementary roles in the tree community are planted. These species are then supported by a variety of accompanying species.

Like many things, this technique found inspiration in nature! This plantation method imitates the structure of natural forests with 20 to 50 native species. The end result is a multi-layered forest consisting of shrubs, sub-trees, trees, and canopy trees. A complete forest is ready in a short period of 20–30 years. The Miyawaki forest grows 10 times faster and 30 times denser than a natural forest. The trick lies in the proximity of the saplings with 3 to 5 saplings per meter square. The proximity pushes the plants to compete with each other. This helps begin phytosociological relations between different species and allows them to grow faster. The saplings turn into a self-sustaining forest in three years. It is maintenance-free after the third year. This shouldn’t be very surprising because trees do grow on their own in forests without any human intervention.

How to grow your own Miyawaki forest?

  • A Miyawaki forest can be grown in an area as small as 100 square feet. Space should be at least 3 or 4 meters wide. The area should get a minimum of 8 hours of sunlight.
  • An intense survey is conducted to identify native species and the distribution pattern of trees in the local area and existing natural forests.
  • The next step is the identification and collection of seeds/saplings of indigenous trees in the region and in a similar geo-climatic context.
  • A soil survey is done to check the pH value of the soil. Based on the test, enrichments are chosen to best suit the soil.
  • The topsoil needs to be recovered to a depth of 20 to 30 cm, to fasten the soil evolution process.
  • Perforator material like biomass, rice husk, or coconut shells is used to create the ideal environment for growth. Water retainers like cocopeat are added to retain moisture in the soil for a longer duration.
  • Cow dung, manure, or vermicompost add further nourishment.
  • Saplings of the height of 60–80 cm are considered ready to be planted.
  • Species are planted at a distance of 60 cm from each other. Care should be taken so that no two species are placed together.
  • A thick layer of 5–7 inch mulch is put on the topsoil to prevent water evaporation.
  • The saplings are supported with sticks to allow them to grow upright.
  • The forest needs to be watered daily for the first two years. Water accumulation around the saplings should be avoided.
  • A close inspection of the forest is done to remove weeds and monitor plant growth.
  • The forest may have a high initial cost. The cost depends on the climate, soil type and, plant species.

Native trees and multi-layered forests

Each organism holds its place in nature and depends on its complex relationships with other organisms. Native trees have gone through years of evolution to adapt to the region. Insects, birds, and mammals have co-evolved with them. These trees require low maintenance and less water. They also support endemic species that are very unique to that region and found nowhere else. These trees act as windbreaks and are resilient in times of natural disasters. They can grow deep roots to tap water from the water table at lower depths and withstand droughts.

A forest can be divided into four layers-shrubs that grow up to 6 feet (8 to 12%), sub-tree that grow up to 25 feet (25 to 30%), trees that reach up to 40 feet (40 to 50%), and canopy trees that grow taller than 40 feet (15 to 20%). Emergent trees are the tallest trees in the forest that grow beyond the canopy layer. They provide habitat to birds of prey like eagles, hawks, etc. They live longest in the forest. Many species, especially long-living trees are effective in combating climate change. For example, Peepal tree, Neem tree, Banyan tree in India. Oak and Maple trees in the United States. The canopy layer is the most productive part of the forest. The layer receives the most amount of sunlight and creates food for the entire forest. It is also a spot of high biodiversity with butterflies, birds, and monkeys. Most fruit trees are part of this layer-custard apple and cashew tree. The short-lived plants act as compost for the forest. The shrubs and sub-trees form important sources of food. This could include banana, papaya, fig, and palm trees.

The impact of Miyawaki Forests

The Miyawaki forest technique has been a savior to the cities. The forest serves as an oasis in the concrete jungles. The trees help to lower air temperature, improve air quality, increase groundwater and invite local biodiversity. The native trees provide habitat and food to local varieties of butterflies, birds, and mammals like squirrels. In various cities of the world, the Miyawaki technique has led to a movement of ecological regeneration. Previously degraded lands like dump yards and landfills have been given a new life.

These forests store carbon. They regulate rainfall and naturally purify water. Apart from this, there are other impacts that these forests have on humans. The method can be a collaborative and inclusive method. It necessarily requires collaboration among the residents, the governing bodies, the scientists, and the environmentalists.Planting trees could evoke a sense of responsibility towards the environment. Thus this technique has the capability of bringing social mobilization.

Green Forest Wall, Japan

The Miyawaki technique has been tried successfully in all of Japan. It has been tried on wastelands, artificial islands, rock, and other difficult substrates. A grand project was started in Tohoku Japan to mitigate the effects of the tsunami. The Great Green Forest was designed by Dr. Miyawaki in response to the 2011 tsunami. The goal was to create a sea wall to protect coasts from future disasters. The non-hazardous tsunami debris was employed in an attempt to restore the damaged ecosystem of the coasts.

Miyawaki forests around the world

Dr. Miyawaki has instructed communities in Borneo, Chile, and Amazonia. His work is particularly focused on tropical countries. He has contributed to vegetation surveys in Thailand, Indonesia, and Malaysia. Since 2013, the method has been adopted by various organizations in India (Bangalore, Mumbai, and Chennai). In 2019, a sacred grove was planted in Punjab using the method. These experiments have shown that multi-layered forests can be built in 15–20 years in Japan and 40–50 years in Southeast Asia.

While the method has worked in cold-temperate and tropical climate zones, there have been few experiments in regions with high aridity. The Mediterranean climate is characterized by summer aridity and the risk of desertification. Climate change is inducing very similar weather conditions. Thus, trying the Miyawaki method in the Mediterranean context would be a true test of the effectiveness of the method. In 2000, the Miyawaki method was tested in Sardinia, Italy in an area where traditional reforestation methods had failed. This was the first attempt in a Mediterranean ecosystem. The original method was modified and the basic theoretical principles were kept.

Conclusion

The Miyawaki forest method is an incredible tool to push towards resilient cities. This method can provide quick fixes in this age of destruction. The technique can be used to heal degraded land and bring essential species back to the cities. An attempt should be made to learn about the native species. Starting a Miyawaki forest could be a huge step towards that!

Originally published at http://planetrescue101.design.blog on June 25, 2021.

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