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Vol. XXX No. 23, April 1-15, 2021

Miyawaki forests to increase green cover in city

by Padmaja Jayaraman

A view of the mini-forest raised along the Canal Bank Road in Kotturpuram.

In November 2019, there was a 23,000 square feet area in Kotturpuram, with garbage dumped to a depth of four feet. Next year, the dumpsite transformed into a mini forest with 2,000 native plants, volunteers’ efforts and 15 lakhs funded by the Greater Chennai Corporation. The incessant debris was cleared and replaced with topsoil that was obtained from restoring lakes. Thus sprang the first Miyawaki forest in Madras.

The success of the first Miyawaki experiment in Kotturpuram sparked off the creation of other urban forests in the city. Presently, there are 30 Miyawaki forests with a total of 60,000 saplings in areas including Valasaravakkam, Sholinganallur and Mugalivakkam. NGOs called Trees Trust and Thuvakkam came on board for the completion of these Miyawaki projects.

In 2019, Care Earth Trust, an NGO that takes up environmental restoration activities in the city, conducted a study on the green cover of Madras for GCC. They found that the tree cover had to be increased in the city. The NGO recommended that at least 2 lakh trees hade to be planted every year (that is, one million trees in the next five years). The Union Ministry of Forests, Environment and Climate Change has also recommended 33 per cent green cover in Madras. Currently, the city has 19 per cent. To increase the number of trees and plants in the city, the Miyawaki method was suggested.

Miyawaki forests will improve the area’s micro-climate, but may not impact the climate of the entire city, says Dr. Balaji Srinivasagopalan, former Principal Chief Conservator of Forests. The tree roots will also hold the soil together and facilitate rainwater seepage. Additionally, urban forests are supposed to reduce the heat island effect. “Heat reflected by glass and concrete is common in a city like Madras, especially due to a lot of IT parks and other glass buildings. These heat waves constitute the heat island effect,” explains the former forest conservator.
While talking about the nature of Miyawaki forests, he says that they are just emulations of natural forests. “Natural forests take many hundreds of years to emerge. Just 30 centimeters of topsoil takes 200 years to develop. But Miyawaki forests can come into fruition within 3 to 4 years,” he adds.

The relatively fast growth rate of Miyawaki forests can be attributed to the practice of planting native species very close to each other. For instance, in the Kotturpuram Miyawaki forest, local species like peepal, jackfruit, neem, hibiscus, banana and papaya saplings were planted at a distance of one metre from each other. “When you plant trees close to each other, they tend to grow taller. If you space them in a wider area, then they will start branching out. That is, they will grow horizontally also,” explains Dr. Balaji. Consequently, the green density of Miyawaki forests is typically thirty times greater than usual and the growth ten times faster. Within a year of its inception, the Kotturpuram urban forest has yielded banana fruits, hibiscus flowers, papaya and drumstick pods, with 70 jackfruit trees, 40 tamarind trees and 50 neem trees competing for space, reported The Hindu in February 2021.

In half a year, locals will be permitted to enter the Kotturpuram Miyawaki forest for walking and other activities. GCC intends to create 1,000 such small forests in different parts of the city with the help of open or reserved areas in future.

The Miyawaki method of afforestation was founded by Japanese botanist Akira Miyawaki in 1970. He proposed planting multiple layers of native plants to grow a forest – a canopy layer, tree layer, sub-tree layer and shrub layer. The mini-forests of Chennai follow the same technique.

Apart from the rapid growth of flora, Miyawaki forests have other advantages which outweigh the relatively high expenditure and effort they consume during the first two years – they each grow into a self-sustaining ecosystem that supports various animals, birds and insects. Moreover, these forests are not burdened by weed growth – since the plants are planted close to each other there is no space for unwanted pests to sprout. This further strengthens the theory of the Miyawaki method: ‘Zero management is the best ­management.

Dr. Balaji shares how Miyawaki forests can be created: “A mini-forest can even be started in 10 to 20 meters width too. Accordingly, we have to choose native plants for 4 to 5 layers. It takes a lot of planning. You plant a dominant tree in the centre which needs sunlight, and plant a tree close by that can survive in the shade. Then shrubs, climbers and herbs. The soil has to be dug up and organic manure and good soil must be added.” The Kotturpuram urban forest used 80 tonnes of compost, 18 tonnes of coir pith, 12 tonnes of cow dung and two tonnes of straw for organic manure, reported The Hindu in February 2021.

Though the Miyawaki method is a quicker way of creating forests, it has its own limitations. “It’s not an alternative to normal plantations. It can only be developed where there are space constraints. Under normal circumstances regular plantations are the best,” said Alby John Varghese, Greater Chennai Corporation’s (GCC) Regional Deputy Commissioner (South) to The News Minute.

Further, not all environmental experts agree with the Miyawaki approach, particularly in congested urban locations. Shobha Menon, founder trustee of the NGO Nizhal is one of them. “Many people want to employ this method to create a forest in double-quick time. But that is not how nature works. We cannot undo the harm we have done [to the environment] immediately. We actually cannot create a forest; what is being done is planting trees and making an area wooded,” she points out. “It will turn into a forest only when all the multivarious biodiverse interlinkages happen in the area. Deciding sensitively what and when to plant, what combination of trees, shrubs, climbers etc. is a complex business.”

Shobha also feels that public awareness of the importance of nurturing and caring for green spaces is crucial and possibly more important than rapid growth techniques. “It is important to inculcate the concept of caring for their green spaces in a continuous manner in the minds of people,” she remarks. She speaks from experience – Nizhal aims at conserving green cover in Madras and has seen success with setting up a tree park in Kotturpuram in 2010, next to the area’s MRTS campus, just 1.4 kilometers away from the Miyawaki forest.

Nizhal’s advisor, Dr. T.D. Babu shares the shortcomings of the Miyawaki method. “In an area meant for 100 trees, if 1,000 trees are planted, they will reap lesser ecological benefits. The trees are incapable of growing to their full natural profile, spreading their branches. Miyawaki forests cannot effectively absorb carbon dioxide, because the surface area is lesser in Miyawaki forests when compared to traditional forests,” he explains. This is a key point – an increase in carbon dioxide leads to increased temperatures and it is through photosynthesis that plants help cool down the area in their vicinity. The reduced leafy surface area also means lesser transpiration – the process by which plants release excess water vapour – and therefore, a weaker impact on rainfall rate.

Interestingly, Dr. Babu feels that the Miyawaki approach has only led to greater use of concrete than nurturing more green cover. “The Miyawaki method is shrinking the green canopy of Madras, growing the concrete jungle instead. That was what happened in Shenoy Nagar’s Thiru vi Ka park of 8.8 acres. There was a large area of green canopy that has been converted into a metro station in 2017. The authorities claim that they have compensated by planting more trees than those in Thiru vi ka park, by planting at the four corners using the Miyawaki method. One can observe the impact [of the Miyawaki method] before and after – today, it is just concrete”, claims Dr. Babu. He feels that 100 or 200 trees could have been planted in the Kotturpuram Miyawaki forest instead of 2,000; that would have brought a greater cooling effect.

Dr. Balaji points out that Miyawaki forestry is just one of the methods to increase the urban tree cover in Madras. He suggests three other methods to increase the percentage of greenery in the city. “The first method is, we can find institutional lands such as offices, schools, factories or wherever there is enough space, and we can plant trees. The second method is, construction of more service roads in the city for planting trees on the sides with no hindrance. Most of the other roads have various wiring and piping networks underground. While doing repairs, the roads would be dug, and the roots of the nearby trees will be damaged. The service roads would provide an alternate location for trees to grow, without any underground obstructions. The third method is to mandate every house in Madras to grow 4 to 5 trees. Each house can grow useful trees like drumstick, banana or mango. At least they can have it in four corners of the house, even if most of the spaces are given to car parking. It will improve the green cover of the city on a micro level,” he says.

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