The next time you pass by a tennis court, imagine if that space was a fully mature forest
Throughout the world, hundreds of urban micro forests have been planted, with most only being the size of a tennis court.
A Miyawaki forest being planted on the outskirts of Paris, France. Source: Boomforest.
Positive Impacts of Micro Forest
These micro forests are planted using a Japanese technique called the Miyawaki method, in which the soil is prepared with nutrients, and a mix of native tree species are planted closely together. The Miyawaki method allows for a rich, dense forest to develop within just a few years, transforming trees from a small ecosystem into a mature forest.
“By planting trees in a very loose nutritious soil and by planting them really close together, they can form this small ecosystem, and this really gives them the opportunity to grow old,” explained Daan Bleichrodt of Tiny Forests, IVN. He continued, “trees that grow old sequester a lot of carbon; they attract a lot of biodiversity.”
Young trees can absorb CO2 at a rate of 13 lbs per tree per year, which is equivalent to 14.6 miles driven in a passenger car. Trees, however, reach their most productive stage of carbon storage at ten years, at which point they are estimated to absorb 48 lbs of CO2 per year. That value is equivalent to 54 miles driven in a passenger car per year, or 2,777 smartphones charged. Although these values are small, if these micro forests are planted in communities throughout the world, the effects on climate change mitigation will not be trivial.
Resilient Bubbles of Nature
These micro forests act as "resilient bubbles of nature," acting as both a carbon sink and a hub of biodiversity, commented Clara Manuel, Urban Forestry Engineer. Many of these micro forests are planted in the middle of urban centers, which often experience higher levels of air pollution and CO2 emissions than rural or suburban areas. By implementing micro forests into urban centers, these forests serve to clean the air by filtering pollutants while absorbing Carbon emissions, which can mitigate the effects of climate change. Additionally, because urban centers have a tendency to insulate heat, planting micro forests in urban areas serves to counteract the 'heat island effect' by providing shade to the streets, simultaneously offering opportunities to reduce energy use for cooling buildings.
Urban centers are often noted for their lack of biodiversity, as the harsh urban environment makes it difficult for many species to flourish due to limited habitat and food availability. By planting micro forests in urban areas, these forests serve to provide a habitat for a multitude of species, amplifying biodiversity within the region and allowing for the proliferation of natural life amidst urban development. One study conducted by Wageningen University, NL, on micro forests discovered that one forest attracted 600 species of plants and animals.
A Miyawaki forest's progression from initial planting ( left image) to 15-months of growth in Kerala, India (right). Photograph: The Better India
These forests, however, are not without their challenges. The increased biodiversity that urban micro forests attract may bring unwanted animals such as foxes, which can pose a host of problems for urban centers and their residents. Moreover, because these forests are living ecosystems, the vegetation produces leaves and fruits, which may be wasted in urban environments, as they cannot pollinate the surrounding areas outside micro forests.
Mitigating the Effects of Climate Change Means More Micro Forests
Although one micro forest may have minimal effects on the global climate system, the proliferation of micro forests in urban centers worldwide can substantially reduce carbon emissions in the atmosphere while reducing air pollution and promoting biodiversity. For these forests to attain their maximum potential, they must be implemented in cities throughout the world. Bleichrodt exclaimed, “I feel that if we plant a lot of these forests, we can mitigate the effects of climate change, but we cannot stop it because we need to stop emitting carbon altogether.” He qualified, however, that if there are enough forests planted, they may buy more time to address climate change.
Volunteers with ReforestAction planting native seedlings Source: ReforestAction
An Outdoor Classroom
In addition to climatic and biodiversity effects, these micro forests provide an opportunity to educate urban residents about nature and give them access to natural ecosystems that may otherwise be inaccessible. Miyawaki forests offer communities the opportunity to gather in nature amidst urban environments and engage residents to work together, fostering community and neighborhood.
Bleichrodt commented, "In my wildest dreams, the forests would thrive, kids would come here every day for outdoor classes, and the local community would be very involved in the project." However, he admitted, “That often, in practice, only one or two of these goals are accomplished.” He added, "If forests are very popular and a lot of kids pay there, then biodiversity tends to do less well” because natural ecosystems thrive best when they are least interrupted.
Although climate mitigation would require hectares and hectares of micro forests, they can serve as a learning opportunity for children to learn to restore forests. With this knowledge, these children may grow up to plant more extensive forests, which would have a more significant effect on carbon sequestration.
If urban and suburban communities were to develop Miyawaki forests within their own neighborhoods — selecting vacant areas at least the size of a tennis court — these small vegetative areas could help to reduce global climate emissions while providing a rich, natural ecosystem in communities throughout the world. Furthermore, many of the micro forests currently in place have been planted and developed by community members who saw the potential benefits and wanted to institute change within their communities. To learn more about how to develop Miyawaki Forests, check out the resources listed below and speak with your neighbors about the possibility of creating a micro forest within your own community.
Resources:
The Miyawaki’s Forest Restoration Method - Boomforest
Role of Miyawaki Forests in Mitigating Urban Heat Island Effects - Mongabay-India
How to Grow Your Own Tiny Forest - TedEd
Tennis-court sized scrap of Bristol to become 'tiny forest' - The Guardian
This article is inspired by the film People Fixing the World: Forests the Size of Tennis Courts by Richard Kenny and Anna Holligan, appearing on BBC News.
Written by Mckenna Foy (Boston College’21), Sustainability Intern, Boyer Sudduth Environmental Consultants
