Mini-Forest Revolution, by Hannah Lewis – Book Review

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Robert Pavlis

Mini-forests are popping up all over the world and even my own town planted one in this past summer. I wanted to learn more about this new trend and the book, Mini-Forest Revolution: Using the Miyawaki Method to Rapidly Rewild the World, by Hannah Lewis, (Amazon affiliate link) seemed like a good place to start. It describes a movement to restore biodiversity by transforming empty spaces and degraded land into mini-forests. Here is a review of the book.

 

hand holding the book titled Mini-Forest Revolution
Mini-Forest Revolution by Hannah Lewis, source Topia

Review of “Mini-Forest Revolution”

The book is well written in a conversation style that is easy to read. It provides a good background to the Miyawaki method and then goes on to discuss the development of various mini-forests all over the world. It also has a how-to chapter that readers can use to implement their own forest.

The book is focused on providing an historical account of how this technique has spread from country to country and it provides good insight into the key players involved in the process. It also looks at the environmental impact that such a forest has on the land where it develops. The title is well suited since it focuses on how the technique evolved over time and its effect on the land rather than the technique itself.

What is missing is a critical review of the method. There is reference to the fact that forests provide benefits, but there is no attempt to quantify the value of the mini-forest technique in comparison to other reforestation techniques.

Plant Science for Gardeners by Robert Pavlis
More Information about forests: Do Forests Remove CO2?

The Miyawaki Method

The technique was developed in the early 1970s by Akira Miyawaki, a botanist and plant ecologist, who researched ways of converting undeveloped land into forests. By planting a variety of species in extremely close proximity, he found that trees grew tall at a rapid pace. His technique will grow fast forests.

The method is well outlined in Mini-Forest Revolution and uses these key steps:

  • Improve the soil.
  • Select diverse native plants (understory as well as trees).
  • Plant very close together (3 plants per square meter – 9 sq ft).
  • Mulch well.
  • Maintain the planting for a few years.
  • Watch the forest to develop.

The method is different from other forest restoration techniques in two main ways; a strong focus on amending and improving the soil so trees get a good start, and planting close together. The focus on a mixture of native species is also different than many other large scale reforestations.

How do you define native species? The book outlines development of mini-forests in Paris where they define native plants as those that were in the region prior to AD 1500.

wide stone pathway through a forest.
Fourteen-year-old Miyawaki mini-forest in Japan, Courtesy of Doryu Hioki. source: Mini-Forest Revolution (Amazon link)

The Revolution

The term “revolution” in the title is fitting but may be a bit strong. The method was slow to be adopted, but in recent years is being used at a much more rapid pace. Most people are still not aware of the technique and this is one good reason for reading the book. This method may become important in our efforts to fight climate change.

It all started in japan where Miyawaki developed the technique and started some exploratory forests. The idea was adopted by Shubhendu Sharma in India and he went on to popularize the method and modify it to be more easily adaptable. He founded a company called Afforestt that not only promoted the technique in India but also in Europe. Sharma said Miyawaki forests grow 10 times faster, 30 times denser, and are 100 times more biodiverse than a conventional plantation.

The author provides details of how the method was implemented in France and how she became involved in planting some forests herself. This personalized account provides a unique insight into the process and illustrates how non-professional people play a critical role. While describing one such planting, Hannah Lewis writes about one of the tree planters saying, “You know, I’m going to be able to come by here and show my kids that I did that. It feels good. It makes my heart feel good.”

The book goes on to describe more mini-forest plantings in The Netherlands, the UK and North America. Lewis reports that by year end The Netherlands will have 230 mini-forests. What struck me was that most of the global mini-forests have been implemented in the last 20 years and many in the last couple of years. Except in Japan and India, the mini-forests are all particularly young – for a forest.

Was there really a revolution of mini-forests? I think we are just now seeing the start of a potential revolution – if these forests really work.

Do Mini-Forests Work?

I first became aware of these while riding my bike in Guelph, my home town. Along the pathway I spotted a fenced off area that contained a huge number of newly planted trees and other plants. I stopped and read the sign that explained this was a test plot of a “mini-forest“. To be honest it seemed like a crazy way to plant. Far too many trees in a small space. A bit or research led me to the book, Mini-Forest Revolution. I was interested in learning more about how well these forests work.

The book does a good job describing the benefits of a forests, discussing things like biodiversity, improved water retention, cleaning ground water and cooling the land. However, these benefits are true for any forest planting. The book contains no real analysis of how well mini-forests work in comparison to traditional forests.

One problem seems to be a lack of research evaluating mini-forests. Most are still quite young and need to develop more before we know if they really work. Like many environmental issues, people are quick to jump on the bandwagon without knowing where the wagon is going. That may be the case here as well.

There is no doubt that mini-forests do develop into forests. I am also quite sure that the trees grow tall quickly – they have to if they want to get any light. What is not clear is whether this technique is any better than other planting techniques. We also have no information about the quality of these forests in the long term, compared to other methods. This will be the focus of a future post.

More Articles About Trees:

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22 Myths About Christmas Trees

Growing Under Walnut Trees

Planting Trees the Right Way

Pruning Trees and Shrubs – Will Late Summer Pruning Harm Them?

Should Trees be Wrapped in Winter?

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Robert Pavlis

I have been gardening my whole life and have a science background. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

6 thoughts on “Mini-Forest Revolution, by Hannah Lewis – Book Review”

  1. Don’t be despondent if you can’t grow a mini-forest, just plant ONE tree in your backyard/garden, it will give you pleasure, & is good for the planet

    Reply
  2. Hmmm… the concept is very interesting to me. But not all plots of ground are suitable to be ‘forests’ as in woody plants (trees/shrubs). What if you live in high desert, desert, prairie, or tundra? The author’s definition of ‘native’… ‘in the region prior to AD 1500’… is my main objection. Prior to AD 1500, really? I thought there we have evidence of climate change where many areas are a good bit warmer than they were prior to AD 1500. Some areas are colder. I know where I currently live, some of the ‘native’ trees are dying due to heat. And is there a definitive resource to tell us what was native in our area prior to AD 1500?

    I love trees. I’m not trying to discourage planting trees. I am just wary of this book’s apparent definition of nativeness. Guess I’ll have to read the book to know what is being talked about for sure.

    As always, great post!

    Reply
  3. Interesting I have been doing mini mini forests for close to 30 years. These are bonsai forest style mostly monoculture (the odd mixed forest) and upwards to 30+ trees on a stone slab. They do tend to be large and two to three people are needed to move around.
    Myself and some of my peers have managed to plant mini forests in our gardens with Mt Hemlock, Shore Pine, Sub alpine fir as well containing understory plants. Being on the west coast the understory plants (referred to as accent plants) are; Cornus, Kalmia, various ferns, mosses, huckleberry etc.

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  4. This is an interesting approach to restoring native plants and it is desperately needed to protect and restore biodiversity of all kinds. Left undisturbed, these areas will most likely naturally thin out with age due to competition for sunlight and nutrients. In nature, depending on the location, soil conditions and the types of plants pre-existing, following a natural disaster, it is not uncommon to see a dense variety of plants emerge. I’ve seen this on some of the large fire scars in the Sierra Nevada where I live. The density of the emerging vegetation quickly becomes another highly flammable area for decades until the area thins out. Unfortunately, without native land management using fire, that generally doesn’t happen without severe droughts, winds, heavy snow, etc. All the research going on with forest management in the west seems to indicate a need to thin out a lot of the vegetation to get that happy medium that results in the healthiest trees at a density that is more resistant to damaging wildfires while supporting a good diversity of organisms.

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  5. This is similar to our (not implemented anywhere) 1998 plan for “instant oldgrowth:” dig microtopographic relief, import coarse woody debris, cover the site with manure, minimal spacing between planting a diversity of shade-tolerant and shade-intolerant tree species and understorey shrubs and herbs, with vernal pools to provide Amphibians. Instant shade was going to be provided by Jerusalem Artichokes. We’re working on a version of this now in an Aspen/Sumac grove on an old garden on our land, though without the massive infusion of nutrients.

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