Interview of Olivier de Montety, co-founder of Treeseve, that brings the urban forests to the next level

Olivier de Montety co founder of Treeseve that plants Miyawaki urban forests

Olivier de Montety planted his first Miyawaki forest in 2019, in France. He is the co-founder with Sophie Grenier of the company “Treeseve”.

Their goal is to plant 1 billion trees with the municipalities and companies of France.


I dicussed with him for an interview. In the first part, he shares his experience on planting climate forests and in the second part he explains their vision on how to scale up the urban forestry.

– Jean-Baptiste from Restore Forest

Thank you Olivier for accepting this interview. We’ll start with the very first question.

When you are at a party, how do you say in a few words who you are and what you do?


– Olivier from Treeseve

We are building climate forests in and around cities.

Why? Because it is now necessary to go beyond planting, by ensuring a sustainable impact. Why climate forests? To clearly distinguish these forest areas whose exclusive vocation is to fight against global warming and to contribute to the adaptation to climate change, compared to timber production forests. These forests are different. We plant in urban and peri-urban areas, on unused land, which can be either just wasteland or old industrial sites for example.

Hands of a worker planting a Miyawaki mini forest

– Jean-Baptiste

How did you discover tree planting and what method have you applied over the years?

– Olivier

The starting point is an article by Bastin and Crowther in the journal Science, which I discovered during the heat wave of July 2019. Bastin and Crowther presented a new point of view in this very detailed article, which is called “The global tree restoration potential”. They estimate that there is 1 billion hectares of unused land worldwide on which we could plant forests. If we planted forests on this billion hectares, we could recapture 200 of the 300 gigatonnes of CO2 that there is in excess in the atmosphere. I liked this idea because it was the first time I read something that presented an ecological solution to the problem of CO2 overflow, with solid quantitative elements. This discovery set me in motion. From there, I did research to find out what were the best techniques for reforestation on these unused lands mentioned by Bastin and Crowther. This is where I discovered the Miyawaki method and its planting technique, which he had begun to implement since the 1970s.


At home, in the Loiret-Cher, I started by planting 1,000 m², 3,000 tree seedlings in November 2019. To test and check if such a size and number of trees were a feasible project. I was afraid it would be completely gigantic and infeasible. In fact, I realized that with two people I had recruited locally, a gardener and his assistant, in 3 days, we planted these 3,000 trees and shrubs. It was totally doable. It was economically and physically feasible to plant 3,000 young small trees, seedlings about forty centimeters high, 3 tree per m² and this on 1,000 m².


From there, we started discussing this approach with Sophie Grenier, with whom I worked on the financial markets. Sophie knew the aspects of investors and companies and their demand in terms of SRI (Socially Responsible Investment) commitments for investment funds and ESG (Environmental, Social and Governance) and CSR (Corporate Social Responsibility) for companies. A sector that I did not necessarily know. By talking together, both on ecological and botanical aspects and aspects related to business issues, we decided to create “Trees Everywhere”, which became “Treeseve”.


Treeseve was officially born in April 2020. During the lock-down, we created the company through videoconferences… We worked in ninja mode, from a distance, for three months to do a first small fundraise, with friends and our professional network. Then, we launched the 2020-2021 season with a second planting space of 800 m² on my land in the Loiret-Cher, based on lessons learnt from the first plot planted in November 2019. From winter 2021, we planted in Mulhouse and Burnhaupt, a small village a few kilometers from Mulhouse. We planted 36,000 trees on two lots, with real corporate clients. This moment was the real start of the company.

A plantation site of Miyawaki mini forest with young trees  and wood chips mulch

– Jean-Baptiste

Treeseve has already contributed well to urban planting in France (Treeseve website).

How many mini forests and trees did you plant in total? And how was the development?

– Olivier

For us, we are not talking about mini forests. Our plantations are on average rather between 3,500 and 5,000 m², with some higher cases approaching one hectare. Compared to the movement of mini forests which is more about mini forests from 100 up to 300 m², Treeseve is on a model of several thousand square meters, with projects beyond one hectare. We therefore do not use the term mini forest, we say forest island, grove or forest, beyond 5,000 m².


To date, in February 2023, Treeseve has already planted 20 forest islands. We just passed 200,000 tree and shrub seedlings, accumulated over these three seasons. Mainly in the northern third of France. Our largest regions are the Hauts-de-France, the Grand-Est, and a little in Normandy and the Center-Loire Valley and one plantation in Ile-de-France this winter.

Display board on a plantation site of a Miyawaki forest in Mulhouse planted by Treeseve

– Jean-Baptiste

How do your customers contact you? Do you do prospecting? Or do you now have enough visibility and they come directly to you?

– Olivier

It’s a bit of both. We have a lot of local prospecting work. From the moment we have found land near a municipality that has a renaturation project through reforestation, we will build a project. We carry out soil analysis and botanical analysis to choose the list of species we are going to use. We build a project a bit like a real estate developer and we sell this plantation project to first local, regional companies then national, as part of their CSR policy. Companies are committed, with their employees in general, on a plantation project that they will integrate into their CSR policy and their extra-financial performance report. It is a commercial work which is indeed very important with a dedicated commercial team.


Once the marketing of the project is well underway, we launch the realization of the project. Tillage begins with decompaction, then a more superficial treatment of the upper horizon of the soil, with the addition of amendments such as compost or biochar.


Then comes the planting itself. The planting is carried out with integration structures, EHSW (Establishment and Help Service through Work). Part of the planting is carried out with participatory days: with the employees of the companies which financed and often with the schoolchildren, the inhabitants of the commune or the community on which we plant.


These plantations are carried out during the winter season, between the beginning of December and the end of March.

A sky view made with a drone of a plantation of a Miyawaki forest done by Treeseve

– Jean-Baptiste

You really have the winning trio between citizens, the local community and businesses. So generally, it is the cities that provide the land and the companies that finance the project, right?

– Olivier

It’s our most common model, but it’s not the only model.

We also have several plantation projects on private land, which belong to companies that call on us to repair damaged land. In particular, we made an operation in Alsace, on the site of an old clay quarry where it was a question of repairing and restoring the surroundings of this old clay quarry. The quarry itself had become a lake and the surroundings were very damaged over the decades of use of this quarry. There was an area where there were deposits of everything that was removed from the ground, which was not usable in the brickyard and this area was quite sterile. We revitalized this barren area and replanted a forest.

We also have environmental compensation operations. When a company, a community or a creator of infrastructure damages or destroys a natural environment, it has an obligation of environmental compensation. In this case, we can intervene as an environmental compensation operator to create a nearby plantation that is likely to meet the equivalence criteria required by law. Treeseve has already carried out a project of this kind at least once, on a large construction site in the north of France. This is a sector in significant development.

But today, nine out of ten plantations are carried out on land belonging to local authorities.

– Jean-Baptiste

Usually, finding the land and the money for the project is the biggest challenge. What is your best way to be able to carry out these projects?

– Olivier

First, land must be found in urban areas and a community of businesses must be built which will contribute to financing, around this project and generally locally. This implies working more with agglomerations and urban municipalities, with a significant economic ecosystem, rather than with small rural municipalities. For example in Metz or Dunkirk, Treeseve has a local network which is now quite strong, with both a good relationship with the local community, the public actor, and a close collaboration with the local economic ecosystem.

A tractor making tillage to prepare the soil so it is not compact for plantation of a Miyawaki forest done by Treeseve

– Jean-Baptiste

You said that you are inspired by Miyawaki’s method and that you try to document your projects in a scientific way.

What do you think is the most important step in the Miyawaki approach?

– Olivier

So we can actually speak of an approach, more than a method, because Akira Miyawaki did not actually write a complete method himself, with a peer-reviewed scientific approach. There are a lot of partial documents floating around. What is most important for us today is the analysis of the soil and the analysis of the natural potential vegetation. Those are the first two things we do. So why soil analysis first? Because we work on urban lands which have often been roughed up, which may have been industrial land. I mentioned Metz earlier. In Metz, we plant in the middle of the town, on a land that was a barracks for 150 years, where there were traces of metal and hydrocarbon pollution, under a concrete and tar slab that had been there for several decades and that the municipality removed 18 months ago. We are working there on very poor soil, in which there was very little life and must first be regenerated.


The first point is essential: analyze the soil, understand if there are pollutants, validate if there are nutrients and see what must be done in terms of mechanical work and biological work to plant a forest in good ecological conditions and ensure a high survival rate.


For the second point, we are completely in line with the Miyawaki instruction, which is to plant locally with local species. On the one hand, we have work based on CNRS natural potential vegetation maps, which gives us the dominant local species everywhere in France, by zones. On the other hand, we carry out work based on the physico-chemical qualities of the specific soil on which we are going to plant, in relation to the vegetation of the area. We therefore select the vegetation based both on these maps, on our local surveys and on what we can co-construct with botanists, ecologists or local naturalists, which will help us to give us references on the local species.

A ladybug on a leaf showing the boost of biodiversity in a Miyawaki forest done by Treeseve

– Jean-Baptiste

On the project management side, what do you think is the best return of experience to involve the local community and get them on board?

– Olivier

When working with a community, it is important to make sure that the project is understood and supported by all types of elected officials and departments of the municipality. It is also important that our projects fit into climate plan commitments, the creation of biodiversity or a better life for the inhabitants.

Our projects therefore do not only concern the green space service. It also concerns the services of citizen animation, sustainable development, urban planning and economic development. We really need to meet and motivate all the players in the local community to understand their issues and how they can get involved in their specific field of activity around our projects. This is what we strive to do with our local authorities department.

A quizz from Climate Fresque is performed with volunteers during a plantation event of a Miyawaki forest done by Treeseve

– Jean-Baptiste

What part do you appreciate the most in these projects to create forest islands?

– Olivier

Obviously the nicest part, from a human point of view, is the participatory days. It’s an intense moment, a pivot moment. Last week, we had the two major projects for this year, near Dunkirk and in Metz. In both cases, elected officials come to see, understand and validate the project. School children also participate. Having children who come to plant, see and learn is always very motivating for our field teams and our animation teams. We also have adults who are the employees of the companies that finance or the inhabitants of the neighborhood who are going to pass. We generally try to do a quiz of the “Climate Fresque” so that the participants acquire a global understanding of the climate issues and stakes. After, they take a shovel and a seedling and they plant.


Working with EHSWs, people with disabilities, is extremely rewarding and satisfying on a human level. EHSW workers are fully aware that they are participating in a societal project, for citizens, at a large scale. There is a strong botanical technique, a new approach. They are very happy to learn why we make these dense forests, why we make such a wide choice of species and how we build it.


All the participants in the planting, whether they are EHSW workers, company employees, local elected officials, residents or schoolchildren, each with their own background, knowledge or questions in ecological or botanical matters, will discover on the land, concretely how to plant a climate-forest, what it will be used for and how it will develop.

The target to plant 1 billion trees with municipalities and companies in France set by Treeseve with Miyawaki forests

– Jean-Baptiste

What is your secret mission, your real objective behind planting these climate forests?

– Olivier

The goal we set with Sophie Grenier is to plant 1 billion trees in France with the municipalities. 1 billion trees is a round number, which enters into the global objective of 1,000 billion trees. This target has been set at the end of the Davos forum in 2020, it was a bounce on the famous article by Bastin and Crowther that I mentioned earlier.

1 billion trees, it’s actually the idea that there is a simple multiplication. There are 35,000 municipalities in France. If each municipality makes 1 hectare available to Treeseve and on each hectare we plant 30,000 tree seedlings (following the density level recommended by Akira Miyawaki), the multiplier effect is there: 35,000 times 30,000, that’s a little over a billion trees! This is our grand vision over fifteen years. This is what we want to achieve. So the objective is not secret, it is completely official: we want to plant 1 billion trees with the municipalities and companies of France!

Volunteers planting trees in a Miyawaki forest with Treeseve

– Jean-Baptiste

If in a year, I come back with a bottle of champagne, what could we celebrate? What is your next big challenge or goal for this coming year?

– Olivier

I think the challenge we have, like a lot of startups, is scaling up. Today in the Miyawaki ecosystem, we are already a very big player, the biggest player in France and in Europe. We are however not at all satisfied to be the biggest actor, because we are still very, very far from our objectives. So our objective within a year is to have doubled in size or tripled in size. It is this acceleration that allows us to be on the scale of the challenges.

We must be clear: planting Miyawaki forests, Tiny Forest in the Netherlands, mini forests in France, is always a good idea.

But we must be clear that, even if it goes in the right direction, it is not enough, we must be on the scale of the issue.

We must remember that what is at stake is a global climate issue. To achieve this global climate challenge, there is a global initiative called 1,000 billion trees. Treeseve is part of this 1,000 billion trees initiative, with our stake “1 billion trees”. To plant 1 billion trees, you have to build a large company, which will be able to plant millions or tens of millions, maybe a hundred million trees each year.

Which seems totally colossal. But which seems totally necessary to us.

Our big challenges are almost always related to know how we are going to grow fast enough to build climate forests around cities, towns, urban communities in France to create cool islands, create areas of biodiversity and better water absorption and retention, that will enable cities to adapt to climate change.

That is really the issue, the essential issue. This involves planting hundreds of millions of trees around all cities in France. So yes, we need mini forests, but we also need to plant tens of thousands of hectares of “large mini forests”. This is our challenge at Treeseve.

A sky view made with a drone of a Miyawaki forest planted by Treeseve

– Jean-Baptiste

For you, what have been three resources or books that help you in your nature restoration journey?

– Olivier

The first resource is the article that I mentioned earlier by Jean-François Bastin and Tom Crowther in Science “The global tree restoration potential”. The second resource was the discovery of the writings and lectures by Akira Miyawaki himself. And then the third resource is probably “La Flore Forestière Française” which is our bible and our bedside book. This book lists all the plant species and in particular the trees of French origin that we can plant in France, according to the climatic zones.

And on a more anecdotal or literary basis, there is also obviously “The Man Who Planted Trees” by Jean Giono. It’s a tale, but the aesthetic and moral value is also important in our approach.

– Jean-Baptiste

Who is the next person you would recommend to meet to inspire me on mini forests, but also the creation of forest islands or even more broadly nature conservation?

– Olivier

There is a forester in the South-East of France who I like. His name is Nicolas Luigi. Nicolas Luigi is a forest engineer. He works as a consultant for forest owners. He has a logging approach, with the Pro Silva association, which promotes much more diversity than is often practiced in France. He intervenes within the framework of what is called “irregular forestry with continuous cover“. It is a forestry in which you have small, medium, large trees, of several species. They never do a clean cut. They always take samples from mature trees, without ever creating holes. I think it’s a rich ecological approach, close to nature and Nicolas Luigi could speak hours about the benefits of this method.

– Jean-Baptiste

Finally, last question, if you had a huge billboard with a message for everyone to see, what would be that message?

– Olivier

Plant forests around your cities.

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