The sun shines. But only a few spots of light find their way down to the ground in the small forest of Alphen aan den Rijn in the Netherlands. More than that do not make it through the dense foliage.
The forest is one of three so-called “mini-bos” in the city, which has just over 110,000 inhabitants. Since the first mini-forest was planted in the country in 2015, there are now small forests in 300 locations.
— 10,000 years ago, Holland was a forest, and if we didn’t do anything, it would grow back in a hundred years, says Daan Bleichrodt, who works for the nature organization IVN and is the author of a book about mini-forests.
The forests connect people in the cities closer to nature, involve school and preschool children in planting and care, and also increase biodiversity and contribute to climate-safer cities, according to IVN.
— Since 2018, when the project began to take off in earnest, we have experienced drought, heat waves and floods. People have started to worry more about the consequences of climate change, and want to act. And the micro-forests are very tangible – it’s a small project, it can be started within a year, says Bleichrodt.
The plants in Helsingborg are close, close. The idea is that the competition should stimulate the plants to grow faster and stronger.Japanese method
Interest in planting small forests has exploded in recent years around the world. In cities on every inhabited continent, patches, sometimes as small as ten by ten meters, have been planted.
The Japanese botanist Akira Miyawaki has given his name to a method that involves enriching the soil and introducing a variety of native plants, which grow up to ten times faster than conventional forestry.
— By planting plants close together, loosening the soil and making it more nutritious, you can get the same kind of forest that would occur naturally in a hundred years in ten years. But it’s not like the trees grow ten times faster, says Daan Bleichrodt.
In a short time, the forests have become home to a multitude of species – everything from birds and insects to foxes and hedgehogs.
— The first forest we planted is huge today, twelve to fifteen meters high, and teeming with life. We have ecologists from Wageningen University who have followed the diversity for five years and they found more than 300 species that are or have been in the forest.
Elias Halling, landscape architect at the city of Helsingborg. Several in Helsingborg
Elias Halling is a landscape architect in the city of Helsingborg. Since 2020, he has planted 15 micro-forests, not entirely unlike the Miyawaki method, in the city.
— We saw that there were many open grass areas that were not being used. And we had many trees in mainly exploitation areas that did not develop as we wanted, they stood and stomped and got nowhere in their growth power.
Halling and his colleagues tried buying many small seedlings and planting them close together.
— They must compete with each other to grow faster and become stronger. That’s how a forest works. Instead of planting a tree that is having a hard time, you plant a group of friends, and then they help each other.
Later, you may have to thin and select the trees you wanted to keep.
— It’s not always about finding a straight tribe, but rather about individuals full of character.
A rest area for dogs, a relatively newly built residential area, a green lane and a lawn outside a preschool have received plantings. The smallest are only 60 square meters, while the largest is 800. The largest trees stretch four to five meters into the sky today.
Small signs explain what’s going on, which can be good, Elias Halling thinks, as the micro-forests don’t look like traditional plantations. It has not only been positive views, although most are.
— There are many who think it’s nice, that greenery comes up immediately.
Elias Halling has followed the development of Helsingborg’s micro-forests. In just two years, they have shot up a couple of meters in the air. Several wins
Johanna Deak Sjöman at the Swedish University of Agriculture (SLU) sees an increased interest in small forests in urban environments, although not necessarily according to the Miyawaki method.
— As we live in a time when we don’t have much space left for the green in our cities, it’s important to see how to get the best possible out of as small an area as possible.
In addition to the city dwellers getting close to nature, there are other benefits. The trees cool the ground and buildings on hot days, their water absorption capacity naturally reduces the risk of floods and the forests act as small carbon sinks that bind carbon dioxide.
Deak Sjöman also emphasizes the aesthetic values. A dull courtyard, an old parking lot or a grassy area can be transformed into an exciting forest. And not everyone has to be cast in the same mold.
— We can work in many different ways with mini-forests, you can create interesting layers, both on the ground, in the middle and on the upper canopy level. You don’t have to have the same model, you can be quite free in your design so that it corresponds to the different needs of people in the city, she says.
Microforests are small, cheap and fast-growing small forests that can relatively quickly produce positive effects for the environment and people.