BBorn in Calabria in 1965, Stefano Mancuso is a pioneer in the plant neuroscience movement that seeks to understand “how plants perceive their circumstances and respond in a complex manner to environmental influences.” Michael Pollan New Yorker described him as “a poet-philosopher of the movement determined to give plants the recognition they deserve.” Mancuso teaches at the University of Florence, his alma mater, where he directs the International Plant Neurobiology Laboratory. He has written five bestselling books on plants.

What underlies your love for plants?
I started getting interested in plants at university. One of my tasks while working on my doctoral dissertation was to understand how a root growing in the soil can bypass an obstacle. My idea was to film this movement, but I saw something different: the root changed direction long before it touched the obstacle. He was able to sense the obstacle and find a more comfortable direction. It was my first moment of insight when I began to imagine that plants are intelligent organisms.

You call your field plant neuroscience. This is a provocation?
At first this was not true at all, I began to think that almost all the statements about the brain that I heard were true for plants. A neuron is not a miracle cell, it is a normal cell capable of producing an electrical signal. In plants, almost every cell is capable of doing this. The main difference between animals and plants, in my opinion, is that animals concentrate certain functions inside their organs. As for plants, they spread everything throughout the body, including the intellect. So in the beginning it was not a provocation, but there was a strong resistance among my colleagues to the use of such terminology, and so after that it became a provocation.

What did you hope to achieve with your A new book, tree stories?
What I would like to popularize is, firstly, the many abilities of plants that we usually cannot feel and understand, because they are very different from us. Secondly, when talking about life on this planet, not talking about plants, which make up 87% of life, is nonsense.

You passionately advocate filling cities with trees. Why is it so important?
We produce 75% of our CO₂ in cities, and the best way to remove that CO₂ is to use trees. The closer a tree is to a source of carbon emissions, the better they absorb it. According to our research, we could plant about 200 billion trees in our urban areas. To do this, we really need to imagine a new type of city, completely covered with plants, without any border between nature and the city.

You have a fascinating chapter on a stump that has been supported by neighboring trees for decades. What can people learn from tree communities?
Plants cooperate so incredibly with each other because cooperation is the most efficient way to ensure the survival of species. Misunderstanding the power of community is one of [humanity’s] basic mistakes. At the beginning of the last century, there was a very smart evolutionary biologist, Peter Kropotkin, who said that when there are fewer resources and the environment changes, then cooperation is much more effective. [than competition]. This is an important teaching for us today because we are entering a period of resource depletion and the environment is changing due to global warming.

To what extent can plants communicate with each other? If you have a spectrum with rocks on one end and people on the other, where do the plants sit?
I would say very close to the person. Communication means that you can convey a message and there is something that can receive it, and in this sense, plants are great communicators. If you cannot move, if you are rooted, it is extremely important for you to communicate a lot. We experienced this during self-isolation when we were stuck at home and the internet traffic skyrocketed. Plants are required to communicate a lot, and they use different systems. The most important is the volatiles or chemicals that are emitted into the atmosphere and transferred to other plants. It is an extremely complex form of communication, a kind of vocabulary. Every single molecule means something, and they mix very different molecules together to send a specific message.

The idea that plants are sentient is debatable enough, but you’ve taken it one step further by arguing that plants are conscious to some degree…
Talking about consciousness is incredibly difficult, first of all, because we don’t really know what consciousness is, even in our case. But there is a way to talk about it as a real biological feature: consciousness is something that we all have, except when we are very fast asleep or under anesthesia. My approach to studying consciousness in plants was similar. I started by testing to see if they were sensitive to anesthetics and found that it was possible to anesthetize all plants using the same anesthetics that work on humans. It’s extremely exciting. We thought consciousness was connected to the brain, but I think both consciousness and intelligence are more embodied and connected to the whole body.

So you can put the plan to sleep?
We’re working to see if it’s okay to say so. This is an incredibly difficult task, but we think that before the end of this year we will be able to demonstrate it.

As we learn more about the sophistication and sensitivity of plants, should we think twice before eating them?
This is an interesting question. Many vegans have written to me asking about this. Firstly, I think it’s ethical to eat plants because we are animals, and as animals we can only survive by eating other living organisms – this is a law that we cannot break. Secondly, it is much more ethical to eat a plant than, for example, beef, because to produce a kilogram of beef, you need to kill a ton of plants, so it is much better to eat a kilogram of plants directly. The third point is that it is very difficult for us to imagine ourselves as plants, because for us to be eaten is an ancestral nightmare, while plants evolved to be eaten, this is part of the cycle. The fruit is an organ designed to be eaten by animals.

So fruit is probably the most ethical thing you can eat, even more than, say, cabbage?
Perhaps fruit is the most ethical, but after that you need to defecate on the ground because otherwise you break the cycle.