The willow tree is a shadow of what it once was. Struck by lightning, it has neither leaves nor branches — just a slim trunk that stretches upward and splinters into sharp blades.

To the casual observer, the willow looks much like the surrounding trees in the vast park that is Kensington Gardens. Yet it’s actually a bronze sculpture: It was cast from a 100-year-old willow tree (and lined with gold leaf) by the Italian artist Giuseppe Penone, and it is part of his new solo show, “Thoughts in the Roots,” at the Serpentine Galleries through Sept. 7.

Penone, 78, makes art with, and about, nature. Trees, wood, leaves, plants and rocks are his principal materials. Inside the Serpentine, he has lined the walls of the central gallery with laurel leaves that give off a delicate scent. Standing against one wall is a sculpture made of timber beams whose outer layers have been stripped away to reveal what lies at their core: the tiny branches of the young trees that they once were.

Penone was born into a farming community in the mountain village of Garessio, in northwestern Italy. He spent his first couple of decades far from the big city, surrounded by forests and rivers. Yet art was always a part of his life. He drew from an early age, encouraged by his mother — who had dabbled in art when she was younger — and grew up in a home that was filled with busts and figurines made by his sculptor grandfather.

He later studied at the Albertina Academy of Fine Arts in Turin. Yet his first steps as a practicing artist were taken among the trees in his childhood village. In 1968, when he was 21, he made a mold of his hand and affixed a metal cast of it to the trunk of a tree; over time, the tree grew around it. He documented that and a few other bucolic interventions when he did them. The photographic series led the influential Italian critic Germano Celant to include Penone in his book “Arte Povera” (“Poor Art”) — and to associate him with one of the major art movements of the 1960s and ’70s.

In a recent interview at the Serpentine, Penone spoke of his relationships with nature, art and money. The conversation, translated from Italian, has been edited and condensed.

Why did you make nature the basis of all of your artworks?

For reasons having to do with identity. I thought to myself: If I want to express something with figurative art, I need to do something that is mine — an imagery and a practice that are personal. I need to work with the elements which I know best, which I feel most strongly about. There is no point in doing what others are doing. My art was born of that very simple intuition.

That’s where I got the idea of working with trees. The tree is not a fixed or rigid form: It’s a form that is in motion. We see it as a solid form, but it’s fluid in time. I went back to the places of my childhood. I drew inspiration from the relationship with nature, and from the farmer’s life: the idea that you plant seeds and there’s a harvest, that you put something in the ground which reappears as a crop. There is a waiting period — it’s not an immediate process.

Did you feel at home in the Arte Povera movement?

You have to consider the situation of contemporary art in Italy at the time. There were collectors and artists, but there was no structure, no museums, no market, nothing. So the expression “Arte Povera” became a structure, an identity which artists accepted and found that they could work with. Setting aside the economic considerations, artists accepted to put on exhibitions under that label, because they could retain their own distinctive identity while making work that threw into question the conventions of art.

Was your career a consistent success, or were there ups and downs?

I never noticed the ups or the downs. I continued to do my work even at times when the market was in a downturn. My work is not based on exhibitions: It’s based on a relationship with the material. It’s like writing. As long as you have a pen and paper, you can work.

Yes, but you do have to survive.

I found a way to survive. Somehow the work would sell. Something would sell.

In the world today, there’s a major concern for the environment, and a return to nature. Your works are very much in tune with the times. What are your thoughts?

I am very pleased that there is a synchronicity between what I do and the times we are living in. But there’s a fundamental contradiction in seeing nature as something that’s extraneous to humankind. Human beings are part of nature. They are nature. They have to preserve nature for their own survival. So this is not about human beings loving nature: It’s about human beings loving themselves.

All of these debates around the environment are to do with the human ego, and they’re focused on the survival of humanity. It’s somewhat ridiculous to say that human beings need to be concerned about the survival of nature. Even if human beings are extinguished, nature will continue to exist. Another living being will come along and overtake humanity.

Isn’t there a contradiction in making work that is close to nature and to your rural roots, and being represented by Gagosian, the world’s biggest commercial art gallery?

The relationship with a gallery is two-sided. The gallery sells the work of the artist, but the artist also makes use of the gallery. There are benefits for both sides, especially when a gallery gives as much freedom to the artist as Gagosian does.

Before I started working with Gagosian, I had a lot of doubts, because I heard critical comments about the gallery. But in all of the exhibitions that I have put on, the gallery has never asked me to produce a marketable work. The main purpose has always been for me to make interesting work. Larry Gagosian’s vision is to put on shows that are museum quality, for which he requests museum loans. Obviously, he might also sell a work, and he might sell it well. But he plays a cultural role.

What is the role of art and the artist in the world today, with all of the advancements of technology?

What it has always been: to create emotion and surprise, stimulate the human imagination, and make individuals think and reflect when they’re faced with the unforeseen and the unknown. The point is to preserve the sense of wonderment that children have.

Art has to have a profound social function, not just an aesthetic function. It has to make people understand the reality that they are living through, and how that reality is transforming over time.