INTRODUCTION

Outside our bodies, there is another pulse that keeps us alive. It is the green of the living landscape. The trees of the forest offer oxygen and our lungs receive it. In and out, back and forth, beat, beat, beat, we are made and remade from the breath of trees, with sprinkles of stardust from the solar system and beyond.

We all feel this connection from birth. Our communion with trees is written plain as day on the face of any child let loose in the forest. But articulating the fullness of this relationship, the many ways our souls, spirits and lives depend on trees, is no mean feat. It requires scientific and spiritual knowledge, study and lived experience, and a willingness to listen—particularly to the trees. It is a life’s work. It has been mine.

That work, and by extension this book, began with the deaths of my parents when I was a young child. With no one from my father’s aristocratic English family willing to claim me, fate could have ended my life in an Irish Magdalene laundry. Instead, it gave me a great gift. Splitting my time between Cork, where I excelled in school and read everything I could in the book-lined house of my mother’s brother, my uncle Patrick, and the valley of Lisheens, where my great-aunt Nellie and the rest of an older generation of subsistence farmers taught me the ancient Druidic knowledge of the Celtic culture, I received an education that was wholly unique. I learned the Brehon laws of the Celts, the distillation of three thousand years of wisdom, and I was taught the uses of medicinal herbs that have since found their way into today’s cutting-edge medicines. At school, I turned out to have a photographic memory for equations and chemical formulae. I studied botany, physics and medical biochemistry. I earned a master’s and a PhD. I led research projects, but ultimately fled academia to found my own experimental farm.

In short, I have learned to speak the chemical and spiritual languages of nature. I am still learning.

When I left Ireland for North America and postgraduate work, the elders of Lisheens threw me a kind of going- away party. A local woman known for her ability to see the future was invited. She was asked to look into mine. She told me I would go to the “New World” and share the gift of my Druidic education, that I would teach people about the value of nature and their connection to it, and help humanity cast off its greedy, destructive ways. I have tried all my life to live up to that prophecy, and in that spirit I have shared my knowledge and brought my abilities to bear wherever I thought I could do good. I have contributed to the protection, establishment and preservation of forests on six continents. I have written many articles and books, have given countless interviews, and was the centrepoint of a documentary on forests, among many other projects. And, crucially, I have never stopped my scientific work, my on-the-ground observation and experimentation. This book is a continuation of that life’s project, another effort to share what I’ve learned and to encourage others to pick up the threads, to take on the work.

As I write this, I am approaching my eightieth birthday. I am not a person who thinks much about my age, but I suppose there is some cause for reflection and appraisal in that milestone. As I look around—my life, my farm, our world—I see so many fundamental questions about trees, forests and our living planet still waiting to be answered. How do trees defy physics and run water uphill? How does a petiole move a leaf to track the sun? How does a tree make judgments about the future? Could oak leaves hold the secret to free, renewable energy?

I also see so many fascinating examples of the forests’ vital role on the living planet: trees’ powers to battle cancers and depression in humans; the controlled dosages of medicine they deliver to forest bathers; the ways forests seed the oceans with metals necessary for the foundations of marine food chains; the ways they speak in chemistry and infrasound. And finally, I see, in climate change, the greatest challenge humanity has ever faced.

This book is a reminder of all trees do for us. It is a reminder of their central role in the healthy functioning of this planet and everything—everything—that lives upon it. It is a reminder of the destruction we have wrought on the forests through our greed and thoughtlessness, and the consequences of that destruction. And it is a reminder that the only way out of this mess we have made is to protect the forests and plant new ones.

Our Green Heart is not about the past. It is about the work still to be done. It is about the solutions still to be found in trees and plants. It is about a concrete plan to end the climate crisis.

This book is about hope. This book is about tomorrow.

Its pages hold a different vision, one of co-operation and compassion, one that offers a fresh green horizon for us all.