Seeing the woods (complex ecosystems) for the wood (timber)

I’m sitting on a log, watching the crispy leaves from a nearby forest dancing in the breeze; winter’s chilly promise is just around the corner. The rocks are hugged by a fluffy cloak of moss, their edges decorated by algae, like glistening jade necklaces. The log’s bark is covered in sunburst lichens and a stand of curly bracken embellishes the margins in the distance. There are no mature trees, but tree saplings are dotted across the landscape. They were planted here by humans, and now they compete and maybe even cooperate as their young branches and leaves with tiny chlorophyll parcels reach for the sky. Some saplings will hopefully survive and grow into a flourishing community. Many dangers lie ahead for them, but in the right conditions nature is remarkably resilient. This is the start of a forest restoration project – a local story of hope. And what better symbol of hope than the seed of a tree, fragile yet brimful of potential?

At a global scale, we teeter on the precipice of unrivalled biodiversity loss and climate chaos, so restoring forests (and other) ecosystems is vital. But the truth is that forest restoration often fails. It fails if we don’t consider the livelihoods of the people who live on and care for the land. It fails if we neglect to apply ecological knowledge or promote Indigenous leadership. And it fails because we often view trees as commodities or wooden street ornaments instead of complex systems. Underscoring all these issues is our growing disconnection from each other and the land beneath our feet, particularly in ‘high-income’ societies. It’s safe to assert that we cannot effectively conserve and restore nature if our worldview is predicated on control and convenience rather than reciprocity and belonging.

What exactly is a tree?

…and why is it important to restore trees in our landscapes? A tree is myriad things, transcending the boundaries of objectivity. A tree is a subject and a living community. A paper mill owner may see a tree as a resource: pulp-to-be. Living trees can be ancient. They’ve lived through medieval history, quietly witnessing our tragic and halcyon days. Some trees burst from their seeds and anchored their roots several millennia ago. Indeed, some living trees are nine times older than the first paper mill established in Nuremberg, Germany, in 1390. These trees continue to inhale our exhalations today as we inhale theirs. Carl Sagan famously said that it’s a “marvellous cooperative arrangement ... a planet-wide mutual mouth-to-stoma resuscitation”!

Where does the word ‘tree’ come from? The answer lies in thousands of years of history spanning the entire European continent. We know the word ‘tree’ was uttered in England 500 years ago by the great playwright William Shakespeare. Yet in tenth-century England the word typically appeared as treow, a derivative of the Germanic treuwaz. This stemmed from another word, dreuom, around 3,000 years ago. But we can travel back further still, to 4,000 years ago and to the land around the Caspian Sea, where the etymological trail ends. Peoples of the Kurgan culture spoke Proto Indo-European – the oldest predecessor of Modern English – and used dóru to describe a tree. This word carried meanings such as ‘steadfast’, ‘hard’ and ‘strong’. We somehow got from dóru to ‘tree’, but it’s easy to understand the reasons behind the meaning – trees certainly conjure up images of strength, hardiness and resilience in my mind, along with beauty, serenity and wisdom.

Senses and memory

“Breaching out of their rooted darkness,
breakthroughs
are seeds of nonconformity
determined to sprout into the light of free
thinking.” — Monica Gagliano

So many brains, I think to myself. I’m walking around UCL’s Grant Museum of Zoology and there’s an entire section devoted to brains in jars. Each is preserved in alcohol and suspended by a thread. There’s a pigeon and a turtle brain, but most are from mammals, collected from Africa, Asia, South America, Australia and Europe. Being surrounded by so many brains got me thinking about nervous systems, senses and cognition in our leafy friends. Do these phenomena exist?

Trees don’t possess brains or central nervous systems, which we typically associate with the processes of sensing and remembering in animals. However, research implies that they can interact with their environment in complex ways that may be viewed as sensing. They are also able to respond to environmental changes in ways that might be seen as analogous to memory. ‘Sensing’ in biology generally refers to the ability of an organism to detect and respond to certain stimuli in their environment. These stimuli can be external, such as light, sound or temperature changes, or internal, such as biochemical changes. I would therefore argue that trees certainly are capable of sensing.

Trees can detect and respond to a range of environmental cues. For instance, they can sense light, which directs their growth, detect gravity, which helps them orient their roots downward, and respond to sound and touch (e.g., by growing thicker or changing direction when faced with physical obstacles). Evidence suggests they can also sense chemical signals, such as those released by pests, and respond accordingly by producing defensive chemicals. As for memory, it’s important to clarify what this means. In human terms, memory usually implies a conscious recollection of past events. Evidence suggests that trees probably don’t have this capability but can alter their growth patterns and physiological responses based on past experiences. For example, trees can acclimatise to changes in climate. If a tree experiences a few years of drought, it might ‘prepare’ itself for future droughts by altering its water use strategies, growth rate or other aspects of its physiology. In a sense, the tree is using information from its past to inform its future responses – a process that might be considered a form of memory. We know that trees retain a record of history. For instance, it’s widely known that their growth rings provide a historical record of environmental events. But are they capable of ‘remembering’? Cutting-edge epigenetic research shows us that there’s far more to this memory narrative than one might initially think.

A tree’s way of interacting with the world fundamentally differs from ours. Nevertheless, these differences do not diminish the importance or complexity of their responses to the environment. Many of the ‘things’ you use in life were ‘once trees’. But did these entities also once have senses and memories?

You’ve been reading an edited extract from Treewilding: Our Past, Present and Future Relationship with Forests by Jake M. Robinson, which is out now. Click below and add the code to buy the book with 25% off.