The Thammasat University Library has newly acquired a book that should be useful for students interested in ecology, biology, forest conservation, and related fields.

Finding the Mother Tree: Discovering How the Forest Is Wired for Intelligence and Healing is by Professor Suzanne Simard, who teaches in the Department of Forest and Conservation Sciences at the University of British Columbia, Canada.

The TU Library collection also includes other books about different aspects of forestry.

Professor Simard explains that trees are “linked by a system of underground channels” that create a “forest society.

Older trees are able to identify the younger trees that they are related to, and try to protect these younger trees.

In this way, a so-called Mother Tree transfers nutrients to younger plants.

Through laboratory experiments, she has also established that birch and fir trees communicate with each other.

Some specialists have objected that by comparing trees to humans, she has imposed human values onto a non-human system.

Instead, they recommend that it might help nature more if we can accept that trees and other forest plants are unique living things, not necessarily like humans in behavior.

Few dispute her argument that current forestry policies are not successful.

Professor Simard also suggests that humans can learn from forest ecology how to regulate their own conduct.

Her Mother Tree Project, set over nine sites in British Columbia chosen for their range of altitude, geology and climate, she aims to establish the science that will support a new forest management style encouraging collaboration as well as competition.

She links this work to the management of global carbon dioxide levels and the battle to control increasing global warming.

The introduction to her book states:

This is not a book about how we can save the trees. This is a book about how the trees might save us…When Mother Trees — the majestic hubs at the center of forest communication, protection and sentience — die, they pass their wisdom to their kin, generation after generation, sharing the knowledge of what helps and what harms, who is friend or foe, and how to adapt and survive in an ever-changing landscape. It’s what all parents do.

In 2021, she explained to National Public Radio how trees can help each other by sharing nutrients:

[At the time] birches were considered weeds. There was a huge program to spray and herbicide these trees to get rid of them because the foresters viewed the birches as competing with Douglas fir, competing for light especially. I was observing in these plantations, though, that when they weeded out the birches, when they sprayed them or cut them, that there was a disease in the forests that would just start spreading like a fire. It was called Armillaria root disease. I really thought, we’re doing something wrong here. And so I wanted to know whether the birches were somehow protecting the firs against this disease and that when we cut them out it actually made it way worse.

I had learned about these mycorrhizal fungi and how they could actually protect trees against diseases. And I’d also heard about David Reed’s work in the U.K., where he had shown that in the laboratory that trees could be linked together by mycorrhizal fungi and pass carbon between them. So I tested this between birch and fir in my sick plantations.

I planted birch and fir and cedar together in little triplets. … And I traced how those carbon molecules went back and forth between the birch and fir and they didn’t actually end up in the cedars. Because the cedars, they form a different kind of mycorrhizal fungus that doesn’t associate with either birch or fir. So [the cedar] wasn’t actually in the network with birch and fir, and it picked up hardly any of this isotope.

I knew that birch and fir were sharing carbon below ground — much against the prevailing wisdom that they only compete for light and also that the more that birch shaded Douglas fir, the more carbon was sent over to Douglas fir. So there was a net transfer from birch to fir that was sort of mitigating its shading effect.

In this way the ecosystem was maintaining its balance — the birch and fir could coexist because of this collaborative behavior that was sort of offsetting some of the competition that was going on. […]

[Trees] get old. They do eventually decline. And dying is a process, and it takes a long, long time. It can take decades for a tree to die. In the process of dying, there’s a lot of things that go on. And one of the things that I studied was where does their energy — where does the carbon that is stored in their tissues — where does it go? And so we label some trees with carbon dioxide — with C13, which is a stable isotope — and we watched as we actually cause these trees to die. We stress them out by pulling their needles off and attacking them with budworms and so on. And then we watched what happened to their carbon.

And we found that about 40% of the carbon was transmitted through networks into their neighboring trees. The rest of the carbon would have just dispersed through natural decomposition processes … but some of it is directed right into the neighbors. And in this way, these old trees are actually having a very direct effect on the regenerative capacity of the new forest going forward.

This is a completely different way of understanding how old trees contribute to the next generations — that they have agency in the next generations. And our practices of salvage logging to get rid of dying trees, or trees that have just died or have been burned in wildfires — if we go in and cut them right away, we’re actually short-circuiting that natural process.

Our studies suggest it would have knock-on effects to the regeneration coming up. They’re not going to be as well prepared for their lives coming forward. So I’ve been trying to tell people: Let’s hold back on this salvage logging until trees have had the chance to pass on this energy and information to the new seedlings coming up.

(All images courtesy of Wikimedia Commons)