The Hidden Life of Trees

From the time Tim Flannery made my jaw drop moments into the Foreward  I was totally in love with this audiobook.

If a giraffe starts eating an African acacia, the tree releases a chemical a chemical into the air that signals a threat is at hand. As the chemical drifts through the air and reaches other trees, they "smell" it and are warned of the danger. Even before the giraffe reaches them, they begin producing toxic chemicals. 

Wait. What? Trees can sense that a giraffe is eating them and respond to it? Wow. And trees can talk to each other to warn their neighbours of pesky giraffes?? Perhaps I'm just completely ignorant but my mind was well and truly blown.

Trees are with us every day, but their apparent motionless state blinds their lives from us, they are hidden in plain sight. 

Peter Wohlleben really opened my eyes to these seemingly silent sentinels of our world. Trees live on a different, much slower time scale compared to us, our human lives so much shorter then their lives played out over centuries when living in a forest. And so we don't see them as the social beings they are. Peter explains how trees feel pain, how they communicate, and how they nurture and support each other. It not only takes a village, it also takes a forest. Trees in a forest will support the sick and dying, and even nourish "dead" tree stumps. Peter anthropomorphises trees and talks of families, relatives and friendships. It was all a complete paradigm shift for me, and with every new chapter another new shift came.

Even the things I thought I knew about trees (but hadn't thought about in decades) were wrong. Like most people I was taught in biology at high school and uni that water moves in trees by a combination of capillary action and transpiration. Peter takes just a few moments to explain that neither of these forces are anywhere near adequate to explain the movement of water up a tree. You know what? We don't even know. We don't know how water moves up a tree! Science, technology and medicine have made our lives comfortable and healthy on the whole, we have explored the far reaches of our planet, and our own moon, but we still don't know how water moves up a tree. It's almost unbelievable. 

I had never even really given much thought to the fact that trees are green. I know well enough that trees have chlorophyll to absorb light and that white light splits to give us a rainbow of colour. So Peter asks us why aren't trees black?

Chlorophyll helps leaves process light. If trees processed light super-efficiently, there would be hardly any left over- and the forest would then look as dark during the day as it does at night. Chlorophyll, however has one disadvantage. It has a so-called green gap, and because it cannot use this part of the colour spectrum, it has to reflect it back unused. This weak spot means that we can see this photosynthetic leftover, and that's why almost all plants look deep green to us. Beautiful for us; useless for the trees. 

Even more amazingly some trees have red leaves because of a metabolic disorder. 

Young developing leaves on normal trees are often tinged red thanks to a kind of sun block in their delicate tissue. This is anthocyanin, which blocks ultraviolet rays to protect the little leaves. As the leaves grow, the anthocyanin is broken down by the help of an enzyme. A few beeches or maples deviate from the norm because they lack this enzyme. 

There is just so much in this book, not all of it about trees. Trees have very close codependent relationships with fungi (fungi can take up to a third of a trees food production), and they are in a life and death struggle against the fungi for their entire lives too, so there's quite a bit about fungi in the book Fungi form the largest lifeforms on earth! Of course other creatures are mentioned too- the birds and insects that live in the trees, the many and varied life forms that feed off trees when they are alive and when they are dead.

It's almost too much to take in. So, as I often do, I listened twice through, and then borrowed the book from the library to see if I had missed out on any visual content. The book is illustrated with a few simple, yet beautiful, drawings by Briana Garelli. 

Peter Wohlleben is German and manages a forest in Germany, so naturally his specific knowledge is about the trees and forests of Europe. I'm not so familiar with European trees, yes I can recognise an oak tree, or a spruce, but I don't know many of the trees he talked about all that well. I would love to hear a similar book about our Australian native trees.

The translation by Jane Billinghurst (a writer and gardner herself) is absolutely beautiful, the book reads like an English language text, not at all like a translation from the German.

Highly recommended.