In this blog post, you will discover 5 secrets about trees. This article is a short review of the book “The Hidden Life of Trees” by Peter Wohlleben. This international bestseller is a mind blowing masterpiece! Even if you’re not a tree lover, you’ll be amazed at the wonders revealed by Wohlleben.

During my extensive investigation in the Miyawaki mini-forests, Wohlleben was a game-changer in my vision of the forests. Many items were then used for our tree plantation and reforestation effort to provide better results. Are you ready for an exciting adventure in secret forests?

In a nutshell, the thesis of this book is: Trees are much smarter than you think. Not just simple pieces of wood. Trees are able to intensely experience their environment and to communicate and share in a social network.

Peter Wohlleben is a forest ranger. He spent decades managing a forest in Germany. He has field expertise supplemented by his investigations into scientific research. I highly recommend purchasing this book from an independent bookstore if you have more time. You will be enthusiastic about Wohlleben’s discoveries, novel ideas and fresh point of view. You will never see trees like before again. If you don’t have that much time, I’ve compiled the main points here for you in a short version. So let’s discover these 5 secrets!

Secret #1 – Trees communicate with each other

Over millions of years of evolution, trees have tested billions of new “technologies” and organizations. They know they have a better chance of survival living together, inside a community, inside a forest.

They need the scale effect to create a microclimate. The microclimate of a forest has dim light and high humidity. This provides cooler temperatures in the summer, as you may have experienced while hiking through a forest.

To secure this forest community, the trees need to grow together. A forest should avoid any gaps in its population or canopy. This disconnection would be dangerous in terms of stormy winds that could uproot trees or heat waves that could dry out the forest.

Bottom line: The trees applied the mantra “Alone, you go faster. Together, we go further”. Working in community with several nearby individuals, trees can create a resilient forest.

So to create a dense community, the trees communicate with each other. The intention is ultimately to warn of impending dangers.

We believe that communication is just one feature of the human or animal kingdom. But no, trees communicate! Not with sounds, but with scents. Trees emit scents to convey a message to the next tree.

Here is an incredible discovery. In the 1980s, research highlighted the community defense system of trees in the savannah. The giraffes there like to eat the leaves of the acacia trees. To protect themselves, the acacia trees pump toxic substances into their leaves to make the giraffes go away. This protection system is slow, it takes about an hour to trigger. So in the meantime the acacias are emitting a gas (ethylene in this case) to warn their tree buddies to get ready!

Other trees like elms or pines even have a smarter defense system. They identify by the saliva the insects eating their leaves. And then they produce scents that attract their predators, especially wasps.

The second powerful communication network is through the roots. Some studies have shown that underground roots extend more than twice the surface of the aerial leaf canopy. Trees produce electrical impulses to send messages to each other through the roots. As a visualization, you can imagine the Tree of Life in the movie Avatar, with visible light messages transmitted to the entire ecosystem through the roots.

Trees also work in cooperation with underground fungi: the mycelium. The mycelium could be thought of as the optic fiber Internet wires, spanning several miles. Scientists even call this communication network the “Wood Wide Web”! A lot of communication passing underground, invisible to our eyes.

Lesson learned: on our Miyawaki method for mini-forests, we want to reproduce this dense and connected indigenous forest. That’s why we prepare the soil to promote root and fungus development. This will result in a dense pack of resilient forests and long-lasting reforestation.

Secret #2 – Trees have their own Social network and can collaborate even with other species

We have been told that trees compete with each other, just as we do as humans. In fact, inside a forest, trees grow inside a larger community in a collaborative effort. We can even say that some trees form a family, with parents and children nearby.

It is commonly believed that trees fight for access to light. Of course, light is necessary for photosynthesis. But not all species need the same amount of light, and some younger trees need to grow at a slower rate to grow strong. Just imagine a Native Jungle where the density is high. Even quite difficult to see the sky with such a thick canopy. All trees, of different sizes, thrive there.

Peter Wohlleben says that “young” beeches can wait over 80 years in the shadow of their 200-year-old “mother”. Once their mother passes away, it’s time for them to flourish and rise.

Tree roots extend in all directions to:

– optimize nutrient uptake

– obtain stability in the ground

– connect with other trees through roots

This network of roots creates a tight and stable underground network.

Trees in regular cases grow straight. They develop their leaves and canopy in their own dedicated spot. When a family member dies inside the forest, it fills in the void and expands its canopy to prevent any holes for burning sun or stormy winds.

Trees also develop their social network, along with other species, to create a balanced ecosystem.

One of the most important interactions is between trees and fungi. They work with a win-win contract. They have a positive association underground. Mycelium can grow inside the fine roots of the tree. It increases the useful surface of the roots and its ability to pump water and nutrients.

Mushrooms develop an impressive underground network. As seen previously, it is used to exchange a large number of nutrients and information. The trees repay them by supplying the fungi with sugars and carbohydrates.

Trees can be a good food source for many species. Parasites in particular, which the trees try to slow down by producing repellent substances. These pests can then be eaten by ants, ladybugs, bees, wasps or caterpillars. This generates a complete food chain in a balanced ecosystem.

Shrubs, shoots or even young saplings can be eaten by roe deers and stags. That’s why we protect our Miyawaki mini forests with fences when planted into the wild. Young trees are candy for deers!

We can therefore see that trees play a key role in maintaining biodiversity, to form a balanced ecosystem. Wohlleben mentions that on the top of a 600-year-old tree, 2,041 animals of 257 different species have been counted!

Lessons learned: this principle of collaboration between species is used in the Miyawaki method with the multi-layered forest. Various species of trees are planted together. They do not grow at the same rate and at the end of the climax evolution they will mature in 4 different layers: shrub, subtree, tree and canopy. The tight and stable underground network will provide a healthy soil for tree growth. And that’s the goal: to achieve a thriving Miyawaki forest that will become a haven for biodiversity.

Secret #3 – Trees optimize energy as a community and can share food

Let’s continue with a true story by Peter Wohlleben. In the forest he managed, he got used to see some stones covered with moss. One day, Wohlleben stopped to investigate. Uncovering the moss, he discovered that it was actually tree bark! Indeed, a hard stump from a fallen tree hundreds of years ago. With his pocket knife, Wohlleben scratched and discovered green material. Green is only related to chlorophyll. This stump was still alive! But without leaves for photosynthesis, the only explanation is that nearby trees were sharing nutrients with this mother tree, through the roots.

Once again, trees have understood that they are stronger together. Their goal is to build a dense community to achieve a resilient forest. For this, the trees help each other. The community helps the skinny saplings in need and even the sickest trees, as they can be useful to the group in the future.

Two examples are good to show that dense native forests are more productive.

Native beech forests are super crowded, with trunks tightly packed together. With such a pattern, it is difficult to move inside the forest. The wood production industry has therefore developed an alternative path. It manages forests with a lot of space between the trees for the reason of stimulating the growth of the tree but in fact mainly to be able to use large cutting machines. By doing so, you create a field of isolated trees, which lose community benefits, with a reduced lifespan.

The second example is the extreme case. I’m sure you’ve seen lone trees artificially planted around town, in big buckets or even in parking lots. These trees are lonely, constrained and clearly looking skinny. Not as healthy as a real forest tree.

A main element of energy consumption and optimization is reproduction.

Conifers produce a large amount of pollen each year, which is dispersed by the wind. But hardwoods produce acorns. Deer and wild boar eat these acorns because it is really rich for their development. The hardwoods have therefore developed a trick to prevent all their acorns from being eaten by a large population of deer and wild boar. They only produce acorns every three or five years. Animals experience starvation due to scarcity and this regulates the population. When the acorns return a few years later, there are fewer animals to eat them. A smart solution for a balanced ecosystem, isn’t it?

Finally, trees carefully optimize their energy: for growth, for the production of repellent substances and for flowering. When it is breeding time, they reduce the amount of leaves produced.

Lessons learned: inspired by indigenous forests, we plant 3 trees per square meter in our Miyawaki forests. It allows to create a dense sharing community as Nature does.

The second element is that Nature always finds the balance. So after 2 years of maintenance removing weeds, we no longer touch the forest, we let Nature do its work. As Dr Akira Miyawaki said of his forest: “The best management is the absence of management”.

Secret #4 – Forests have a capacity of adaptation and they are able to move!

In their forest environment, trees have to deal with perpetual changes.

First, they have to manage natural disasters such as:

– Drought

– Gale, tornado or storm

– Powerful rain or flood

– Heavy snow

For example, in the event of a lack of water, trees will reduce their consumption and develop a protective countermeasure by thickening the waxy layer of their leaves.

Trees learn from all of these unique experience events. Then they pass on this knowledge through genetic material to get better-fit children, with suitable characteristics on the roots, trunk, branches and leaves.

As always, trees take their time to grow and reproduce. Adaptation with generation iterations is therefore slow. Especially when the breeding cycle is every 5 years.

And this is the current problem of climate change. The changes are so rapid that the trees cannot keep up with the adaptations. This is the case with tree species like spruce that have been planted at low altitudes or in warmer climates. With the current increase in temperature and drought, they are vulnerable to pests such as bark beetles.

Secondly, forests are seeing the arrival of new species of trees, imported by man. Usually, these new species are imported because they grow faster than native species. This could become a danger to native species. However, when the ecosystem is resilient, stable and sufficiently mature, the new species will not take over.

Third, the forest has a great capacity to adapt to climatic conditions. With the great genetic variety and the way the seeds travel by wind or birds, the new generation can settle down a little further away with better local conditions. So it is certain that the Forest does not walk like in the Lord of the Rings. But they migrate slowly. This is what has been done to survive climatic variations and ice ages so far (but over a much longer period).

Beech forests are found from Sicily to southern Sweden. In the future, they will move North.

Lessons learned: in our Miyawaki tree plantations, we only select native tree species. The native species adapt best to local conditions. In the next phase, we are also studying species that are already suffering from the current rapid climate change.

Secret #5 – The forest can generate its own micro-climate and can also change the weather in remote places

A forest has significant positive impacts on two dimensions of the environment: soil and atmosphere.

The tree and the soil definitely work in synergy. Healthy soil allows trees to form a complex web of roots. Trees get the proper nutrients through the roots. In return, the roots of the tree provide a stable structure to the ground. It avoids erosion washout during heavy rains.

The forest is one of the best “tech” for CO₂ capture. Thanks to the activity of the tree and then also of the soil. In its lifetime, a tree will act as a CO₂ vacuum cleaner. When the tree dies, this stored carbon will be transferred to the soil. First, the worms will eat the trunk. The rain will continue to transfer into the ground. It will slowly decompose into humus. Small underground organisms will continue the work.

The forest floor is also a huge reservoir of water from all the rains. In all the humus and in the different soil layers, it can store a gigantic amount of water. This reservoir will be used by the roots of the tree in future periods and also for the complete water cycle.

On the other side, trees also help the soil as a thermal regulator. The tree canopy acts as a roof. It prevents the soil from drying out both due to the scorching sun and the airflow. The trees keep the air humidity and the temperature cool to avoid drought. Through evaporation with the leaves (the actual transpiration of the forest), the trees produce even air conditioning and cooler temperatures. This explains the micro-climate you can experience inside a forest in a hot summer.

And here is the wonderful advantage of trees on a larger scale: the transfer of rains to the continent! Clouds form over the seas and are pushed inland. When this rain hits the forest, then the tree with evapotranspiration will generate new clouds which will be pushed further towards the mainland.

The forest acts as a pit-stop or transfer point for the rains to move within the continents. That’s why we need forests from the seaside to the continent to avoid drafts inside the mainland! This water chain is vital and we need the forests to make it work.

Lessons learned: with the Miyawaki method, we take care of the soil first because it is the healthy base of our plantation. Particular attention is paid to microorganisms and earthworms. When planting on barren land or for a urban forest, this is crucial. Using only nature-based solutions, of course!

With this explanation from Wohlleben, we see the impact that the forest can have on CO₂ capture, temperature and the water cycle. So let’s rewild our future with reforestation!

Conclusion

The book “The hidden life of trees” by Peter Wohlleben is a pleasure to read. Entertaining, with practical examples and great stories, it offers an impressive insight into the wonders of a forest.

For me, this has been a nice additional piece in my investigations into afforestation. It supported the Miyawaki method approach. Miyawaki first started studying natural ecosystems before doing any reforestation. So far, Man has used planting techniques adapted to the production of the timber industry. But I am convinced that for natural forest restoration, we can do so much better.

Nature has billions of years of experiences ahead of us. As we see with this book, trees are much smarter than we think. Mainly because they’ve tested billions of different ways to thrive, before us. So if we want to act in this time of rapid climate change, we must first study Nature. Bio-imitate it. Copy/paste what really works. So let’s take inspiration from Nature!