Without trees, our planet and our lives would be dramatically different. Indeed, given the fact our ancestors lived in trees, it’s certain we would not be here at all.
Trees do so much, in fact, that I think we can classify their impact as the Yggdrasil Effect. Yggdrasil, of course, is the immense and sacred tree of Norse mythology. The branches and roots of the great tree connect the various parts of the cosmos. Yggdrasil is not, however, in perfect health thanks to serpents that chew at its roots and stags that chew on its leaves. In short, the great tree–and therefore the cosmos itself–is mortal and under constant threat.
The Yggdrasil Effect highlights both the many essential functions of trees in our world as well as their essential fragility and mortality.
Pumping the World Up
According to myth, Yggdrasil has three major roots that it uses to pump water from three magic springs or wells, presumably pushing those waters to the rest of the cosmos. In real life, trees play a similar role. If it weren’t for trees, in fact, most of today’s dry land would be deserts.
You see, clouds form over oceans (where most of the water is, of course) and then those clouds float over nearby land, whereupon they unleash the rain they contain. Wohlleben writes. “If depended on just this mechanism for water, life would be possible only in a narrow bank around the edge of continents.”
So, what do trees do to pump water into the rest of the world? First, they spread their canopies over the land. After the rain falls, much of it remains in the canopies where it evaporates again rather than just running off back into the oceans. “In addition,” Wohlleben writes, “each summer, trees use up to 8,500 cubic yards of water per square mile, which they release into the air through transpiration. This water vapor creates new clouds that travel farther inland to release their rain. As the cycle continues, water reaches even the most remote areas.”
So, if you happen to live in a place is not near a coast but where you get a goodly amount of rainfall, you can thank the trees.
You may have heard that the world has a carbon problem. Global monthly average concentrations of carbon dioxide have risen from around 339 parts per million in 1980 to 412 parts per million in 2020, an increase of more than 20%. More carbon means more global warming, which means all kinds of bad stuff, including more frequent and devastating forest fires.
But as long as they are not being incinerated, trees are amazingly good at pulling carbon dioxide out of the air and storing it in their bodies. Even once the trees die, much of the carbon is stored underground as they disintegrate into the forest floor. Wohlleben writes,
It’s true that some of this carbon dioxide does indeed return to the atmosphere after a tree’s death, but most of it remains locked in the ecosystem forever. The crumbling tree is gnawed and munched into smaller and smaller pieces and worked, by fractions of inches, more deeply into the soil….The farther underground, the cooler it is….And so it is that carbon dioxide finds its final resting place in the form of humus, which continues to become more concentrated as it ages.
If we could just stop burning all the ancient carbon that is stored below ground in the form of carbon-rich fossil fuels, then eventually the trees could capture much of the carbon in the air and once again cool down our ever-hotter planet. It’s nice to plant more trees, of course, as a way of vacuuming and storing carbon, but it’s even better if we can leave the older trees alone to do their thing. The larger tree, the more quickly it grows in terms of total biomass, thereby sucking up more carbon.
Controlling the Climate (for Reals!)
Controlling the weather has long been a trope in the world of fiction. (Typically associated with carton villains: Simon Bar Sinister anyone?) In the real world, we haven’t gotten very far with weather control aside from some cloud seeding. On a larger scale, of course, there’s the climate, both global and regional. We’ve been affecting climate via our massive global bumbling with greenhouse gases, but this is a case where we’ve changed it for the worse for our own species (not to mention so many species).
Trees, however, have a much better track record in this area, able to create their own climates, both macro and micro, for their own benefit. We’ve already discussed the macro aspect of pumping water all over the planet (which obviously serves the need of trees as well as humanity). But trees are also pretty good at affecting climate on other scales. Wohlleben provides the example for a little forest of beech trees.
With their annual leaf fall, the beeches created an alkaline humus that could store a lot of water. In addition, the air in this little forest gradually became moister, because the leaves of the growing beeches calmed the air by reducing the speed of the wind blowing through the trunks of the pines. Calmer air meant less water evaporated. More water allowed the beeches to prosper…
In short, the beeches became part of a positive feedback loop, helping to create an environment in which they could thrive. Now that’s an excellent case of climate control.
Beneath the Arms of Giants
Wohlleben also refers to tree-driven “microclimates.” When I read that, I could immediately relate. We have an oak tree in our front yard, which feels so different from our back yard that they might as well exist in separate dimensions. Whereas the front yard often feels cool and moist even in the heat of the summer, the back yard feels parched and blazing hot, especially in the summer. In the Florida winter, the temperature is somehow more moderate under the tree, a characteristic that made more sense when I learned, according to Wohlleben, that “trees sweat.”
Huh. So that’s why our cars don’t get frost on their windshields in the winter as they did when we used to parked them on a treeless corner in the same city. They’re kept warmer under the giant, radiating, sweaty tree. I’m not sure if that’s gross or comforting. Maybe a bit of both.
Of course, I was perfectly aware that parking under a tree is messy, though I never quite considered it was because trees shed bits of bark and sticks in the same way we human beings shed our skin (which is where so much of the dust in our houses come from–I know, ew).
In short, trees are literally the moist, smelly, sweaty, shedding giants in our midst, so big that they create the micro-climates in which we live. I suppose we know that at some level. On another level, however, we often tend to see them as inanimate things such fences, pillar, streetlights and the roofs of houses. Maybe that’s because we hold their lives in our hands. Viewing them as beings rather than things means we have responsibility for these giants on whom we so depend. It’s a lot of pressure. I suspect many of us would rather not think about it.
Note: This post covers some of the material in chapters 16 to 18 in The Hidden Life of Trees.
Featured image: The norns Urðr, Verðandi, and Skuld beneath the world tree Yggdrasil (1882) by Ludwig Burger. https://en.wikipedia.org/wiki/Yggdrasil#/media/File:Die_Nornen_Urd,_Werdanda,_Skuld,_unter_der_Welteiche_Yggdrasil_by_Ludwig_Burger.jpg