It’s Not Easy Being Green

This is my second post on The Hidden Life of Trees, by Peter Wohlleben. It more or less covers chapters 5 through 8, though I also get sidetracked by discussions of Plato and anthropomorphism, topics (no doubt wisely) not covered in the book.

A Last Hurrah

Even without fire, extreme drought is deadly to trees. Their defenses run down and they become highly susceptible to insect attacks.

What’s surprising, however, is how they react. Under these pressures many bloom the following year. Wohlleben writes:

We know from times of high forest mortality that is usually the particularly battered individuals that burst into bloom. If they die, their genetic legacy might disappear, and so they probably want to reproduce right away to make sure it continues.

Even if it makes a kind of Darwinian sense, it seems oddly desperate or even poetic. It has a whole “one last hurrah” vibe to it. But perhaps I’m anthropomorphizing. If so, I’m in good company.

Arboreal Anthropomorphism

A friend of mine said, correctly I think, that Wohlleben tends to anthropomorphize in his book. When he attributes desire to a tree, he seems to be indicating that the tree is using emotion or logic to determine its next steps. In other words, he makes the tree sound as if it’s a human being.

Personally, however, I’m fine with this because trying to “write around” this issue would make his work read like a text book, replete with passive voice, wonky syntax and sterile language, all in an effort not to attribute human characteristics to trees. That strikes as me unnecessary for two reasons. First, we all know that trees aren’t human beings and that this bit of writerly shorthand is not necessarily to be taken literally.

Second, and perhaps more important, we still don’t understand trees. This is, in fact, one of the key themes of the book. We don’t know how the trees are able to do all the things they do. In many cases, we literally don’t know the degree to which they are and are not like us. In the absence of such knowledge, I don’t think we should get hung up on these issues. Save it for the scientific papers.

So, with those caveats in place, let’s anthropomorphize some more.

Tough Tree Love

Trees are very controlling parents. When a young tree takes root beneath the canopy of a parent tree, it is literally overshadowed for decades and often longer. Wohlleben notes that only 3% of available light gets through to the young tree, causing it to grow very, very slowly. From our perspective, this sounds like an extended juvenilization and a dysfunctional degree of tough love.

But it makes sense to the trees (or, at least, many species of them). Because of the slow growth of the juvenile trees, their “inner woody cells are tiny and contain almost no air” and this makes them more flexible, resilient, and resistant to fungus, insects and other threats. That which does not kill a tree apparently makes it stronger. Nietzsche would approve.

Plato’s Trees

You may remember that the Greek philosopher Plato had a theory of forms. This posits that only ideal forms encapsulate the true and essential nature of things whereas individual cases of those forms cannot live up that essential nature.

Referring to the theory of forms, Wikipedia explains, “We recognize a tree, for instance, even though its physical form may be most untree-like. The tree-like nature of a tree is therefore independent of its physical form.”

But maybe it’s the other way around. That is, maybe individual trees do not reflect the ideal tree in some imperfect form. Maybe the ideal tree stems from the very real needs of individual trees. Wohlleben writes:

This is what a mature, well-behaved deciduous tree looks like. It has a ramrod-straight trunk with a regular, orderly arrangement of wood fibers. The roots stretch out evenly in all directions and reach down into the earth under the tree….[T]here is a good reason for this ideal appearance: stability….Evenly formed trees absorb the shock of buffeting forces, using their shape to direct and divide these forces evenly throughout the structure.

Of course, not all trees wind up looking like the ideal, but they tend to have a better chance of a long and productive life if they do. So, evolution not only shapes the trees but our very ideal of trees–and perhaps even our inherited sense of what is and is not beautiful in the natural world.

The School of Hard Knots

Trees adapt. Or do they learn? What’s the difference?

I’m not going to take a stand on the question, but I will say that they definitely adapt and sure as heck seem to learn.

And its not just trees but other plant kin as well. Let’s start with mimosas. You may have experienced them before. They’re the plants that close their feathery little leaves when you touch them. I still remember the first time I encountered them because they seemed like some hybrid between a plant and animal. But, no, they’re just plants that react a bit more quickly to stimuli.

Dr. Monica Gagliano wanted to see if mimosas can learn, so she “designed an experiment where individual drops of water fell on the plants foliage at regular intervals.” At first, the leaves closed up whenever the drops hit, but then the plants determined that the water wasn’t going to harm them and so remained open even when droplets fell.

Is this learning? Maybe. But it gets more interesting. When Gagliano checked again weeks later, the plants somehow remembered their lesson from weeks before and didn’t close up when the droplets fell. If this isn’t learning, it’s hard to know what else to call it. Now how a brainless plant learns is not clear, but that’s for a different post.

For now, let’s go back to trees. It turns out some trees are spendthrifts and some are frugal when it comes to water. The spendthrifts are the ones with easy access to water and they use a whole lot of it. But they are also the ones hit hardest by droughts because they don’t know how to conserve. They can suffer badly as their wood dries out and this can result in major tears in their bark, opening them up to all kinds of ills such as insects and fungi.

But they can learn to be thriftier. Wohlleben writes that such tree often “takes the lesson to heart, and from then out it will stick with [a] new thrifty behavior, even when the ground has plenty of moisture–after all, you never know!”

So, can a tree be redeemed, having learned from it’s improvident ways? Perhaps so. Maybe there’s hope for all of us.

Featured image: Beech tree with frost crack bark damage, Stacklawhill. Rosser1954. https://commons.wikimedia.org/wiki/File:Beech_tree_with_frost_crack_bark_damage,_Stacklawhill,_North_Ayrshire.jpg