Woodland Park Zoo

After I wrote about the Paperbark maple, I remembered something that I read recently. I think it was a couple weeks ago, when I was flipping through tree books at a used book store. There was a caption that went something like this: Branches that grow at an angle are weaker than branches that grow horizontally.

Or, to quote a master’s thesis1 that I just found online and skimmed in hopes of confirming this notion:

V-shaped crotches … were significantly weaker than U-shaped crotches for all species [tested].

Quick reminder that we’re still talking about trees.

Okay, so I had expressed how much I dislike the Paperbark’s tendency to grow branches that are awkward. Branches that kind of have a U-shaped crotch but then suddenly bend upward, rather than continue out in a way I’d expect. But this judgement is based purely on aesthetic pleasure, despite the fact that I, as much as the next designer, respect the design principle that form follows function—appearance extends (or ought to extend) from purpose.

I thought I’d pull up that industrial maxim, contort it, and apply it to trees. But then, much to my surprise, I learned that the principle happens to be based on the natural world. In 1896, architect Louis H. Sullivan wrote a short essay about the “tall office building”, in which he considered how sections of the early skyscraper should be developed.2 To describe a formula for the various parts of these new buildings, and reject a common, one-method-fits-all approach, he looked outside.

All things in nature have a shape, that is to say, a form, an outward semblance, that tells us what they are, that distinguishes them from ourselves and from each other.

And then he gave us the famous phrase:

Whether it be the sweeping eagle in his flight, or the open apple-blossom, the toiling work-horse, the blithe swan, the branching oak, the winding stream at its base, the drifting clouds, over all the coursing sun, form ever follows function, and this is the law.

Now, nature’s inherent truth doesn’t invalidate every opinion. If a plant looks weird to you, don’t plant it. But through this, I may have found a way to Stop Worrying and Love the Branch. Because what if the very parts of the Paperbark that I think look so wrong are, structurally, so right. What if the tree’s peculiar bends actually make it sturdier than other maples, like an Acer circinatum3 or palmatum4, which are comprised largely of V-shaped connections and which I would normally describe as superior in terms of visual appeal. You know, maybe Acer griseum curls up its arms as if to flex—so confident in its form because of its function.

Well, I’m not going to get a master’s degree just to find out. And, spoiler alert, it’s really the ratio of branch-to-trunk diameter that ends up being more important than crotch angle anyway. But! I will go ahead and move what I had considered a con into the pro column. Because even if this is wishful thinking, the law’s on the books. 

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