On becoming a tree…

“As long as you keep getting born, it’s all right to die sometimes”

Orson Scott Card, The Speaker for the Dead.

I’ve written many times about the differences between autotrophs and heterotrophs on this blog. Loyal readers will know I have a hard-line stance that humans fall decidedly into the heterotroph camp. Nevertheless, some art projects blur the lines between person and plant. So I was more than a little intrigued when a link for the Bios Urn came across my Facebook feed.


The product offers an alternative to the traditional cemetery as your eternal destination. It’s a special biodegradable urn in which your ashes (or a loved one’s or a pet’s ashes) can be placed along with a tree seed. The whole thing is planted in the ground at a cemetery or other special location. The recycled carbon atoms of your body become the growth medium for a tree that will grow and live on after your death.


It’s beautiful. I get it and as someone who often quotes the Lorax, I’m all for any excuse to plant trees. But honestly, the first thing it made me think of was my all-time favorite book The Speaker for the Dead by Orson Scott Card.* Within the world of this book, humans live on a colony planet that happens to have another species of sentient beings called the Pequeninos. These organisms spend the majority of their life cycle as mammal-like beings, but can pass on into a third life as a tree provided they have been vivisected. It’s pretty gruesome and obviously humans don’t work this way, so cultural misunderstandings ensue.

However, because I’m a stickler for scientific accuracy when it comes to plant science (Hey, someone’s gotta be.), I have one problem with the overly simplistic marketing scheme of the Bios Urn. You don’t actually become the tree. For those of you saying, “I know, I know I won’t be a tree, but in the circle of life my molecules will become part of this tree.” I’ll still be over here at my blog shaking my head, “No, that’s not really how that works.” Here’s a reminder of the photosynthetic equation:

6 CO2 + 6 H2O (+ light) → C6H12O6 + 6 O2

Plants accumulate carbon and mass from atmospheric CO2, not carbon ash or even organic carbon compounds in the soil. The truth is that if you planted your ashes with your tree seed, your carbon would still remain locked in the soil for many years until eventually it is metabolized by microorganisms in the soil and released as CO2 as part of their respiration. This is not a very quick way to turn over your carbon molecules, and your molecules have millennia before they ever become a part of any tree. If you truly wanted your carbon molecules to incorporate into some kind of plant matter, then you need to find a way to carbonate your deceased body. Human carbonated essence could be stored in canisters and then used to supply CO2 to your plant of choice. You could be part of that camellia bush in your front yard, your favorite LSU Oak tree, the General Sherman etc. Scientifically accurate, but good luck marketing that compared to cremation.**

All of this highlights a common misconception about photosynthesis- it’s hard to comprehend how mass can accumulate into living things from air. Our gut tells us mass must come from something more substantial. We memorize the photosynthetic equation in elementary school, but few of us grasp its consequences and really believe it.

“This is how humans are: We question all our beliefs, except for the ones that we really believe in, and those we never think to question.”

Orson Scott Card, The Speaker for the Dead

So, when you die, ask someone to plant a tree or something in your memory. Do it for someone else you’d like to remember, but ashes not really required. Or buy a BiosUrn or put the ashes in a degradable coir starter pot from your local garden center, but you’ll probably want to supplement them with some form of NPK fertilizer. It will help the seed more than your carbon atoms.


*It’s a sequel to Ender’s Game for those of you that may not be SciFi freaks.

**Although, in-home soda fountains are a thing now, so if there is a way to carbonate deceased relatives and store them in the handy canisters… well, you get the idea.

Links and References:



3 thoughts on “On becoming a tree…

  1. Trunil

    May be they should advertise saying that your loved one’s nitrogen/phosphorous becomes a tree. 😛
    I am not a regular reader of you blog but I’ve liked all those posts which I’ve read.

    1. johnnaroose Post author

      Thanks! I still like the idea, so I can’t give them too much of a hard time about accuracy. There are plenty of other examples of scientific inaccuracies in advertising.

  2. Pingback: More Forest Numbers and Tree-Planting Drones | New Under The Sun Blog

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