This question deals with the magic explained in this question. It is also explained below.

In my fantasy novel, magic is a natural part of the world. It is not some mystical force shrouded in mystery, but rather backed by science (though only I, the author, know all of it's workings).

In my world, magic is a force that by its nature changes living cells. It is similar to radiation, but different in the respect that it changes what the cell does, usually in a beneficial way. For example, if the cells of an eye were exposed to magic, the magic might make the eye also see infrared light.

There are those in my world who can control the change worked by the magic. (They can force the magic to make the eye see infrared light. They can also use magic to make that same eye go blind.)


I've already ascertained that magic-wielders would be able to grow trees into nearly any shape they wanted, including houses (see the linked question). What I am now curious about, is how the magic-wielders would go about making 'windows' in those tree houses. I am not certain how a tree could be altered to produce something relatively small, thin, and transparent, and yet sturdy enough to keep rain and cold out, and heat in. Currently, I've gotten as far as some sort of transparent leaf, but aside from not being sure if a leaf would work grown over a gap in the trunk, I'm not sure if it can be made transparent in the first place.

How could a tree be altered to grow something functionally similar to a window? I don't necessarily need the window to be open-able, though that would be a nice side-benefit if possible.

Note for clarification: This question cannot be answered simply by 'it's magic!' The magic cannot do anything. It can alter living cells to do things they normally wouldn't, but are still possible within the natural world.

  • $\begingroup$ your plant cells can mimic cephalopods such as octopus which have chromatophores to camoflage, I'm saying you don't need windows instead have the millions of billions of pigments to paint the real time scenary on your wall! if you insist on "genuine window" check out thigmomorphogenesis in short your leaves can "shut" or "open" when stimulated chemically or other means. $\endgroup$
    – user6760
    Commented Jul 7, 2015 at 2:53
  • $\begingroup$ As it does not answer really your question, I post it as comment. Please note that earlier castles did not have close windows. It was often just left opened, or closed with wood shutters or thick curtains. See that page. $\endgroup$ Commented Jul 7, 2015 at 5:50
  • $\begingroup$ I'm not sure if you want slightly tinted 'glass', but what about an amber window? $\endgroup$ Commented Jul 7, 2015 at 16:01
  • $\begingroup$ @HadesHerald Amber could probably work, but as I understand it, Amber takes a long time to form. Wouldn't there need to be some kind of structure to hold it in place during that time? $\endgroup$ Commented Jul 7, 2015 at 16:46
  • $\begingroup$ You have the plant produce the sheet if sap inside itself then pressurize and dehydrate it, still going to take between a week and a month, but not bad. $\endgroup$ Commented Jul 7, 2015 at 17:10

5 Answers 5


I'm assuming that the magic of this world allows the magicians to endow a tree with any capability they desire.


Have the tree collect silicon from the soil and oxygen from the atmosphere. Move the dissolved silicon and oxygen into a special pocket in the trunk of the tree where cells similar in function to animal osteocytes will incorporate the silicon and oxygen into a thin matrix resembling bone. While making the matrix, the osteocytes could easily include voids in the matrix to increase its insulation power but at the expense of transparency. (You might be able to handwave the size of the voids to be small enough so they don't interact with light passing through.) After the matrix is complete, the tree peels back the bark and phloem to expose the silicon window. This should be extremely resilient as quartz melts at around 1700°C.

Basically, you're growing miniature geodes within the bark of a tree.

Keep it clean

As an added bonus, have the tree grow a superhydrophobic layer on the outside of the window. No cleaning required and definitely waterproof.

Open and close

Venus Flytraps are well known for closing quickly when a fly lands on their leaves. A similar mechanism could be used to open or close the window.


You might be able to have the tree construct something like nanocellulose. A sufficiently skilled person might be able to get a tree to produce cellophane as well, since cellophane is produced from cellulose. Or, if perfectly transparent windows aren't all that important, a thin, brittle sheet of dried sap might do.

There might be some assembly required after the fact: support structures to remove that had been necessary during construction, for example. Like a sheet of cellulose that had been grown for the express purpose of giving the tree sap something to hold onto with while it dried. Or, in the case of cellophane, you might need to have knobs around the windows to attach the extruded cellophane to afterward.


This already exists in our world. Some plants have fenestrate leaves.

[From Latin fenestratus, past participle of fenestrare: to furnish with openings and windows.]

Thos plants have leaves pierced with small holes or window like openings or with hyaline areas so thinned as to be translucent or transparent.


  • $\begingroup$ Welcome to WB.SE. Your answer is relevant, but as it stands now, it is little more than a link. And answerers are expected to provide some context for the links. It could be that the website is unavailable, for example. So we should understand your point fully without clicking on the link. See also the help. $\endgroup$ Commented Jul 7, 2015 at 10:27
  • $\begingroup$ Thanks for your welcome. I have edited my answer. Please let me know if this is an improvement. $\endgroup$ Commented Jul 7, 2015 at 11:26
  • $\begingroup$ To me that looks better. I made some formatting change, and you can modify it again, or revert to your version. Since they look pretty nice, it would be good to have a picture in, but I did not find a picture that explicitely allowed to be placed here. If you, don't hesitate. You might still want to add in a few words and/or sentences, becayse I am not sure everyone is familiar with "hyaline" (I most certainly not). $\endgroup$ Commented Jul 7, 2015 at 11:53
  • $\begingroup$ I think these would definitely work, but I'm not so sure how they would fit into a hole in the bark, thus creating a window. It wouldn't be too difficult to grow a leaf over the hole - but it also wouldn't be too difficult to just push the leaf aside and get in the house. Is there a way the bark could become a leaf to cover a small area? That way the leaf would actually be connected to the rest of the tree on all edges. $\endgroup$ Commented Jul 7, 2015 at 16:59

There are transparent structures grown from living cells. The cornea of the eye, in particular. Is the problem making it thick enough and still transparent?

A non-living deposit made by living organisms are possible, such as seashells and other tests. In particular, look at the material used by diatoms and forams

Diatom cells are contained within a unique silica cell wall comprising two separate valves (or shells). The biogenic silica that the cell wall is composed of is synthesised intracellularly by the polymerisation of silicic acid monomers

Silicoloculinina are glass forams, making a test out of silica. The mechanism for making the shell is different (inside the cell space vs. Outside) so looking at both glass forams and diatoms for examples will give lots of ideas. It seems that depositing silica is something that cells can do and have developed multiple times independently.

I suppose we could create such a thing using bio-engineering, in the foreseeable future.


I couildn't think of anything like that. That was both strong and see-through, though I liked both of ryepdx suggestions.

Alternatively, to function similar to a window, a hole could be left in the tree and a leaf/flower petal is grown to cover the hole and it is able automatically open during the day and closes both at night and when it rains.

Ofcourse this would mean that if you wanted sunlight in then you would also allow the wind in. Also probably wouldn't work that well during the winter. Even though it is technicly impractical, I liked the idea of having something similar to an automatic curtain/shutter. Mixing this with another idea like ryepdx would hopefully fill out any problems.


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