Flying insects are the only moving animals in this world - they take care of pollination.

Adult trees (over 10 years old) are rooted to the spot with very wide-spreading root systems. Trying to transplant a sentient adult tree would result in death.

Trees have the equivalent of all the usual human senses but in all directions. They can speak to each other but only over the same distance that humans could shout.They each have several specialised branches that act like arms complete with 'hands' and 'fingers'. They can pass or throw objects to one another. They can reach the ground easily and their trunks are quite flexible.

In other words they are somewhat like humans whose feet are glued to the ground except that they draw sustenance from the soil and the air and sunlight. Therefore they don't have our digestive system.


On an Earth-like planet, can they develop even a rudimentary technology? Technology has often been driven by war. Trees compete for space. Could they develop weapons?


These trees are evergreen. They require sunlight. Their seeds fall to the ground but they are capable of picking them up as long as they don't get blown too far. The sentient trees grow to about 50 feet (15 metres).

  • 3
    $\begingroup$ Would they need to? No predators, no food issues... why bother? As regards warfare with other trees? That's been going on for millenia. The kind of chemical warfare trees use would be considered genocide, if used by humans $\endgroup$
    – nzaman
    Nov 17, 2018 at 14:20
  • $\begingroup$ @nzaman - I can think of lots of reasons. Fighting off competing vegetation including non-sentient trees and smothering vines. Medicine to fight fungus and wood boring insects. Musical instruments for entertainment. Canals to ensure year-round irrigation, etc. etc. $\endgroup$ Nov 17, 2018 at 14:29
  • $\begingroup$ As I said, they already do the first few, and very well at that. Musical instruments are a possibility, but you'd need the concept of those instruments before the concept of tools to make those instruments. Canals? How? They can't move $\endgroup$
    – nzaman
    Nov 17, 2018 at 14:35
  • 2
    $\begingroup$ Please read the original Ender's Game saga. The first book would be completely unrelated, but the rest of the books are very applicable. An intelligent alien species has sort of symbiotic relationship with intelligent trees. The trees have a language that sounds somewhat like the Ent language from LOTR and can purposefully break off limbs to form tools. War is a means of spreading seeds. They refer to their villages as "forests". Matches a lot of your criteria pretty well. $\endgroup$ Nov 17, 2018 at 20:27
  • 1
    $\begingroup$ They were created that way by the Tree God who made the first tree in its likeness from the dust of the earth. (sound familiar?) $\endgroup$ Nov 17, 2018 at 23:40

6 Answers 6


What needs would a rooted, sentient tree have that could be satisfied by technology? The strongest drive for the development of technology was often the need to survive or lazyness.

  • Do they need cars, phones or computers? Certainly not.
  • Do they need houses to protect themselved from the elements? No, not really.
  • Do they need weapons? The adults cannot move to wage war against each other and if "Flying insects are the only moving animals in this world" then there's no need to defend against dangerous animals.

But what do they need? Water, nutrition and pollination.


They could start by forming their immediate surroundings to hold rain water for a longer time. Some tree will at some point notice that clay holds water better than soil, so he starts building little clay dams.

In theory the next step would be to form clay vessels to hold water, but you would need to burn the clay, a very dangerous endeavor for a tree. Humans could cut down and hollow a tree to make a trough, but would a sentient tree do the same?

Trees growing next to large boulders could at least hollow them out by grinding smaller stones over the surface, but I'm afraid that's as far as they would develop technology in that area.


Trees fertilize their own soil with the leaves they loose to a certain extend. Stealing lost leaves from a neighboring tree would be beneficial for your sentient trees (given they can endure the bickering and complaints of said neighbors). They could develop a technology to extend the range of their branches, but their neighbors would certainly do the same. Next they would need a defence agaist the branch-extensions of their stealing neighbors to keep their leaves around. In the end, it would make fall a very stressful season without any gains and probably without clear winners.

But if they really wanted to extend the reach of their brances, how could they do it? The only material available are their own bodies or non-sentient plants. Their "technology" would probably be no more than the equivalent of a human wielding a tree branch like a broom.


This one depents entirely on the insects on the planet. Most pollineators are attracted by colors in the visible and infrared spectrum, so the most colorful trees would have an advantage.

They could adorn themselves with blossoms of non-sentient plants or other materials that attract insects. Some might even discover simple chemical reactions that produce materials attractive to insects. But in the end, they are limited to the materials available at the surface of the earth or in the air and in reach of their branches.

Family matters?

Last but not least, they could feel the need to communicate over longer distances than naturally possible. If Billy the sapling waves mommy good-bye and plods into his bright future beyond the hill, mommy tree wants to call him from time to time.

Humans had similar problems in the past and came up with different devices like whistles, drums, colored flags and bullroarers.

If Billy the sapling plods his way over the hill and out of the acoustic range of his mommy, she might take a piece of clay and draw her message into it. The trees could develop their own script like Cuneiform, which developed this way as well. Message delivery and adressing over long distances could be a problem, though.


Adult trees (over 10 years old) are rooted to the spot with very wide-spreading root systems. Trying to transplant a sentient adult tree would result in death.

This means they are stuck where they happen to be born. They can rely only on resources they have at reach. Being able to pass each other object is of little help. Whatever they have at reach is single use for throwing. They won't be able to harvest resources which lay underground.

But the most important limitation is the energetic balance.

The first jump for mankind in the race to technology has been the ability of using fire. By using fire our ancestors have been able to extend their operation to the hours with no sunlight and, by cooking their food, to increase their energetic income. More energy available to a body implies more activities which can be executed.

Your trees are bound to sunlight. They can grow peacefully and slowly like a tree does, but as soon as they have to dig few meters of soil to harvest some copper ore or some stone they will run out of energy and become exhausted. Being photosynthetic organism they would not benefit from cooked food. And I suspect that burning other trees to fertilize the ground where they live is going to be suicidal, considered that they cannot move.

  • $\begingroup$ Trees aren't born in the ground. They grow from seeds lying on top of the ground. The younger a tree is, the more possible is transportation. The ultimate in this is of course transporting seeds but saplings could, with care be passed around provided the technology to do so was available. $\endgroup$ Nov 17, 2018 at 14:33
  • $\begingroup$ I suspect that the trees' equivalent to harnessing fire is harnessing reliable water supplies. $\endgroup$ Nov 17, 2018 at 14:36

I think the "rooted to the spot or they die" thing would be about the first thing that would be addressed by technology. As soon as the first tree thinks to collect its seeds into pots so it can move them around to catch the best light, the saplings are mobile.

Then placing the pots onto a sled covered in loam lets the tree move around on its own. The invention of the wheel and carts just makes this easier.

With or without carts, the differences between their technological advancement and ours will be notable, however. I've written the following assuming trees that can see, and have put their seedlings in carts.

They will have FAR lower energy. A human could not live on photosynthesis. This means they must move far less, and likely have far greater reaction times. This would slow progress. However, they live longer, so would get about as much done in a lifetime.

They are considerably more flammable than us, and with slower movement and reaction times, fire would be very dangerous. Fire, and hence pottery and metallurgy, would be slower technologies to develop. Agriculture and all our food-related technologies would no longer be primary concerns.

Herbivores would be seen as predators and would be fended off with simple spears, and perhaps by encouraging and protecting predators. Domestication of animals could also happen with those tree-living animals that don't harm the tree (squirrels, birds) and perhaps they might perform symbiotic cleaning and nutritional services. But the main drive to animal husbandry for food wouldn't be there, though as beasts of burden for transport, it might still happen.

Building walls might be useful for protection, but roofs, stairs, multi-storey buildings etc would be largely unknown since they would block light.

Transport would be a main driver, since they don't have legs. Cart tech and road manufacture would advance quickly. Roads would initially have to be very gently sloped, with switchbacks for any serious hills, but they'd get better fast.

Water travel would need to be done carefully, perhaps with ferry-like ropes running the length of each river, to control speed down to the reaction times of the trees.

Transport accidents could/would leave people rooted to the spot where they crashed, so technology would advance to be able to transplant root-balls without killing the tree, as a matter of emergency healthcare.

Healthcare would involve things like mold, parasites and infestations; re-splicing broken limbs, sealing the stumps of severed ones, etc.

The main cause for wars would be horizontal space, and areas with good sun - so wars would likely happen, perhaps even more than with humans, and would likely involve fire as the main weapon, rather than bladed or explosive things. Though they would also use the tools they use for harvesting non-sentient trees, and the damage you could do with a mere rope trap to sweep people off their carts could be deadly. While they'd be far more stable than people, once they were down, they'd be down.

Cloth would not be needed for coverings, and such light-blocking things would not be seen as useful.

Simple machines - wheels, levers, etc - would still be invented, but an industrial revolution perhaps needs a requirement for things like cloth. Rope might be a necessary-enough thing to be worth making machines for. Also carts, of course.

The theoretical max for Photosynthetic efficiency is around 11%, but plants typically attain only 3-6%. Improving this would be one of their technological focuses. Taking energy from the sun might eventually be supplemented or even supplanted by injections of sugars.

Cosmetics could include, as well as human style clothing, jewelry and cosmetic nesting animals, cosmetic splices from nonsentient flowering trees, etc.

If the trees can't see, that'll add a whole new dimension to the differences.

The concerns covered by Maslow's hierarchy of needs may be worth going through, to figure out what the main concern of the trees would be at the base of the pyramid, and how that would drive their initial research, then the concerns higher up the pyramid as they grew in technology.


If you view technology as the creation and use of tools, then, yes, they could invent these things. When we think of technology we probably first think of fire and metalwork. But these are things that may or may not be available, or desirable, to sentient trees.

One old human technology (though young when compared to fire) is writing. The preservation of thoughts or speech into cultural artifacts. It could start off as marks on wood or clay passed along with a group of collected seeds. If the society is to grow and spread in an optimal way, seeds need to be planted in the right places. Passing seeds until they make it to the edges of the "village" is the easy way, but it would be more efficient to have a plan and to write that plan down so it is followed. After all, the trees at the edges will be younger and less experienced. With proper instructions, this could be done with saplings too.

As the culture evolves, writing would too. They'd develop some rudimentary math. Just counting at first. But later they'd be able to calculate optimal planting methods for different areas. This would also lead to mapmaking.

Paper seems like a technology within their abilities, as it involves turning plant material into a watery paste then spreading it on a flat surface to dry. They could collect charcoal from accidental fires to write with. Later they'd learn to have a few controlled fires to create it.

If they have access to glass, they can improve their ability to see long distances. Something important for scouting out new terrain or predicting weather patterns. Glass is sand plus fire plus some proper containers, so would require some metal work. Or perhaps it could be fire and sand then a lot of polishing of the remaining hunk. Or there could be some naturally-formed crystals within reach.

Predicting the weather or viewing the skies will escalate the development of math. Between this and the importance of reading and writing, they will develop schools (minus the travel) and textbooks and pedagogy.

At this point they'd have fire workers who lived around clearings that allowed them to safely contain fire (near water sources too). Buckets and access to water (bamboo pipes?) would be there as well. Buckets can be wood, made from non-sentient species or from their own prunings, if they prune their old wood or ever lose limbs.

If there is cotton or linen in the area, or some silkworms, they can create fabric. You don't need tools to spin and weave if you have a thousand fingers and lots of time. But those tools are generally wood anyway, so doable with time.

Naturally, one of the technologies that would come out of the basic ones would be farming. Not for food, but for materials to make cloth and non-sentient trees to harvest for wood. Different fabrics and woods will have different uses, so they'll need multiple farms.

Trees will specialize now. Because they can't move, they're stuck in their professions. Though transplanting saplings will be easy now so youngsters can choose their careers. You'll have farmers, craftspeople, fireworkers, water tenders, etc. Some materials can be passed around, so there can be some choice in what one does, but a lot of it will be dependent on where you are rooted.

Communication will evolve as well. Technologies to improve the range of spoken words. Newspapers and novels and poems and other writing. Songs and theater to spread out through repeater trees. They may be able to develop technology that limits where a communication goes. This is essential if you have schools or professional talk or anything else that needs to be limited so there isn't a cacophony of noise all the time that makes it impossible to pick out what you need. Then you get a concept of privacy. And even more tech to make it possible.

How far they can go will depend a lot on what raw materials they have access too, like metal. But there's a lot they can do without it as well.


The question actually falls to definitions. A tree species is far enough from humans that we have to be careful when making the assumption that "technology" means the same thing to all people asking or answering the question. Based on subtle nuances in our meanings for the word, we may arrive at drastically different answers once we stretch them all the way to the trees.

Personally, I find it effective to define technology as something which has three distinct phases. The first phase is a thinking phase, where an individual or a group of individuals think up the technology. They may experiment with physical prototypes and such, but the prototypes will never enter production. The end result of this phase is a document describing how to make the technology. Those who thought it up can look at that document and verify that yes indeed the document describes how to make something that matches what they are thinking of.

Then the thinkers go away. Technology is typically used in such a widespread fashion that we have to bring in a larger group of individuals who know how to make things. These individuals have the know-how to take a document describing how to make something and actually make it. They understand how all the parts fit together. They may also understand why it works, but that's typically a thinker's game. In fact, if the person making it is also the person who knows how it works, the object tends to start to drift into the class of "a work of art," and I typically stop calling it a technology.

Once that is done, the makers go away, and we have the users. Again, technology is a widespread thing. If everyone who used it made it themselves, it gets into a fuzzy region that I often stop calling a technology. The users generally don't know why it works, nor do they know how it works. They just use it.

If you accept this definition (and you aren't obliged to), then for most of what your sentient trees do, its going to be difficult but not impossible to have a technology. Having those two divisions placed in the definition I used mean anything technological is going to have to involve changing of hands many times, far away from the people who originally thought of it. It's plausible that can occur, but it would be hard.

However, there is a twist. What about "technology" produced by previous generations? Consider a tree that figures out a bark design that's better against beetles. It passes that on to its children in DNA form, These children may have no idea that the bark is better, but they can pass it on to their children who use it. The line for "technology" is always fuzzy, and up to the user. Mine happens to have some support for DNA based technologies. Does yours?

  • $\begingroup$ Anything I haven't specified in the question is valid even if it disagrees with what I have in mind. However it may be that someone with a looser definition (that still doesn't break my rules) comes up with a better answer. Passing on better bark by DNA is evolution rather than technology isn't it? Or do you have something else in mind? $\endgroup$ Nov 17, 2018 at 15:02
  • $\begingroup$ @chaslyfromUK It would probably depend on whether the "thinking" process of your sentient trees got to modify the DNA or not, or modify the process of evolution. I think it can be frustratingly difficult to draw a line between a high quality hunting dog and a technology such IBM Watson, which won jeopardy. $\endgroup$
    – Cort Ammon
    Nov 17, 2018 at 15:04
  • $\begingroup$ Well the situation is very much like stationary humans. I don't think we can modify our own DNA by thought. But we can by using technology. $\endgroup$ Nov 17, 2018 at 15:06
  • $\begingroup$ @chaslyfromUK This is where I find it fascinating. Or minds cannot use technology to modify our own DNA without first using our biology -- nerve impulses causing muscles to twitch. Indeed the first technology must have been made without technology. Perhaps the DNA modifying trees must also use their biology to start the process. (This also comes full circle, as we get into cyberpunk where the technology becomes fully integrated with the biology) $\endgroup$
    – Cort Ammon
    Nov 17, 2018 at 15:09
  • $\begingroup$ "the first technology must have been made without technology" Not sure if that applies with flint tools which require one rock hitting another in order to make a blade. See my answer. $\endgroup$ Nov 17, 2018 at 15:28

Flint tools

I've decided to answer my own question as I have thought of a possibility.

Trees living where there is flint lying on or near the surface could fashion flint tools. They could pass or throw these on to other trees. Flint knives would be useful for self-pruning, cutting back non-sentient vegetation and making wooden artefacts such as tree-dolls and musical instruments. They could also carve boomerangs for entertainment. Wood would be easily available from non-sentient species.


Games of catch with complicated rules about who could throw the ball to whom would be fun. They could develop into a sport.


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