How could a large (10,000-20,000 people) elven city hide itself from a person wandering through? These elves can bend plants to their will and stimulate plant growth by singing, so they could live in magically altered trees. However, they need a reliable source of food and water, a place to put waste, and solutions for all the other problems cities have. What would keep the city hidden from people in the vicinity?
Some ideas for the elf city. 1. These elves are small and camouflaged, like these little people.
- The "city" is a cypress forest. The entire forest floor is slowly flowing water. Poop etc is not obvious because it falls in the flowing water.
this image found at https://www.flickr.com/photos/siennapictures/4892726816
The elves live inside the trees which are partly hollow and up in the crowns. There are minimal if any built structures. Travel is from tree to tree, like monkeys. When we see images of the cypress forest it is open places where people can go, but you could have ground level be essentially impassable with brush, quicksand and cypress knees blocking boats.
The elves can eat leaves and fruit and raise birds and bromeliads in the treetops. Maybe they eat an occasional fish or crustacean from the waters below.
An acre per individual is generous - I have to think that a football field worth of trees could support one little elf. That is not much population density. 10,000 acres is 15.6 square miles or a square 4 miles on a side. 10 elves per acre is 1.5 square miles. If these are good big trees the size of mango trees that is still fine. Plus the elves can sing the "stay in fruit all year" song to them.
Really this city is a bunch of elves living in a forest. Anyone entering the city would be traveling over water and would make some noise. The elves are quiet when anyone shows up.
Well, according to this site, the town of Antrim in Northern Ireland has a population of 23,353, which is a little bit higher than your higher estimate. A quick look on Google maps suggests the town is about 6 square miles.
That's a whole lot of city to hide completely. Even if you assume the houses are built of living trees someone walking through is going to notice something isn't right, and that's before we even consider where they get their food or water from or what happens to their waste.
So probably the first step to hiding it is to put the city somewhere people are not likely to go. It should be far off the beaten path to reduce the chances of accidental discovery. Then you need to deter people from coming to the area at all, probably by spreading rumours and legends of the forest being haunted (which can be backed up with a bit of tree magic perhaps, some eerily shaped trees on the outskirts or people actually being attacked by trees upon entering should help support the legends)
Having done this it may be better to actually spread the city out more so that any patterns among the houses/buildings etc. are less noticeable to anyone who does brave the forest. It does depend on whether the elves live in shaped trees or in houses made from trees (which would probably be a lot more obvious if they are house shaped rather than tree-shaped) too.
All in all, I'd say you would have quite a bit of trouble hiding a settlement of that size completely.
Probably quite easy - have you ever tried to walk off the beaten path in a dense forest? It's really hard going. So if you're on holiday and just sort of roaming, you'll tend to follow established trails.
And if you're going from A to B through the forest, you'll do the same, especially with a wagon or similar.
So the answer is a quite simple one - stay away from the established trails, and ensure there's enough annoying undergrowth to block people from 'straying'. Brambles are perfect for this - they grow fast, and they're irritating and tedious to hack your way through (and obvious, so you can intercept/divert).
Lines of sight in dense woods aren't all that long - so all you need do is ensure the 'city' is far enough off the 'standard' trails, and have rangers to patrol and ensure no paths - or easy routes - to the city exist. And that the paths you want people to follow stay clear enough that they're not tempted to make their own.
As the other answers have picked up on, you have kind of provided an answer already by stating that the elves have the ability to manipulate plantlife. Provided that at least some of their woodland plants or fungi can produce something edible (to the elves), this takes care of their food supply and probably to a large extent, the way to hide their 'city', so really, this just seems to be about fleshing that out a bit?
So how about this:
The elves live largely underground, or more specifically in the partially hollow roots of trees, which if the trees are large enough, would be absolutely massive, especially with the help of the magical elves. Also, the roots of the trees could easily be linked across a vast, VAST area. There are a number of real world phenomenon that would support this as a possibility. Plants (and fungus) can and do connect in a process called grafting which can occur naturally or with human (or elf) intervention.
Effectively combine these two real-world things;
The roots of large trees packed closely together will become grafted: https://academic.oup.com/treephys/article/31/6/575/1657428/Why-should-trees-have-natural-root-grafts
And a specific example of a massive colony organism joined at the roots; https://en.wikipedia.org/wiki/Armillaria
They cultivate fruits, nuts, and berries by forced growth in easy to access hidden areas in their city. They could also eat mites, fungus, decaying or damaged plant parts in a symbiotic way that benefits the plants in which they live. They have water running through pseudo-natural aqueducts (crafted by woodwork or singing, writer's choice) for both consumption and aggregation, that can be controlled entirely with gravity and simple plumbing. This could also take care of the waste problem, but why not recycle any waste? Decommission parts of the city when they have outlived their usefulness. Those decommissioned areas are used as landfill in a way that would be beneficial to their woodland home.
The elves need never even see daylight. They would only risk exposure if they venture above ground for whatever uncommon reason, or if a human manages to do the reverse; but they could, barring the need for air/light/water holes, be entirely closed off, or as closed off as you feel justifies their non-interaction with humans.
Thinking about unmentioned City problems:
This solution already solves the unmentioned problem of housing vs population growth to the extent of the available forestable area, provided that they are able to expand the forest through their magical singing or stem population growth enough that the forest consistently outgrows the population (maybe easier said than done).
There's the problem of fires... A very serious problem that the elves could have little control over, or perhaps they can use their abilities and waterways to topple trees and create firebreaks and controlled flooding?
There's competing growth (the obvious one). Humans etc trying to expand into forests or just felling trees as a source of wood. This would be manageable with counter growth in other directions only depending on the scale of the human activities.
There are a whole host of other problems that a city faces such as crime, government, etc. but nothing I can think of that would need to be handled particularly differently in this scenario vs a typical, real-world (simpler times) human city.
They live on top of the canopy of the forest and therefore would not be visible from below. A person wandering in the area would not realize he's walking below an elven city. Looking up will only allow a glimpse of the thick canopy. Deeper to the center of the forest it will be too dark for a commoner to explore.
It is fairly visible when observed from atop of mountains, but this is solved by avoiding settling near mountains.
Note that the question does not require to hide the fact that elves live there. People might know the forest is where elves live and even have diplomatic relation, but they do not know exactly where the city is.
As the elves can mould the trees, they could use them for water supply. They can alter some trees to obtain water from the soil using the roots, and then liberate in the surface as (a kind of) sap. The food could be obtained through foraging and some hunting and fishing in the forest, they could breed game for feeding and defense (deer rider elves for example).
Made properly, all the organical trash could be composted (again, using moulded trees as familiar compost deposit), the broken pieces of pottery (if they use, but I would favour the wood and hide recipients) could be grounded and used as construction material for some structures (roads inside the city, brick and mortar structures, and so), the metal could be melted and used again...
How to hide the city? Well, you could make it inaccessible with camouflage and abrupt terrain, (maybe a forest in the top of a mesa in the middle of the forest?) if you rounded it up with bushes and very thick foliage (like Fangorn forest in LotR) this could be a first line of defense. The second one should be the mesa itself (or something like Gondolin from the Silmarillion). You can take in consideration that you can mould the roots to make room for passages under the ground, so they could live in the top of trees and use the inside of the tree to go underground using these paths carved by the roots.
If they can control plant growth, an impenetrable thicket such that a traveller would go round it, and round a bit more for the next thicket and so on would be quite a deterrent, as well as camouflage. This would combine well with flooded forest ideas. The outermost trees should be too small to be desirable as firewood/construction timber for the neighbours. Too twisted for timber may also help.
By enhancing plant growth in nearby regions of the forest (tall, straight, fast-growing trees, plentiful fruit on easy terrain), other people wouldn't want to use the forest-city for its resources.
I don't think you can hide.
Temperate climate: Among others, you need warmed dwellings and places to grow and store food. This will mean cultivated grounds. Not to mention the strange trees you have growing. There is no way someone wandering in the forest will mistake cultivated fields.
Tropical climate: will make your food source and living a lot easier, as you can dwell in the trees for both.
But once you start domesticating ground-dwelling creatures, like horses and sheep. Those flocks will really stand out. And we are not talking about bakeries, mills or smithies. Those need a solid footing. And fireproof.
The Five Senses
Every large group of creatures, humans, sheep or even wildebeests, will make itself noticed. For creatures that hunt, it will be impossible to miss. Not just for humans.
Sight: if not the itself group is noticed, then their sleeping quarters will be different from the surroundings. Unless extremely light footed, every living thing leaves a trace. Don't forget, humans can be extremely good trackers. It is very hard to remove all traces of habitation.
Smell and Taste: Food, cooking and the end product of all that will smell. Even with sewers and very good waste management systems you will be able to tell the difference between a forest and a settlement. Cities just smell different from the normal forests.
Sound: With 10K+ sentient being living together you have culture. There is talking, shouting, whispering and singing. Our modern air warning systems don't reach everyone, so I don't think you can even have them all silent when some one strange is near. Never mind kids and babies. Good luck with pets and domesticated animals.
Touch: If trees grow faster with their singing, there is a good change their structure will be different. Maybe the trees will have a different touch to them.
To hide in plain sight
What we have discussed up to this point is the normal observation of an intruder. We can play with that. But there are more options. I will list some from (mostly) harmless to lethal.
Drug every intruder by some kind of psycho active substance. Magic Mist? Let them hallucinate. Make them forget. Give them a very bad trip. Make sure they get back to tell the story. What ever they see, nobody will believe them. And few will try to do the same.
Enslave every lost human. Make them blind. What you can't see you can't tell. Very hard to get back without sight. Use them (up) with hard labour you don't want to do yourself. Even if they escape, oh the horror stories they can tell.
All these options share one thing: stray into our forest, it will go bad for you. You know something bad is there. An unknown horror is a bigger horror than a known one. Become the bogey man. Become the thing that lurks in the shadows. Become the thing they fear.
*Note: once there are electric lights, binoculars, air balloons or airplanes, your game is up. They know you are there. If you still want to be left alone: aggression.
Solve the food problems with magic. Since they can grow plants faster and bend them to their will, there could be elven magic farms bringing in crop every week, making a small space enough to feed a lot of elves.
They should be coating their wood with fireproof magic.
Place the city inside a huge forest, create a huge maze with a lot of dead ends around it and let the elves use the dead ends to get inside. (E.g. caverns, dead trees and holes in the earth connected with a tunneling system.)
Let them create their storage units all underground so that the city gets smaller.
Elves are nature bound so I would imagine that most of their waste is organic. This can be easily turned to new earth by magic farmers. Excess earth can be used to fortify the outer wall.
Water transportation could be done by roots. They create clothes out of hemp they speed-farm if needed.
If the city is connected somehow to a mountain, this is where they could get metals from.
The elven city can be a lot smaller than human cities. In war, for example, humans need maybe a sword a month for each soldier. Elves use all their life the same magic sword, so there is simply no need for big production facilities.
Assuming the person is simply wandering through the area and not searching for the elves the answer is simple: people don't look up. Position yourself above a crowd of people walking past and you'll rapidly notice that almost no-one looks up. This is likely to be even more true in a forest where they will need to pay attention to footing and undergrowth.
All you need to do then is position the elven city high up in the trees.
If elves like space, with wide airy dwellings, they are likely to be well spaced out and the low population density will help hide them, and keep the impact of their scat undetectable as well as dilute the impact of their farming practices. Manipulating plants means that they will grow their food at height in the trees, mostly from fruit, and supplement it with a little hunting for birds or arboreal mammals. Their excellent night sight means they light no telltale fires at night, while the noises of the forest and the dense canopy both helps hide them from view when the rare individual looks up and muffles and hides the noise they do make. Water can be collected from rainwater.
Quite easily. After all, there are still species of animals and plants only being discovered now in the Amazon - they have no magic ability either and people were actively looking.
Simply have the city in a harder to reach, dense rain forest area. Clean water isn't an issue, the tree canopy can be "bent" to cover the clearings (for farming), have the areas around even denser (and away from obvious "human" transportation such as navigable rivers). Waste is like any modern-day issue, bury it or recycle it! Rain forests are huge and contain just as much above ground as below it (there are miles of caverns and underground grottos).
Lots of smaller enclaves would be easier to hide than one HUGE enclave (in a rain forest environment for example) as even overflights are likely to ignore the odd bent tree area but will certainly notice a HUGE gathering of odd-looking trees.
The Anasazi, in the United States (Utah in particular) were known to have lived in cities hid by caves. And depending on how well you want your city hidden it would work for you too. The issues here would be the same they faced, water, cultivation of crops and room to expand over time. This was done in our world, without magic, so depending on your world this could be a possible solution or an excellent means of using natural terrain to be improved via magic.
If, as you say, you are going Tolkienesque then he already did this. You simply enchant the trees to open or close paths so as to divert the traveler away from or around the city.
If the trees can't move then the elves can prepare and maintain well-made pathways for the locals to follow and camouflage the entrances to their realm.