tl;dr: what issues would cause more risk than reward for a civilization to settle a fertile, heavily forested area; bonus points for less magic / historical examples / it being a threat

My son, venture far beyond the Seas of Steel,
and pacify the steppe, summit the mountains.
But journey not into the Dark Forests...
There is nothing to be gained there.
            - Mother to Son


In my world, the main empire I'm focusing on (of late Classical to Early Dark Ages technology level) has begun expanding on a continent the size of Eurasia. Explorers cross a large mountain range, and discover a large area of forest.

However, even a few hundred years after the discovery of this land, no significan t attempts have been made to settle the forest. It is only settled along its coastline, as well as a single, heavily guarded road area through its interior. What kinds of unique dangers would prevent such a civilization from developing the land in the forest?

Some further details about this culture:

  • They've had no trouble settling other areas, mainly along coastlines but also in steppe or even desert biomes. They've even settled a different (smaller) forest.
  • As of right now, they don't necessarily need more resources to sustain themselves, but having more materials for trade is always good.
  • The world that they "exist" on is being simulated by a massive supercomputer for scientific purposes, and because of that...
  • Magic exists, in the form of some individuals in the computer using bugs in the code to escalate privileges to be able to modify environmental variables (the random number generator being the only known bug right now). This results in some individuals being able to modify the chances of certain events succeeding.
  • The current forest is inhabited by hunter-gatherers, much like the current Amazon.

I'm specifically looking for a real-world reason (bonus points for a specific danger) that would cause more risk than reward for a civilization of significant resources in settling a heavily forested region. Magic can be involved, but I'd rather the solution not rely solely on magic.

(This is my first question in a long time, please remind me of any issues with the question [topicality, duplicate, tags, specific details, etc.] as well as ways to improve them. Thanks!)

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    $\begingroup$ The Everglades are fertile and heavily forested, but nobody wants to farm there: It's hot, swampy, and full of voracious alligators. Much of Alaska and Northern Canada is fertile and heavily forested, but nobody wants to farm there: It's cold and full of voracious mosquitoes. $\endgroup$
    – user535733
    Commented Dec 25, 2019 at 8:05
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    $\begingroup$ Actual historical European medieval states had land aplenty; what they did not have was workforce. They did not need any more land, they needed people. Since they had more land than people at home, they had no incentive whatsoever to go out and colonize foreign lands. Look at the history of the Crusader States: they never got enough colonists to become sustainable -- and the Crusader States were not all that far from Europe. Or look at the history of colonization in the Americas; it did not get any traction before the 17th century, and accelerated only in the 18th century. $\endgroup$
    – AlexP
    Commented Dec 25, 2019 at 13:19
  • $\begingroup$ @AlexP - I would love to see that comment fleshed out into an answer, with more sentences dedicated to each of your examples, $\endgroup$
    – Willk
    Commented Dec 25, 2019 at 13:55
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    $\begingroup$ Does “less magic” preclude superstition? i.e. thinking there’s magic? $\endgroup$
    – WGroleau
    Commented Dec 25, 2019 at 20:57
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    $\begingroup$ @WGroleau shouldn't preclude superstition. I just didn't want it to all be handwavy öh yes because magic $\endgroup$ Commented Dec 26, 2019 at 17:19

13 Answers 13


In the real Middle Ages

  • "In my world, the main empire I'm focusing on (of late Classical to Early Dark Ages technology level) has begun expanding on a continent the size of Eurasia. Explorers cross a large mountain range, and discover a large area of forest."

    Great! We have a nice historical example. The time is the 11th century. The "great empire" is the Kingdom of Hungary, the "large mountain range" is the Southern and Eastern Carpatians, and the "large area of forest" is, well, most of territory which would eventually become Wallachia and Moldavia.

    The only difference is that there were no "explorers", because they were not needed. The geography of the land was very well known, and had been known for a very long time.

    So what happened in the real history?

    In the 11th century, nothing. The kingdom of Hungary sat on their side of the Carpathians.

    In the 12th century, nothing. The kingdom of Hungary sat on their side of the Carpathians.

    In the 13th century, nothing. The kingdom of Hungary sat on their side of the Carpathians.

    In the 14th century they attempted to establish suzerainty over Wallachia; mind you, not to conquer, just to establish suzerainty. By that time it was way too late; Wallachia had become an organized state, and Basarab I of Wallachia defeated the expedition of Charles Robert of Hungary.

Why was it like this? Why didn't Hungary expand into the power vacuum to the south and east? And this is not the only example in European history; remember, for example, that the entire (densely forested) region south and east of the Baltic was only conquered (by the Teutonic Knights) in the 13th century; before that, the Baltic people were left alone to fend for themselves.

There are two fundamental problems with envisioning western European medieval "empires" (note the scare quotes) hell-bent on territorial expansion:

  • First, the perennial problem of western European medieval states was lack of people. There was a severe post-classical population crash in Europe; it took Europe one thousand years to recover the population level it had in the 2nd century, which was not very high to begin with. Land they had aplenty. Forest they had aplenty, and they were actually offering incentives to people to clear it. There was forested and uncultivated land in England, in France, even in Germany, not to mention the large truly wild areas of Scandinavia, of Poland, of the Baltics, of Ukraine, and of western Russia. Western Europe had more than enough land for its people at home, they did not need more land.

  • Second, there was no way to trade extensively overland; they simply did not have the transportation technology. A mountain range was a very effective barrier to trade. Oh, they could trade luxury goods, small enough and expensive enough; but bulk goods? Timber, grain, wine? Not overland, they couldn't.

Remember the exalting and sad story of the Crusader States: established in a glorious war of conquest in the late 11th and early 12th century, and lost in the late 13th century. The Kingdom of Jerusalem, the Principality of Antioch? They never managed to bring in enough colonists to become sustainable; they never reached a population level sufficient to defend themselves against the Saracens. And why was that? Because Europe itself did not have enough people; sending masses of colonists overseas was out of the question.

In conclusion, it is not at all surprising for a western European kingdom to just sit on its side of a moutain range, beyond which is a dense forest inhabited by dirt poor people. It is to be expected.

If you want the "great empire" to seek to conquer the forest land you must give them a strong incentive; I suggest that instead of "hunter-gatherers" you make it inhabited by a splendiferous civilization, swimming in gold and silver. Then the empire would be interested. But poor peasants they already had; land they already had; forest they already had: they had no reason to embark in costly attempts at conquest and colonization.

General considerations

The question states that this "medieval" "great empire" is actually in another world. The issue is then, what makes this "great empire" medieval?

The western European medieval society was a historical phenomenon very highly specific to western Europe. It is extremely unlikely to get anything quite like it in another world.

Think about it.

The western European medieval society is a historical aberration. A highly advanced, highly literate, fully functional civilization collapses due to basically a long streak of historical bad luck. To bring about the western European Middle Ages, you need: the Crisis of the Third Century, during which a previously functional empire finds itself mired in a century of civil war; plus a few centuries of barbarian invasions; plus a devastating plague; plus the emergence of Islam bringing the collapse of the (Eastern) Roman Empire.

There were feudal societies elsewhere, in Persia, in the Ottoman Empire, in India, in China, in Japan, and those lands had their own medieval periods; but the western European medieval society, with its highly elaborated double hierarchical system, secular and spiritual, was one of a kind.

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    $\begingroup$ Medieval civilisations were plenty advanced and literal too; but the population loss was unbearable. If our modern civilisation lost 95% of the people over a century, it wouldn't matter how advanced or literate we are - we'd be stuck for centuries, recovering. $\endgroup$
    – Luaan
    Commented Dec 25, 2019 at 18:25
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    $\begingroup$ Dunno about Moldavia, but "the Baltic people were left alone to fend for themselves" is simply not true. These tribes not only resisted conquest, the threat posed by them was actually the reason why Konrad I of Masovia invited Teutonic Order to deal with them (what later backfired, but that's another story). en.wikipedia.org/wiki/Old_Prussians $\endgroup$
    – Ijon
    Commented Dec 25, 2019 at 22:44
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    $\begingroup$ I am not a historian, but to me it seems that the perceived "vacuum" in Pagan areas of Europe is a result of a bias, Pagans simply haven't left written records and their languages and culture were actively eradicated $\endgroup$
    – Ijon
    Commented Dec 25, 2019 at 22:49
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    $\begingroup$ I don't buy the explanation, but the example is still a fact so it stands. en.wikipedia.org/wiki/First_Crusade#Situation_in_Europe says that the crusades were specifically started to "cleanse" Europe from excess, useless people (primarily among nobility since those were doing the most harm but anyone could participate). I guess they were directed at Palestine rather than e.g. Eastern Europe solely because the former was seen as a higher reward/risk ratio. $\endgroup$ Commented Dec 26, 2019 at 14:41
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    $\begingroup$ @Peteris I think we actually agree here - conquest may be unprofitable because of hostile locals, sure! The original question, and the context of AlexP's answer, assumes that there is (nearly) nobody to oppose invasion, and I just wanted to point out that at least in case of Prussia there was, in fact, somebody who was not only able to resist for significant time, but even to be a threat for nearby "civilized" kingdom. And that's why I consider Prussia to be a rather poor real-life match for a situation described by OP $\endgroup$
    – Ijon
    Commented Dec 27, 2019 at 17:07


In reality, mosquitoes have prevented humans from developing rain forests. A forest filled with aggressive insects can be pretty effective at keeping people out.

I first heard about the benefits of mosquitoes in protecting natural habitat from a podcast, but I can't remember which one. Maybe radiolab or freakonomics.


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    $\begingroup$ Not just mosquitoes, but mosquitoes carrying diseases. Yellow fever kept a lot of the tropics undeveloped for a long time. $\endgroup$
    – arp
    Commented Dec 25, 2019 at 8:56
  • $\begingroup$ There was the claim that mosquitoes (the diseases they carry, naturally) are responsible for something like half the humans that ever died on this planet. No idea how close that is to the truth, but it doesn't sound too far fetched given that humans have spent most of their prehistory in areas full of deadly diseases carried by mosquitoes. $\endgroup$
    – Luaan
    Commented Dec 25, 2019 at 18:09
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    $\begingroup$ This reason was enough for europeans to not wander too deep into Africa until XIX century when medicine was advanced enough. $\endgroup$
    – user28434
    Commented Dec 26, 2019 at 12:26
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    $\begingroup$ Mosquitoes provide protection from podcasts? Who knew? (Yes, I know that's not what you meant...) $\endgroup$
    – EvilSnack
    Commented Dec 26, 2019 at 16:05
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    $\begingroup$ In Sub-Saharan Africa, mosquitoes carried malaria (among other diseases). This disease so adversely affected Europeans that it incentivized them to enslave Africans who were resistant to the parasites. Having one copy of the resistant gene let you survive, having 2 copies resulted in sickle cell disease. $\endgroup$
    – Tangurena
    Commented Dec 26, 2019 at 16:07
  1. Cutting big old trees down is hard, dangerous work.
  2. They don't have the population density to need the land.

These two are likely to be the reasons ancient forests survive into the modern age, but there are more specific reasons you could choose.

  1. The settlers are sailors and fishermen, moving into the interior holds no appeal to them. They're coastal people, not farmers.
  2. There's a mountain range in the way. That's not a trivial obstacle.

and that's before you get into the more traditional

  1. The natives are hostile, but mostly keep to the forest.
  2. Bears. There could be worse than bears, including wild boar, big cats, wolves etc. Large wild animals prior to firearms are considerably more dangerous than we now consider them.
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    $\begingroup$ Hm, not just sailors even - human populations have stuck to coasts and rivers for quite long; waterways were the only practical way of transporting goods before the railroad came around. Europe happens to have a dense network of navigable rivers (that have been further developed by the settlers). A mountain range and no decent river network, and settling the area becomes very difficult. $\endgroup$
    – Luaan
    Commented Dec 25, 2019 at 18:15
  • $\begingroup$ Thanks for the ideas! $\endgroup$ Commented Dec 25, 2019 at 19:08
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    $\begingroup$ "'1 + 2' - hard, dangerous, work + needs high population" - This is only true if you want to harvest the wood quickly, e.g. to sell the lumber. Clearing large swaths of forest is as simple as peeling strips of bark off a tree, in a ring around the trunk. Then waiting a few years. This method, called girdling, can easily clear a substantial area, with just a single person. Even a young son can be assigned to the duty, as some colonial american farmers did. People have been aware of this method - and used it to clear forested land - for millennia. $\endgroup$
    – Jamin Grey
    Commented Dec 26, 2019 at 19:31
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    $\begingroup$ 3+4 works very well, as Luaan mentions. A mountain range would split the drainage basin in two separate directions, almost ensuring there would be no rivers crossing it, forming river "highways" for trade and travel. 6 - bears and wild boar somewhat work, but moose are far more dangerous and should be added to the list. All three of those never stopped humans from settling an area before though, are edible, and can be systematically hunted down by humans working together - they are far more dangerous to individuals or pairs travelling alone. Overall, I think 5 makes the most sense. $\endgroup$
    – Jamin Grey
    Commented Dec 26, 2019 at 19:36

The mountain range is in the way.

As a gross oversimplification, there are two possible patterns of settlement:

  • Develop a piece of unsettled land next to the settled lands. That means the geography will be known, same for wild plants and possible crops, if your plow breaks it will be a relatively short hike to the next blacksmith, but on the other side of the coin there may be a lord who believes that he is due taxes from you.
  • Develop a piece of land far away from from any baron or mayor. Grab your sturdy axe, a bag of seed corn, another bag to last to the next harvest, and go into the unknown. If your axe wears down before the fields are cleared, or if the rats get into your corn, or if a cougar finds you tasty, you might be able to stagger back into civilization, haggard and broke.

The mixed bag would be to to travel with a group into distant fields. The best of both worlds, or the worst of both worlds?

Assume that any significant, successful effort goes the first way. Yes, there are a few lone prospectors and trappers in the jungle. But they failed to leave their mark. Huts here and there, some abandoned, some inhabited, some with the grisly remains of a body.


Your magic system isn’t magic: It is based on luck.
Those few that can influence the random-number generator are always extremely lucky. That is what gives them the edge in life.

However, that random-number generator is flawed in more ways than one. The location on the planet is part of the seed of the generator and this leads to some areas (like your forest) where luck comes out really badly: bad luck all the time for everybody.

That's what makes that forest so dangerous.
Hunting is difficult because the luck affects the behavior of the animals. Wild animals that usually avoid humans will have a very high chance of attacking humans instead. The chances of mistaking a poisonous plant or mushroom for an edible one are very high. Only the best, most skilled hunters-gatherers can survive there, since their skill takes the luck factor out of the equation.

Traveling through the forest is possible but takes a lot of precautions, because you need a lot of redundancy in food, supplies and gear. With the bad luck to be expected, food goes bad, gear breaks, etc.

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    $\begingroup$ Wow this is actually a great idea! I think I'll probably include this in my writing thank you :) $\endgroup$ Commented Dec 25, 2019 at 19:09
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    $\begingroup$ @JSCodersaysReinstateMonica You're welcome. As a programmer that has worked on random-numbers generators this immediately came to mind :-) $\endgroup$
    – Tonny
    Commented Dec 26, 2019 at 15:27

Logistics. At this technological level the main means to move bulk materials is ships. Rome was supplied by grain from Egypt by ships, for example. Small-time substinence farmers may settle by foot or by ox, but they cannot trade whatever they grow (unless they choose to become ranchers, a la Wild West). Come up with some explanation why ranching is impossible - no animals domesticated, or the forests are full of predators, or some infection of the animals (tsetse-born-like).

If there is no means for trade, no wonder nobody wants to settle there (except for outlaws, I guess).

  • $\begingroup$ Logistics was my thought too. Crossing those mountains and clearing that forest sufficient to settle the land requires lots of logistical support. Even more so if the settlers remain part of the parent empire. $\endgroup$ Commented Dec 26, 2019 at 17:05
  • $\begingroup$ "At this technological level the main means to move bulk materials is ships." This was so true that it's left its mark on the language. Even today, when we've had railroads for centuries and semi trucks almost as long, moving material in bulk is still called "shipping." $\endgroup$ Commented Dec 26, 2019 at 18:43

Cribbing from an M. Night Shyamalan movie, have the trees or some ubiquitous plant in the forest release a chemical that produces anxiety, so that anyone who tries to venture in — much less clear a patch of land — will increasingly be filled with terror. Indigenous people would have developed an adaptation so they aren't affected; perhaps they've discovered an herb that can be used as an antidote, or a way of concentrating the chemical to use as a fear-weapon. At any rate, that would explain both why the forest hasn't been settled and why the road is heavily guarded. Even passing down the road would fill travelers with an overwhelming sense of dread.


Once dry, the logged tree wood is highly explosive, propelling the seeds of the trees in all directions, when ignited. Treeseeds will sprout in travellers and animals they penetrated alike.

Luckless travelers can be found "grown into the trees" theire faces still screaming.

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    $\begingroup$ Very imaginative. I like it :) but most likely I'm not going to use it in my world. $\endgroup$ Commented Dec 26, 2019 at 21:33

If your medieval society has a system of land ownership that resembles those of historical western Europe, then you can fall back on a political/legal/sociological reason: all undeveloped land belongs to the monarch, and he or she does not choose to make that land available for development. The monarch could be holding the land in reserve to have it available to enfeoff new followers; the monarch could also judge that allowing the land to be developed would upset the current balance of economic and political power; the monarch could want the land available for the crown's own use; etc.

You could even have the land patrolled by "gamekeepers" who make sure that no one is poaching on the monarch's land, on pain of death.

  • $\begingroup$ Interesting political reasons, I like this too $\endgroup$ Commented Dec 26, 2019 at 21:34
  • $\begingroup$ He is, however, unlikely to have the manpower to enforce it. that was a chronic problem. $\endgroup$
    – Mary
    Commented Mar 3, 2021 at 23:44

There does not have to be a complicated reason ... a bit of reading on Roman history might do.

  • Your Smaller forest approximates Gaul (france)
  • Big forest over mountains (instead of Rhine/danube) approximates roman Germania (germany and east europe)

A strong/ centralised government meant a few big battles replaced the Gaul government (and tax collection) with Roman under Julius Caesar.

fewer obviously resources and chaotic government meant "germania" was never worth anything except as a place to capture slaves / prove your battlefield rep and the chaos meant peaceful encroachment wouldn't happen.

Romans could get new land to develop a lot easier almost anywhere else in the empire and without a solid reason to do it, sounds like the same applies to your empire.

For contrast read a bit about the US history until the mexican-american war ... population pressure and resource demand meant any danger would be faced

  • $\begingroup$ welcome to Worldbuilding.SE! Excellent analogue from history, I'll research Rome a little more. I hope you enjoy your stay! $\endgroup$ Commented Dec 26, 2019 at 21:35

It could be as simple as the forest is inhabited by a people who do not want to be disturbed/don't take kindly to strangers, and are not shy about driving people off. Since there isn't a huge driving force sending people into this region, those who do end up going there will be few, and likely solitary. Not good odds when going up against people who know the area, and who are well supplied and have the extra incentive of defending their home. People who don't have a need/desire to go to this place specifically for some kind of benefit (a trade good, shortcut, etc) may also just choose to explore elsewhere for logistical reasons.

Since the area is somewhat geographically isolated the animals may be somewhat different - larger, smaller, both of which could pose an increased threat, especially if you've not expecting it. Plant life being different could make finding food very difficult, especially if toxic species are endemic or difficult to identify. Insects (ranging from poisonous to merely annoying) would also be deterrents. Is there water available in the forest, and is it drinkable for humans, or does it require filtration? That puts a very tight timeline for any exploration if you're not able to get sufficient water.

It may be very difficult to find your way through the forest. If it's especially thick or fast-growing trails may become overgrown as quickly as they're cut, and any locals will likely encourage this to keep outsiders out and make wayfinding even more difficult. If your culture depends on the stars or visual cues to navigate an inability to see them will also make navigation and orienteering very difficult. If the road had a high cost (lives, money, resources, etc), others may discourage people who might want to go further into the forest from doing so as it's so dangerous.

When it comes to building structures or developing the land otherwise it may just not be good land for farming - soil not the correct pH for the crops they'd want to grow, wood not what they'd want for their needs, lack of stone for building if that's what the culture usually builds their structures from, or the effort required to make it useful may just be way out of proportion to the expected benefits.

Getting lost in a huge forest, with no guarantee of being able to find food or water, hostile locals, animals that may want to eat you, and no particular benefit to this adventure? You'll get some people who want to go ahead for the adventure and bragging rights sure, but enough to make major inroads in exploration? Doubtful. I don't think magic as people in this setting have access to it would be able to solve all those problems to a sufficient degree that exploration would have an acceptable level of risk for most people.


Since “magic” is taking advantage of bugs in a simulation, perhaps the taboo could be superstition arising from another bug that manifested in the past.

Or, since the whole thing is a simulation, perhaps the taboo is itself a bug in the program.


The Greek Way

(source: ecosia.org)

A real world example would be that the Greeks did not colonise Ukraine or the interior of any land for that matter. Greek colonisation might be a great starting point for your worlds colonisation for this reason. The Greeks did not conquer great stretches of land, they established Cities along the coast. Why? Because they lacked the people to create large land empires. And because the costal cities had access to the sea, which meant that they could remain connected to the rest of the world.

Just look around the map many regions with attractive interiors were ignored. Even one very fertile and heavy wooded area filled with barbarians: Ukraine. The Ukraine would later be called the breadbasket of Europe. However Crimea and Sicily came to fill this role for the Greeks.

So why is this area not of interest?

  • Your people establish costal towns, not inland colonies. At least not unless they would be very useful.

  • Other regions, which were colonised earlier, already satisfy the markets for crops and wood.

If you would like to learn more about Greek colonisation, I'd recommend this video as a starting point.


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