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In my world there's a salt flat like Salar de Uyuni in Bolivia (of different size if need be)

enter image description here (source)

Is there a chance a medium- to large-sized forest could have grown naturally in the immediate vicinance of the salt flat?

What changes to the biome (or to the trees) would be needed, otherwise?

Note: the surrounding area does not have to be like Bolivia, in can be a salt flat in any climate.

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    $\begingroup$ @L.Dutch Well, I'm building a world which is not Earth and asking if I need to change any general "rules" in my world to allow for a forest to grow naturally in the vicinity of a salt flat. I feel like there are a lot of similar questions here which have not been flagged as off topic $\endgroup$ – Hankrecords Jan 26 '18 at 10:51
  • $\begingroup$ If it is a separate planet, then there could be plants that evolved in that environment. Many plants on earth are tolerant to salt, fe. mangroves create whole forests along the shore line. $\endgroup$ – Nuloen The Seeker Jan 26 '18 at 12:57
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The 'forest' is a forest of cacti

enter image description here

I searched 'salar de uyuni forest,' and this is what popped up. There are islands in the middle of the salt flat that have cactus growing on them.

It wouldn't be too much of a stretch to make your cactus forest bigger and more dense. If the islands have fertile soil, then a dry forest can get pretty dense; and pretty green after the rainy season. Here is a spiny forest from Madagascar after the rainy season. The rainy season is about the same length and wetness in Madagascar as it is in Bolivia.

enter image description here

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  • $\begingroup$ Here's what's bugging me though: would rain "hamper" a salt flat or would it stay the same even after a rainy season? (interesting idea to bring cacti into the equation, though) $\endgroup$ – Hankrecords Jan 26 '18 at 14:05
  • $\begingroup$ Ok, apparently there are rivers which overflow into the Salar de Uyuni during wet seasons, so it is possible indeed $\endgroup$ – Hankrecords Jan 26 '18 at 14:09
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    $\begingroup$ @Mołot Yeah, I guessed as much. I was in doubt whether it would have reduced the "saltiness" in the area. Since that is not the case, floods are actually perfect for my setting :) $\endgroup$ – Hankrecords Jan 26 '18 at 15:30
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    $\begingroup$ @Hankrecords so long as the water doesn't have anywhere to go from the salt flats, and has to evaporate out, it should remain nicely flat. Bonus if you have a neighboring mountainous region that is known for rich surface and near-surface salt deposits, which can help replenish the flats -- rain carries salt off the mountains (eroding them in the process), and then the runoff has nowhere to go, so the water eventually evaporates, leaving behind the salt flats. $\endgroup$ – Doktor J Jan 26 '18 at 18:49
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    $\begingroup$ @Hankrecords going this route, you could even have skeletons embedded in the salt from creatures that wandered across and died on the salt flats. If the waters aren't too rough, over the course of several subsequent decades salt carried down from the mountains would accumulate on the flats (making them "deeper", and assuming the water flow is gentle enough to not disturb the skeleton, the salt layers built by these cycles would begin building up around it, eventually burying it. $\endgroup$ – Doktor J Jan 26 '18 at 18:51
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Highlands and lowlands. Salt flats are dried up bodies of water. That means that they are low lying, which is how they filled with water in the first place. Adjacent to low lying areas are sometimes higher areas. These areas have a different climate than the low lying body of water / salt lake / salt pan.

Here is an example from google satellite image..

Bonneville salt flats Depicted: the Bonneville Salt Flats. I zoomed out to include part of the Great Salt Lake and Salt Lake City to help orient. But at 7 o'clock from the Salt Flats are the Ipabah Peaks.

Ipabah peak http://www.peakbagging.com/UTPhotos/Ibapah.html

It is a forest. Other higher elevations in the vicinity of the salt pan and salt lake are also forested.

The key to different biomes in close proximity to one another is change in elevation.

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    $\begingroup$ Or a bit further west, you could look at the Truckee River, which (prior to the early 19th century Newlands Project) drained into Pyramid & Winnemucca Lakes, with the Smoke Creek and Black Rock deserts to the north. The mountains generally have rather sparse forests of conifers, with cottonwoods along the river & aspen groves around mountain springs. $\endgroup$ – jamesqf Jan 26 '18 at 23:05
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Yes, many plants have evolved to cope with salt, some filter it out at the roots, others absorb it , put it in the leaves and then shed the leaves. Mangroves have evolved several ways.

Coconut trees grow right next to the sea, ideally they actually overhang the water. They separate out the salts and store them in various parts of the plant.

Basically anywhere there is water, plant life will evolve to cope with whatever else is in the environment eventually and thrive.

Ground water with an impermeable layer of rock between it and the salt pan area would do it or something similar. No need for humidity. We have several villages here which have fresh water springs within metres of the sea and no salt in them at all due to the rock.

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    $\begingroup$ Also some kind of cabbage grows well in salty terrains (ask the Dutch). Now, a forest of coconuts and cabbages is really interesting $\endgroup$ – L.Dutch Jan 26 '18 at 11:53
  • $\begingroup$ @L.Dutch a bit of a monotonous diet, but you could live on it I would think. $\endgroup$ – Kilisi Jan 26 '18 at 12:12
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    $\begingroup$ Thanks for the insight on the salt-resistant plants! One issue remains, however: AFAIK, salt flats only form where the rate of evaporation exceeds the rate of precipitation, but in order to have a forest of mangroves/coconut trees (or even cabbages) I would need a humid area. Is there a way an arid enough area for a salt pan to form could be right next to a humid enough area to sustain a forest? $\endgroup$ – Hankrecords Jan 26 '18 at 13:19
  • $\begingroup$ Yep, make it up, ground water with an impermeable layer of rock between it and the salt pan area would do it or something similar. No need for humidity. If there is water you can have plants... whatever else (within reason) is in the environment the plants will evolve to handle. $\endgroup$ – Kilisi Jan 26 '18 at 14:53
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    $\begingroup$ @Abigail you don't even need precipitation, springs would do it. The problem with precipitation is that it may well turn your salt flat into brine if you had enough to keep a forest going next door. So ground water would be better. I'll add some reasoning to my answer. $\endgroup$ – Kilisi Jan 27 '18 at 2:48
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The other option, apart from salt tolerant plants, is to have a rain effect zone; an area of high rainfall at one margin of the salt-flat, while most of the salt-flat is in a rain shadow, will have much lower salinity. High water inputs cause salt to migrate down into the subsoil instead of it sitting on the surface. This means that part of the old lake or seabed could be in salt-flats while other areas are in grassland or even forests.

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  • $\begingroup$ From what I have understood reading the wikipedia article, in order for a rain shadow to form there needs to be an obstacle for wet clouds, and this would mean having a mountain between the salt flats and the forest, which is not what I'd like. Are there any other ways a rain shadow could form? $\endgroup$ – Hankrecords Jan 26 '18 at 13:15
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    $\begingroup$ @Hankrecords the salt flat may be in a valley. The forrest would then grow at the valley's borders. $\endgroup$ – Renan Jan 26 '18 at 13:25
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    $\begingroup$ @Hankrecords You can add a few through-mountain channels that end up as fresh water wells in the shadow side of the mountain. $\endgroup$ – ratchet freak Jan 26 '18 at 13:25
  • $\begingroup$ There are two ways to get low rainfall, sorry I forgot that article only deals with orographic rainshadow. Where the prevailing winds bring in dry cold air and no real moisture, like on the pacific coast of Peru, the areas where the air stays dry most or all of the year receive little or no rain while areas that are close by and get warm moist air can experience extremely high rainfall. A salt flat in the right setting could have a similar experience. $\endgroup$ – Ash Jan 26 '18 at 13:30
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    $\begingroup$ You wouldn't need the mountains between, mountains along part of the edge to trap rain clouds in one part of the basin while they pass over the rest would work. $\endgroup$ – Ash Jan 26 '18 at 13:39
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There is no need to change anything for a dryland forest to grow near a salt flat, other than a change in altitude of perhaps only several metres and the right level of natural rainfall (not too much). A salt flat can be maintained by groundwater largely independently of local rainfall if it is not a dry salt bed.

Have a look around Sea Lake (Lake Tyrrel) in Victoria, Australia and you will find that there was originally much forest that has now been cleared for farming. The salt lake there is in a depression.

Lake Tyrrell is a shallow, salt-crusted depression located in the Mallee district of north-west Victoria, in Australia. Wikipedia

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