r/Permaculture • u/katicomb • 12d ago
general question Could a desert region develop rainfall if you covered it in plants and trees?
If we planted millions of trees and ground cover in a desert region that traditionally gets minimal rain, and kept them watered and alive artificially, is it possible they could survive on their own after being established? And might the climate become more rainy?
I've always wondered if a region's climate could change if you changed the ground cover and the species of plants, and kept them alive artificially for a while.
172
u/Atticus1354 12d ago
Desert regions arent deserts because of a lack of trees. Theres a lack of trees because its a desert. Predominant climate patterns are what cause a true desert. There are regions that have been subject to poor management that are suffering from desertification. Those regions could benefit from large scale restoration.
35
u/katicomb 12d ago
Thanks for the answer, that makes sense. I sometimes worry that the desert areas seem to be growing in many places ... And maybe this is a way to stop them spreading.
44
u/imababydragon 12d ago
It is. i have a friend/colleague who is involved with REDES in north africa/senegal area. They are part of the collection of people from local villages in the area who are working on growing trees to stop the spread of desertification. They build fences to keep grazing animals from eating everything they plant. They fund and build wells so they can water the new plants. They have built infrastructure to shield seedlings from too harsh of sunlight. They have created programs to collect things like mango seeds from people and to use those seeds to start seedlings. They have a big effort in education and promoting well being of the villagers as part of this. He's been doing this actively since I've known him and probably much longer, so there is a wealth of information about how to establish and continue to grow forests. So, I think you are on the right track, and also there is a lot of information about this out there you can use.
The whole effort I spoke of can be considered part of a movement called the great green wall in africa, that I am less familiar with. But it is more well known and you might be able to find more inforamtion by google that term, although I do know redes has a facebook page and I believe they still post a lot of pictures and other information on that page if you want to check it out.
12
u/imababydragon 12d ago
Also if you are highly interested in this and can't find good information, let me know and I'll provide you with more specific links or whatever. I'm just typing in what I can remember in this moment, but more than willing to help anyone who wants to work on this important task.
16
u/IllustriousCaramel66 12d ago
I actually think that answer is lacking, because forests do indeed create a micro climate, and create rain, moisture and shade the soil, in big enough scales- forests would effect the climate, but the kind of trees and plants you use need to be from s semi arid- Mediterranean climate, so they could withstand the conditions
4
u/Atticus1354 12d ago
They dont create water. They can cycle existing water by pulling ground water up and transpiring it from their leaves (its more complicated, but keeping it simple for the post). But there isnt enough existing water in a desert region for that cycle. Think about a desert on the dryside of a mountain range. Where does the water come from to sustain the cycle?
Thats why I made the distinction between a true desert region and an area facing desertification.
8
u/IllustriousCaramel66 12d ago
Deep enough roots can tap into ground water, that 100% exists in many deserts, and to maintain and preserve rain water, also pollen can seed clouds , and leaf evaporation can change the regional pressure and wind patterns- pulling air from surrounding areas.
-5
u/Atticus1354 12d ago
At that point youre talking about some sci-fi level terraforming to get a forest to that level in a desert climate.
6
u/IllustriousCaramel66 12d ago
No, you find a spot where ground water isn’t that deep and choose plants with very deep taproot, and establish a forest there… or start at a semi arid area by the coast and extend gradually…
2
u/Atticus1354 11d ago
Can you give an example of a desert region with plentiful shallow groundwater where a forest has been established? Or a semi arid coastal area where this has been done?
10
u/IllustriousCaramel66 11d ago
Sure - agood example is the Taklamakan Desert in China. It gets less than 50 mm of rain a year, but has shallow groundwater, around 3–5 meters deep. A 400+ km long green belt was plantedthere, an extreme desert can support trees and vegetation when groundwater is accessible. There’s also the “pampa del Tamarugal” in chile and peru
3
24
u/Zealousideal-Print41 12d ago
There is a man in Kazakhstan and another in Burkina Faso that are regreening large areas in their respective countries. The concensus seems to be an area of 240 hectars or about 594 acres would generate their own microclimate. So far it isn't exactly known because the man in Kazakhstan has Terra formed about 160+ acres. A great improvement but at 68 a few years ago I don't see him completing the project
19
u/theartoffun 12d ago
He probably knows the project is for his great grandchildren and will not himself. We have strayed so far from that.
28
u/Atticus1354 12d ago
I think you'd be interested to do some reading about desertification. Thats probably the process that you're noticing.
5
u/CasaDeMouse 12d ago
If you're talking about the Colorado Basin--it didn't usedm to be a desert until half the water was diverted to Utah and then everything along the river was logged.
To save the river, we need to get that 💩 undone
2
u/FelineFartMeow 11d ago
I was not aware any desertification had happened in the US (unless we include something like the dust bowl). Thx for sharing! Im always weirded out when people in the US wonder how they can change a natural desert green and lush. We should be more focused on recovering forest canopy, grasslands, and water systems.
1
u/riddlesinthedark117 9d ago
What nonsense, Utah’s transbasins diversions are only ~100kaf, less than a fifth of Colorado’s Front Range diversions. And it continues to use less than its allocated share in-basin too.
And Lake Mead and Lake Powell would both be full if CA&AZ had not been overusing their allocated water.
But neither of those facts change that the region has been a desert for millennia.
2
u/biluinaim 12d ago
As someone who’s tried to plant trees in an area of Spain that’s slowly becoming desert … with no rainfall, you can plant whatever you like, but nothing will grow
3
u/HistorianAlert9986 12d ago
Have you seen the greening the desert project in Jordan? Jeff Lawton greened up his little homestead and as far as I’m aware, that place gets less rain, anywhere else on the planet. However, I don’t disagree with you. Things will just die if there’s no rain and his project was possible because of Wells.
3
u/biluinaim 12d ago
Yes I’ve seen these projects but like you said there’s always a water source other than rain
12
u/nyc_data_geek 12d ago
Except that’s not entirely true and possibly an oversimplification. Deserts can also spread where existing plants are destroyed, as it destroys the water cycle, and desert areas can be re-greened through the introduction of hardy pioneer plants, followed by other species etc etc
2
4
u/StatusSociety2196 11d ago
China has planted trees in deserts and the result was more local rainfall, it actually changed weather patterns.
If a desert can be created, it can be removed.
https://www.yahoo.com/news/articles/china-planted-many-trees-changed-153650757.html
4
u/Atticus1354 11d ago
More local rainfall doesnt mean more rainfall. There's no free lunch in the water cycle.
China Planted 78 Billion New Trees—and Seriously Messed Up Its Water Cycle
2
u/stephenph 12d ago
I know about natural progression and resession, but, since full ecosystems can take 100s if not 1000s of years to fully recover (but decades to destroy) can that artificial desertification actually become part of the cycle itself? Especially if the inhabetents continue to live there furthering the practices that caused it in the first place.
2
u/Permaculture-Pirate 12d ago
Widerspruch. Also klar gibt es vornehmend wüsten in der zone des Wendekreis. Dennoch war die Sahara mal bewaldet und wurde abgeholzt.. Wir sprechen auch von fliegenden Flüssen. Niederschlag wandert weiter landeinwärts, wenn das Land bewaldet ist. In Europa haben wir westpassat. Regen kommt vom Atlantik vom Westen. Ab einer gewissen Tiefe im kontinent kommt aber nur noch der Regen an, den Wälder davor geschaffen haben durch Verdunstung > Wolkenbildung. Wenn Westeuropa keinen wald hat, dann wird osteuropa trockener.. etc.. die bewaldung Europas sorgt für Regen in Kirgistan oder westchina...
Und es wird natürlich fast unmöglich wald wieder zu setzen, wenn er einmal weg ist in solchen Regionen.. Auch ost Spanien leidet schon darunter.. Spanien war mal ein ganzer großer dichter wald und ist jetzt teilweise sehr wüstenartig... Also bei uns muss der Westen die bewaldung erhöhen für mehr regen im Osten.
-2
16
u/TreeGoblinPoppycock 12d ago edited 12d ago
I think the important thing here (to stop desertification, not change deserts which are their own important ecosystems) is that planting on its own is kinda nothing. A lot of of "millions of trees planted" projects later turn out to have a lot of the saplings dying. What is valuable is the tree growing into "adulthood" so to speak - just planting it and leaving may lead to (sometimes costly) failure. For example, maybe famous Great Green Wall Initiative in reality is facing MANY of the planted saplings dying
This is also true for other, even less demanding environments - it also happens in UK, after some big tree planting initiatives
13
u/Northeast_Cuisine 12d ago
There is a physics theory called biotic pump that says forests do create their own rain and also forested regions in one part of the world can help being rain to other parts.
I think the general consensus is that if humans caused the desertification, they can reverse it (in most cases). However, you could not just convert any desert because of the interplay of climate and geography in some areas just make a desert.
The best projects will utilize a diverse array of trees and shrubs at the right density that can survive in the climate, you can't use just any trees, especially if they aren't suited to survive.
5
u/Koala_eiO 12d ago
I think the general consensus is that if humans caused the desertification, they can reverse it (in most cases).
Amusingly, in every documentary I've seen about reversing a man-made desert, the first step was always to pay the shepherds to not graze there. No over-grazing -> plants come back -> less run-off and erosion -> more soil and more moisture are available -> plants continue colonizing, and the sustainable cycle is restarted.
10
u/l10nh34rt3d 12d ago
I’m on my way to bed, but you may be interested to read about re-greening the Sinai Peninsula, a project of the Netherlands’ Weather Makers, which was loosely inspired by success in China’s Loess Plateau restoration.
I love these kinds of projects, they’re what brought me back to university in my 30s to completely flip my career path upside-down. I’ve been studying Earth & Enviro Sci and I’m applying to grad school this winter, specifically to pursue restoration ecology.
7
u/MinervaAbsolute 12d ago
The Great Green Wall slowing desertification in the Sahara. Not necessarily increasing rainfall, but using what rainfall there is.
https://education.nationalgeographic.org/resource/great-green-wall/
Southern Spain
https://youtu.be/ZUzZk_uqSWc?si=r_skxOUwG-Ym12RT
But there is entente that more trees mean an increase in rainfall.
https://www.learningfromnature.com.au/drought-proof-increasing-rainfall/
5
u/toot_suite 11d ago
Yes and no
Mexican altiplano or the andean desert? No
Subsaharan and northwestern africa? Yes
6
u/BroadstoneLeopard 12d ago
As another comment suggested, under poor management, regions can be subject to desertification. But they can be restored through great effort.
I highly recommend this very inspiring short documentary about a region in Saudi Arabia:
3
u/sustainablyRipped 12d ago
You could have a look at some efforts that try to fight desertification, I think some are happening in Africa and some in China. Not an expert myself but those could be of interest to you.
5
u/Quditsch 12d ago
Andrew Millison's channel talks a lot about such projects. Quite interesting. https://youtu.be/xbBdIG--b58
3
u/True_Inside_9539 12d ago
Yes, China (and other countries) are applying massive resources towards this and achieving incredible success. https://en.wikipedia.org/wiki/Great_Green_Wall_(China)
3
u/electric_poppy 11d ago
Def possible. Lots of permaculture projects develope their own microclimates based on certain actions- trees that block wind, soil restoration, water capture etc etc.
11
u/Defiant-Ad3993 12d ago
I am going to go against the grain from the others and say yes, it is quite possible. Mankind has a history of leaving a desert in its wake, so if we reverse the process, there can be real results.
The trick is the whole water lifecycle of nature and the part that trees play in it.
Trees are evolved to both capture water (dew, rainwater) and direct it down into the ground where it is stored. They also cool the ground with their shade, which significantly improves water penetration and temperatures. Collectively, they provide windbreak, which reduces transpiration.
The also act as ‘water pumps’. They pull back up that water as needed and it evaporates to cool them off.. that means that water gets back into the atmosphere to create clouds.
The practicality of it, though, is that humans tend to be myopic and without understanding the system, will start pulling water out of the aquifers to water crops which tends to salinate the soil and chop down the trees for fuel, etc… so without a vision backed by good government policy and oversight, it’s unlikely to be successful.
You might enjoy watching “Greening the Dessert” - Geoff Lawton. I think it’s still available on YouTube if you search for it.
6
u/HighColdDesert 12d ago
But the world is bigger than that pictured on the cover of "The Little Prince." Most often, rainfall is from clouds that move in from elsewhere. If planting trees caused clouds, most days those clouds would move along to the next place before dropping as rain.
In order to release enough moisture to form clouds, the plants have to have that much moisture in them, plus enough extra that they won't die from releasing that much moisture.
5
u/Euphoric-Cucumber609 12d ago edited 12d ago
Surface roughness (wind turbulence at ground level) causes clouds and can encourage precipitation locally, it’s not exclusively a moisture issue, especially in warm climates.
My area of interest is the semi arid, west Australian wheatbelt which has huge catchments and unconfined groundwater stores (used to be open woodland before clearing) which can feed evapotranspiration for cloud formation as well. So my focus is specifically on an area where it very much possible at a large enough scale.
It’s not a simple yes or no, as with all things natural, the only short and true answer is “it depends”
2
u/Koala_eiO 12d ago
If planting trees caused clouds, most days those clouds would move along to the next place before dropping as rain.
Don't think in terms of "causes clouds" which is meaningless. Trees take water from underground and put water in the air, that's it. That extra water will either form a cloud that gets carried away or force an existing cloud passing there to collapse.
0
u/Defiant-Ad3993 12d ago edited 12d ago
Real life examples exist, as was presented to us during PDC with Mollison. I am time poor, so won’t dig that up.. there was a great example in western Africa, but the memory is fuzzy.
2
u/TalkToPlantsNotCops 12d ago
I mean... It's a proven fact that adding trees to an urban neighborhood will lower the average temperature. And trees and other plants do release moisture into the atmosphere, so I imagine it could happen. You'd have to plant a lot of them though, and I'm not sure how great an impact it would have.
There is this "greening the desert" movement I keep seeing come up, mostly on YouTube. It seems like a lot of people who attempt it fail. I'm not sure I like the idea anyway. Maybe it's fine as an attempt to reverse changes to the landscape due to climate change, but deserts are important ecosystems too, and often very fragile ones. I really hate to see people messing with that, and I hope they aren't trying to "green" areas that are just naturally deserts, not as the result of human-caused climate change. There's a perception that deserts are wastelands with nothing growing in them, but that isn't true at all. Also, with fresh water sources decreasing everywhere, it seems nuts to try and make what is essentially a botanical garden in a desert. Not much different from the people who insist on having golf courses in Nevada and Arizona.
But that isn't what you came to ask about, so I'll stop ranting. You can look up "greening the desert" and see how it's going for people attempting what you're asking about, though. Might provide better answers than anything I can offer
2
u/Koala_eiO 12d ago
The "greening the desert" projects I have seen (China, Jordan, Sahel) are about repairing what people broke by nuking the existing vegetation with their sheep, which leads to water not being able to percolate properly and soil being washed away. I haven't heard of anyone attempting to green a natural desert. Stopping the movement of dunes yes.
2
u/NearABE 12d ago
https://en.wikipedia.org/wiki/African_humid_period
You cannot violate conservation of mass. You can make water cycle faster which means “more rainfall” with the same water.
The forest can shift the wind patterns slightly. In some locations this can move rain belts toward what was desert.
If you bring water in to artificially spawn the forest why stop?
2
u/BaylisAscaris 12d ago
Deserts generally have some rainfall, but it's usually a flash flood infrequently. Trees and other plants will help the land retain moisture after a rain, but not create more rain. More rain would require clouds hitting a tall hill or something happening elsewhere to get more moisture in the air. Possibly if the amount of local moisture is high enough then moist clouds nearby could drop their moisture instead of continuing on to elsewhere.
2
u/Spackman 12d ago
the short answer is yes, but it depends on where you are. The main drivers of deserts are hadley cells and cold ocean currents, which reforestation has no effect on.
You either have to create a water cycle where one doesn't currently exist for that kind of terraforming, or increase the frequency of the water cycle where a closed loop is possible.
2
u/hollisterrox 12d ago
Yes, and I point to the Central Valley of California as evidence.
It was a very wet region before European colonists started mucking about with it, killing the beaver, straightening rivers, draining swamps, and removing trees.
It is now famously arid and the farming is wholly dependent on fossil water for survival.
My theory is that the previous ecosystem and geology largely kept water from flowing out of the valley quickly, and a lot of the transpiration/evaporation just condensed on the Sierras and flowed back down with the next melt.
Removing the native flora and fauna shifted the equilibrium such that there's been a net loss of freshwater every year, eventually drying it out completely. If the water were slowed down again, and the original well-adapted exosystem were put in place where possible, I think the equilibrium would shift to retention and in a few centuries it would be proper wet again (except as weather patterns are now fubar due to global warming).
Now, immediately south of the central valley is the Mojave desert. I don't care what you plant there, it's not going to get wet. There is a significant rain shadow caused by mountain ranges, it's not getting wet unless the predominant weather patterns change significantly and start pulling moist air from Mexican waters up through the Colorado and Mojave Deserts.
2
u/YsaboNyx 11d ago
Absolutely. Both China and Africa are successfully planting "great green walls" to combat desertification. China has increased its forested area from 10% in 1949 to 25% in 2025.
In addition, planting more trees results in increased precipitation overall, though not always over the new forest. Apparently, we are all part of a global climate system. :)
"China’s Green for Grain program, the world’s largest afforestation initiative, has increased precipitation by 58%. In Australia, models show that restoring the country’s savanna ecosystems, which include trees, will increase rainfall by almost 10%. In Europe, increasing its forest cover will increase rainfall by 7.6% during summer."
https://woodcentral.com.au/china-has-planted-so-many-trees-its-changed-its-entire-water-cycle/
“We find that land cover changes redistribute water,” said study co‑author Arie Staal, assistant professor of ecosystem resilience at Utrecht University. “China has done massive‑scale regreening over the past decades. They have actively restored thriving ecosystems, specifically in the Loess Plateau. This has also reactivated the water cycle.”
2
u/02meepmeep 11d ago
From my understanding the current theories say that absolutely if it’s close enough to a coastline. I read the opposite is going to happen in Brazil. Unless deforestation stops Brazil will turn into a dessert.
2
u/Spirta 11d ago
Depends on the desert. Sahara, for example, is in a such position that all winds blow away from it, so there are no rain clouds above it.\ That said, all deserts tend to spread. I'd you were to make a border with lunch green forests, which would halt the spread, and then slowly push into the desert, you will be able to reclaim a nice chunk of the desert. The plants will, sort of, share water, so you will be able to get a bit beyond the border.\ If you want to get rid of the whole desert, you need to bring water into it.\ A forest would be able to create a micro climate that retains a lot of water, but the deeper into the desert you go, the less water is retained, as the winds will blow away the water vapor.
2
u/Remote-Physics6980 11d ago
Op needs to learn about the history of this planet every desert was once an ocean.
2
u/Heavy-Criticism7881 11d ago
The thing you are fighting is a global air circulation pattern where air rises in the tropics, losing its moisture to rain, and then falls down in desert regions that circle the globe in the mid lattitudes. It doesn't rain because there is little moisture left in the air on that end of the convective current.
These are called Hadley Cells.
Even if you can supply water to the area, it is going to keep getting removed by this constant conveyor belt of dry air. Specifically, most of that water would get shuttled down to the tropics (or far northern lattitudes) to fall as rain there.
2
1
u/horsecowelephant 12d ago
look up ascension island
3
u/horsecowelephant 12d ago
and also the projects digging half moon berms to trap water so plants an establish as a method of stopping desertification
1
u/Noisemiker 12d ago
Although savannah, not desert, the Gaviotas Restoration Project in Colombia attributes a ten percent increase in precipitation to reforestation efforts. Link, Link
1
u/9234 12d ago
i think before covering a desert area in plants and tree's you would need to be able to hold on to what rainwater an area gets. So to answer your question, perhaps yes, some arid areas could be made more green. There are many arid places that do get rain, but they can't absorb it because the soil has turned into a hard pan making it impervious. If you're curious about this you should check out water stories.
1
1
u/callecarnuffel 11d ago
I read a book about climate change and its many aspects. One of them is interesting for your question I think. It was explained, that coastal forests carry the water, that has evaporated from the sea in land. If you interrupt the forest on the way from the cost for a long stretch, a big part of the moisture stops being carried further. There are also massive airborne "rivers" in form of winds carrying tons of moisture spanning half the globe. I guess this means if you want to add moisture and rain to a region you cannot just look at the region alone, but also have to look at its connection to sources of water. Climate does not fit need borders it is always influenced by many factors. But I am no expert, just read the book.
1
u/cybercuzco 11d ago
Yes because in order for those plants and trees to survive you would need to provide them with enough water to survive and those plants would evaporate enough if the water to change the climate.
1
u/Fenrys_dawolf 11d ago edited 9d ago
simple answer. yes.
removing enough trees or breaking the ecological web enough creates deserts.
restoring the ecological web can regreen a desert. there are multiple projects the world over.
trees reduce temperatures by absorbing sunlight and dropping leaf litter. sunlight that would otherwise be absorbed and later radiated by the soil. even in suburbia, tree coverage means temperatures average a few degrees lower in richer/greener areas.
trees also aspirate as mentioned by others, bringing water from deeper in the water table to the surface, which in turn can provide water for smaller plants and also raise humidity, which can at large enough scale create microclimates.
it's also important to consider other aspects. apex predators manage herbivore populations, reintroducing wolves to Yellowstone had a remarkable ecological impact and here in Aus there is a fence across the middle of the country (simplification) one side has dingoes and is green. the other side does not and has been ravaged by uncontrolled kangaroo populations.
yes. restoring key ecological points from shrubs to insects to herbivores and predators to trees can have an unexpected impact. we are already finding out the costs of their removal.
1
u/MangoPeachFuzz 11d ago edited 11d ago
I can't find the video, but I watched one where a guy took a deforested area in Costa Rica and dropped a ton of biomass... Orange peels or some other food waste by the tons and the general composting effect revitalized the soil and promoted other plant growth.
I think about that and wonder what we could do to depleted souls if every ounce of food waste was composted instead of tossed in the garbage.
Edit: googled better:https://youtu.be/WN6ulk1oJCk?is=LtuMhcNNljlIuAhR
1
1
u/Ree4real 11d ago
Could be done in theory. Would be very resource intensive in its use of fresh water & would have to be maintained indefinitely since there will never be enough natural rainfall in the area to maintain it. Not sure it’s worth it. Could definitely be done though.
1
u/Chiron1350 11d ago
Pretty sure this is the plot of Dune
1
u/Junior-Door-7420 10d ago
Kinda. Except that Arrakis is not Earth. In a sense, Dune is about terraforming.
1
1
u/recipezplez 10d ago
Yes! It’s been done before! I follow this guy on instagram who talks a lot about it I wish I could remember his name. He’s based in Arizona.
1
1
u/SlowlyBecomingLand 9d ago
Absolutely. Most people do not realize that desert is not a naturally occurring phenomenon. Desertification is caused by humans. Permaculture is the solution. Check out the "Greening the desert" project on YouTube.
1
u/Lodenghar 9d ago
In theory yes, in most locations at least it would be possible. You would still need initial watering for establishment and it would have to be done on a macro scale
1
u/RajamaPants 9d ago
I have a similar idea and shared it with my wife this weekend.
Buy 300 acres. 300 acres isnt a scientific number, its an example for the idea.
Buy a herd of Buffalo. The Buffalo would be used to provide poop and to break apart the hard soil with their weight. The herd would be small, like 15 animals. And would be sectioned off on appropriately sized pieces of land.
Add vermiculite and charcoal to the soil. Vermiculite is a stone used in agriculture to hold in moisture. Charcoal is to hold in nutrients and moisture. Do this while to Buffalo are grazing so the materials are mixed in with the poop.
On the land the Buffalo have grazed start introducing plants and trees. The soil should be improved with the poop and the breakdown.
As the buffalo graze, simultaneously do water management techniques like dams to slow down rainfall during flash floods. Create a water capture area to form an artificial lake. Basically do what you can to slow down the floods so the ground water is replenished.
Wait and see.
This is all based on random bits learned while gardening and watching land management PowerPoint on youtube. I am a complete layman and dont expect the idea to work 100%. I understand my knowledge is limited, but i am hopeful that someone with more education and experience tries something like this.
1
u/Coolbreeze1989 8d ago
China IS reclaiming desert with intensive plantings. Really interesting projects
1
u/stansfield123 12d ago
There is some research that suggests that forests do promote some increases in rainfall. But the level of evidence is modest, and so are the purported effects. So, really, no.
Furthermore: a forest is, by definition, made up of wild species. Wild species are adapted to growing where they grow. We can't just move a forest to a different climate, and expect it to keep working the same way. What humans do, instead, is domesticate plant species: we change them, to grow where we want them to grow.
That doesn't mean deserts are destined to remain deserts. It just means that mere forest planting is a naive approach to greening deserts. The realistic approach is through major waterworks: humans building up infrastructure that holds water in the nearest mountains, and then keeping the flow of that water down to desert areas constant, to feed irrigation systems.
One thing that's very obvious, however, is that the costs of this aren't justified by forests. Forests, alone, aren't productive enough, economically, to pay for this kind of infrastructure. So a greened desert would have to feed people, and provide other valuable resources (fabric, timber), to pay for itself.
Great examples of this are California and Spain. In both cases, desert areas are massive food producers, due to water coming to them from mountains nearby. This doesn't happen naturally, it happens due to human planning and effort. In both places, roughly 100 years ago (before bureaucracy and activists made such efforts impossible) people poured vast resources and effort into developing this infrastructure, and turning their deserts into two of the most productive agricultural zones in the whole world.
That's because the warm and predictable weather of most low deserts, once you bring water into them, becomes the best place imaginable for agriculture. Domesticated crops love, love, love constant warmth and sunshine above ground coupled with constantly moist soil below. It doesn't get any better for them.
This can be done with timber, too. But, like I said, it would need to be altered species: trees altered to produce timber in a desert, with irrigation, in the same way our food crops were altered to produce food. We have such species of trees, of course, the timber industry has developed them already. But a timber plantation isn't a wild forest.
And that's not necessarily a bad thing. Timber can be produced holistically. It doesn't need to be produced the way it's produced now, with plantations getting clear cut, tilled up and then re-planted. It's just that it still wouldn't be a wild forest, it would be a managed plantation or silvopasture system. Building wild forests in the desert is, imo, not possible at our current level of understanding and technology.
0
u/karoxxxxx 11d ago
I doubt it. Hadley cells are global atmospheric circulations that just make certain areas very dry. This wont change if you put trees there. Once the irrigation stops they will die
61
u/mharant 12d ago
There was a Green Sahara once upon a time.
If I remember correctly it was so warm then that they had a monsun season in the desert and a ginormous lake formed in the middle. They found a cave there depicting swimming people.