Hacker News Reader

Comment by ai_ia | Hacker News Reader

I wonder if desert soil can be gradually converted to make the land fertile. That would definitely be helpful to convert a lot of land to plant trees which is currently of no particular use.

Any research or innovation on that front ?

View on HN

The soil is generally fine, the limiting factor is water. In Central Oregon's "Lake County" near where I live, 10-20k years ago was dense forest and thousands of deep clear water lakes. It's all desert now except for the "Lost Forest" near Christmas Valley. A fascinating enclave of ancient trees that somehow survive in the middle of the desert due to what is suspected to be an unusually shallow ground water system.

I’ve heard that a critical mass of trees can effectively generate their own moisture and counter desertification. No idea how this works or if it is true, but I’d love to be corrected and/or learn more.

China tried it and it's not really working https://en.m.wikipedia.org/wiki/Three-North_Shelter_Forest_P....

Also looks like a similar project in Africa https://en.m.wikipedia.org/wiki/Great_Green_Wall

Water would be a problem, although that could theoretically be solved with solar powered desalination.

References: https://en.wikipedia.org/wiki/Desert_greening

That’s a really good point also where water and irrigation is concerned hopefully that would be done in the most sustainable way possible.

You need light, water, micro and macronutrients in right amounts.

Desert greening is essentially question of water availability and reversing soil erosion but you may also need the nutrients.

There have been many attempts in desert greening and oasification but they are expensive and have not been very successful in large scale. It's much easier to create a desert than do the opposite.

The Sahara desert is already being reclaimed at a remarkable rate by the people living at its edge, just to get more farmland for themselves. The more trees you have, the more precipition is collected.

Many places we think of as ancient deserts were climax forests in historical times, such as Petra. It became desert when too many trees were cut.

Ahem, how about the Sonoran?

Couldn't say.

You'll have to account for driving water to the desert. Desert soil is fine (for desert-aware trees), but trees like water, and large trees like lots of water. In my country, Australia-native Eucalyptus is doing well.

http://www.kalanit.org.il/wp-content/uploads/2016/10/IMG_000...

The Romans built aqueducts that spanned hundreds of miles and they did it thousands of years ago. Why do you assume that today water has to be 'driven' with trucks or something?

I'm sure we could build aqueducts.

Whatever you do, if the target is reducing CO2 emission, you'll have to account for the CO2 investment. All I am saying is it may be more cost-effective to leave the desert alone and put our Trillion trees where conditions are already great for large trees (Alaska, NZ), instead of pipe-dreaming about Roman aqueducts delivering water to a green Sahara or Gobi.

Yes

https://youtu.be/stc5MUIloP0

Reply on news.ycombinator.com