[dmos62]

Here's an interesting case study about a plantation in a dry ski resort. It has more info, which is otherwise a bit hard to find: https://www.youtube.com/watch?list=PL5MDcgMmY2CXV3x-v0KCjMd1...

Notice, that it's a playlist with a bunch of these case studies.

The device displayed in the video (the company makes a few different ones) didn't require watering at all, because it collects dew. It's also biodegradable, so there isn't a cleanup cost. They also provide physical protection for the sapplings, which can be important. It seems to add up to very high survival rate in tough environments.

Edit: here's a brochure explaining the technology: https://issuu.com/groasis/docs/brochure_eng_2

[farseer]

Dew collection at night and massive evaporation of the Sahara during daytime. Not sure if this would be enough to sustain a medium sized tree. Whatever works in Netherlands may not work in Egypt.

[dmos62]

The collected water does not evaporate. The linked case studies are in extreme climates, like a 1500-1900 meter altitude mountainside or a desert in Spain, not central Europe.