A few years back, I undertook a revegetation project on my previous chunk o' dirt in rural South Australia. It was a fascinating experience propagating trees from seed - and a lot of hard work. 

The 300 trees were planted by hand in a semi-arid area and while the survival rates were high, a great deal of time went into ensuring that. 

Most of the work post-planting was maintaining the tree protectors and keeping the trees watered. I would fill up an old pickle barrel with water from my tank and then using a wheelbarrow, visit each tree to give it a meagre drink to try and help it in its first year. 

I hate to think how many hours I spent wheeling that pickle barrel around, but it was a labor of love. 90% survival was a good result, but it was always sad when one didn't make it given the time spent nurturing each plant and watching the tree's valiant struggle to survive.

Something like the Groasis Waterboxx would have likely helped improve survival rates even further.

The Groasis waterboxx (no, not a typo) captures rain and water from the air through condensation. It also acts as a guard against numerous threats to trees battling to establish themselves in harsh conditions. 

The tree is planted at the bottom of the waterboxx cylinder. The waterboxx harvests condensation and collects rain water which it distributes to the plant in small quantities on a daily basis. The waterboxx also acts as protection against evaporation, frosts, pests and the elements and also helps to maintain a steady temperature at the tree's roots.

When the tree is old enough to stand on its own two legs so to speak, the waterboxx can be removed and reused.

The Groasis waterboxx was tested for 3 years in the Sahara desert and trees that were planted during the summer with the waterbox survived well, but the test without the device saw 90% of those trees die, even with weekly watering. 

The creators say the waterboxx was inspired by nature - the clever design that some plants use to capture and store water. 

I could certainly see something like this also working out on my current patch (which thankfully doesn't need revegetating though). I don't see much rain, but I do get rain "events" where it will bucket down for a couple of minutes and I'll be surrounded by water - but within a few hours most of the ground looks like nothing happened. While the older trees have deep roots and collect that moisture, the young 'uns don't get much of a chance for a drink.

You can buy the “Groasis” waterbox in small or large quantities. At the time of writing, purchasing in units of 10 costs around USD$27 each (ex. shipping), but if you can get a group together, they are as little as $8 each ex. shipping. That's for around 7,000 waterboxes, so I guess you'll need a large group! You might also want to try approaching your local nursery to see if they can get them in. Buying a container of them could also be quite viable for tree farming operations where water and time are valuable and limited resources. 

It really is a fascinating invention and the animation on this page explains how it works very well. The units are made of polypropylene, but I remember reading somewhere that a "compostable" version is also in the works.
 
Related:

Tips for saving water in the garden