I'm not a botanist, but if they are experiencing drought then how will these newly planted trees survive? According to the article they are so low on water they are slashing output on their hydro-power system and ceasing electricity exports.
A great example of transforming large tracts of land is the UVM Jericho research forest in Vermont. It was farmed for nearly 150 years, its soil degraded to the point where it was sandy and barren. I've heard it described as a moonscape. After planting 70,000 trees [1] and letting nature do its thing, it now resembles an old growth forest. It's a prime example of nature's capacity to heal itself and is a source of hope for me in the context of climate change.
0: https://en.wikipedia.org/wiki/Microclimate
1: https://www.uvm.edu/rsenr/jericho_research_forest_and_conser...
An example would be olive trees, but hey there's a whole wikipedia article about it that definitely knows more than me:
https://en.wikipedia.org/wiki/Desert_greening
"Trees store water, raise water from underlying aquifers, reduce evaporation after a rain, attract animals (and thereby fertility through feces), and they can cause more rain to fall (by temperature reduction and other effects), if the planted area is large enough."