Brad Landcaster lives in Tuscon and has successfully been able to implement the rainwater harvesting methods to provide substantial shade in his neighborhood. I

Brad Landcaster lives in Tuscon and has successfully been able to implement the rainwater harvesting methods to provide substantial shade in his neighborhood. It's not just planting trees, but changing the conditions to support a forest ecosystem. Water retention has a lot to do with whether water gets absorbed into the ground, and the best way to do this is provide organic matter. Here is an example, this one from Andrew Millison talking about how the central canal project of Arizona accidentally created a condition that naturally supports a forest along the canal structure. It isn't because the canal leaked, but because the canal forms a berm structure, which then accumulated enough organics to retain the monsoon rains, that then jumpstarted the succession to a forest: https://www.youtube.com/watch?v=jf8usAesJvo https://www.youtube.com/watch?v=jf8usAesJvo