Those are water intensive trees will die within 1 year if they are not given sufficient water wiping them out for good. These tree will probably be kept alive for a few years if they are sustained on a small amount of water but then if the drought continues they wont survive. There is also massive water saving measures that can be taken by the suburban, and residential use as CA are using 5 times the water as Australia. Ca needs a long term solution though, as the world heats up and changes. Eventually water usage problem will be resolved one way or another.