As for local or regional scales, yes there could be impacts. I'm not quite as well versed in how trees affect the environments, but I suspect a local water-from-air farm would have some impacts on a local scale. If we had some data on how redwood trees absorb based on the different environmental conditions, I could run some numbers to figure out the differences and see how it would be affected.

Agreed on the impacts though, this isn't a zero impact technology, but compared to the direct competitors it is trying to replace (groundwater harvesting or desalination), it is an improvement. A mindset I like to apply is that humanity will need water regardless of how they get it. New technologies should provide a solution that is lower impact, along with a financial incentive (cost).