Let's pretend the next few things are limitless: time, water, and my awesome strength. In that pretend place, I could plant as many trees as we can currently imagine wanting. Here's the math that makes me question just how many trees I can plant.
If each tree needs 5 gallons of water every day for 4 to 6 weeks and that much water 2 to 3 times a week throughout the first season, and maybe all of the second season, too, that's a lot of water even for just one tree.
My friend has a pond and she fills buckets at her pond and then hauls the filled buckets to her trees. It is admittedly difficult work, but it's pretty darn quick to fill a five gallon bucket from the edge of a pond. I would have to stand at the hose filling my imaginary bucket. Oh, and I should mention that my hose water passes through my pressure tank. I could also use the frost free hydrant (much better choice). It is still going to take some time to fill the five gallon bucket.
Then I have to haul the bucket to the trees. Yes, I could run that hose out to the trees, but that would take yards and yards of hose and we would probably have questionable pressure, making the filling of the bucket still slower. I also have not investigated the frost free hydrant, and I know next to nothing (at the moment) about such things, so I do not know if a hose can be connected to it. Definitely worth investigating.
This year, I only want to plant twenty fruit trees, five "shade" trees, 40 hazel bushes, and 26 berry bushes. Then there's the two big gardens and various other garden spots around the house. Let's pretend again for a second that I plant all those trees and bushes and that the garden will not ever need water. Let's also remember that one gallon of water weighs roughly 8 pounds. Each of those 91 trees and bushes would take 40 pounds of water a day for the first 4 to 6 weeks, hauled somehow by me and the children. That equals 3640 pounds of water a day. I'm pretty sure that my plans are a bit grandiose.