Question
Just planted a 12 foot red oak.  We put two lengths of 3 inch PVC into the hole down to the bottom of the roots.  Should I use more water than simply filling the PVC once per day?  Northern California Sierra mountains @ 5000 feet.

Answer
A much better way to water would be to water with 1 inch of water-place a pan under the tree and turn the sprinkler on and when the pan has 1 inch of water in it stop. This will give water over the entire root system not just in two areas like the PVC pipes will do. IF you have not done so mulch around the tree with not more than 3 inches deep of organic mulch not piled up on the trunk. This will help hold moisture around the roots. I would water every third day for a month then every week until the hardwood leaves fall. Then next spring once a week if it does not rain.