Question
I have twin oak trees seperated ground level, one is 39" the other 50" in circumference and they produce acorns, not all our oak do, I heard they are red,white and black oaks on our area. Had a vindyl deck (no space between boards)built up to them last year covering half of the root system,  Do I water under the deck for the roots and how far out from trunk? I live in south jersey, zone 6.  This is more info, system sent my email before I clicked.  Thanks so much

Answer
Continue for the previous question--With no space between the boards there will be no water under the deck. I would water the trees. It is going to be difficult to water under the deck without but I would do this. The ideal thing would be place a pan under the tree and turn the sprinkler on and when the pan has 1 inch of water in it stop. Do this once a week if it does not rain. I think the tree will adapt and get its water from the exposed root system.  I would supplement water under he deck at least every other week during the growing season. This is a difficult question with out seeing the set up but this should work fine.