I have an established elm tree in my yard. A porcupine made a habit of visiting it last year but is has ceased it's visits this year. This year it seems as if it is being challenged with not enough water. I'm thinking about putting a hose around the crown base for moisture. Is this a wise move? It needs water I think. Any suggestions?
Don't water just near the base of the tree. Water the entire absorbing root zone, which extends at least as far as the foliage.
When you say a porcupine visited the tree, did it do some damage to the bark and underlying growing layer? If so it may have damaged the vessels that conduct water and nutrients to the foliar crown, and that could be a reason for decline.