I agree if it is dry and you have a young tree, less than 3 years old, water to make it happy. As many of you know, I grow Chinese Chestnuts and a few Sawtooth oaks. I have been known to water in December and in March due to dry conditions. I have been lucky to not have many die on me. Although the deer have killed a few but that goes with the territory.
For some pear trees that are about 7 years in the ground, I have stuck some PVC pipe in the ground to give the roots more moisture this year. I am hopeful to see if I can improve what they produce for the deer herd. None of those pears make it to the kitchen table.