Deeply water trees with a slowly tricking hose or slowly running sprinkler left in place for a couple hours. Apply the water slowly enough that it can soak in and not run off. Winter is a difficult time for trees. Trees must stand in the face of drying and cold winds. Food reserves must be carefully conserved for the coming needs of Spring.
Water continues to be lost from the tree.
Any creature needing a meal chews and nibbles on the resting buds and twigs. Trees stand alone against all adverse circumstances the winter season can generate. Trees are important investments in your landscape and they do require a small amount of care. For the sake of your tree's quality of life and your own, take a few minutes to winterize your tree.