Experts and BHG readers answer.
Injured minature Arborvitae
When you say that the lawn maintenance service cut the tree, do you mean that they damaged the trunk or cut off the foliage back to where it is brown? Arborvitae can sometimes resprout from a severe cut back, but, of course, it's best not to cut them back any farther than their green scaly needles. If the main stem was girdled or damaged by a trimmer, and the tree subsequently turned completely brown, it's unlikely that it will green up again even though the branches are still pliable.