
Box elder rarely looks healthy, so the question is never 'is it stressed' but 'how much sound trunk is left.' Sound the base for hollowness, look for seams of included bark at the low forks and any fungal conks — a box elder with a dead top and a punky base is finished, whereas sparse cupped yellow foliage on a stressed one will often bounce back and buy several more years you probably do not want it to have.
Almost nobody plants this — it arrives as a volunteer in a fencerow, along a back fence or six feet off a foundation, and by the time anyone notices it is a thirty-foot tree with brittle wood and a rotting center. It is also the source of the box elder bugs massing on the sunny south wall every October, and extension guidance on that is blunt: removing the female tree is the reliable control.