A tropical tree might well have growth rings, since rings show when growth slows. In the tropics, in the absence of a cold winter, variation in water availability on a seasonal basis could also produce annual changes in growth and, thus, growth rings. If water availability were constant in a particular tropical setting, growth rings might be indistinct or absent.
Work Step by Step
To get to this answer, first review growth rings and what causes them. Then try to imagine a way that the same kind of growth slowing might occur in the tropics.