FAQ - Answer
As a general rule of thumb 50% of a trees root system is found within the dripline, 50 % outside of the zone. For ease, the drip line is most often delineated as a circle around the outside of the existing dripline. The roots will remain static following pruning, I wouldn’t assume they move in and out in a reactionary mode following pruning. In other words, before any pruning when you establish the circle identifying the root zone it would remain the same after pruning.