Once a live tree is cut down, the roots soon stop growing. There is no longer the stimulation from hormones produced in the canopy to encourage new growth of roots. In most cases, the roots stop growing within a matter of days or weeks, and usually die shortly after that. Some tree species develop root sprouts, however, pushing out new stems from the root system. If allowed to grow, these shoots will produce the hormones and the carbohydrates the roots need to survive. Simply mowing the sprouts as they develop will usually result in the final death of the root system within a few months or a year.
Mechanical routing is the quickest method of stump removal. Stump grinding machines generally operate with a large flywheel equipped with cutting teeth. The operator moves the cutter head over the stump, grinding it away a little at a time. The machine is designed to work in tight places.