I was impressed to see over 30 new buds springing from the stump of a young hawthorn tree I had severely pruned (planted in wrong place, oops). This was about 2.5 months after cutting. I believe these are termed adventitious buds, which are dormant buds springing into action if the tree is wounded, for example by incompetent gardeners, or more planned activities like coppicing and hedge laying.
Feb 2017 +2.5 months after pruning
I'm hoping to keep the tree small in case the roots damage a nearby wall, and I intend to add photos to update the tree's progress in surviving my pruning.
One of many information sourses on www
April 2017 +5 months after pruning (shoots ~ 20cm long)
July 2017 +8 months after pruning (shoots ~ 30-40cm long)