Sprouts form from callus or meristematic points. Also see pollarding. After the structure is established with a pollard, sprouts are pruned every year. Sprouts unlike branches, do not have a branch collar. However there is a swollen area at the base. When removing a sprout, remove it back to the swollen area without leaving a stub and without injuring the swollen area at the base.
Although sprouting occurs when trees are over pruned or stressed, some trees, such as this sycamore tree above, is a prolific sprouter. The lower right sprouts (below) formed from the callus as it formed about the pruning cut.
