Cutting Stock for Top Graft
A tree may be made over by cutting off its entire top, and grafting cions to form a new head. Mr. Burbank recommends that the cut edges be smoothly trimmed for this and for all other grafts. The additional time and effort required to smooth the cut surfaces with a knife will be amply repaid by the better results attained.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 3 Chapter 5