Developing a bonsai requires many steps. One critical step is allowing the bonsai in development to grow wildly. This allows the tree to gain strength and to form branches that will be used in its development.
Periodically the overgrown tree will be trimmed back, given a haircut to bring the design back to a more compact design while also keeping the needed branches and eliminating the ones that are not necessary. This process is repeated until the later stages of a bonsai’s maturity.
Once mature and the design is set growth is kept more restrained. The cycle of growth followed by trimming back is kept up for many years until the tree hits maturity when a more restrained growth and tim back cycle begins.