30 ~ 35cm. Oranges are hybrids of grapefruit and oranges. The trunk of the orange tree is fixed at 30-35cm, and 3-4 spring shoots with proper orientation, uniform distribution and strong growth are selected as the main branches. When the branches grow to 30 ~ 35 cm, the weak parts at the top are cut short, and three branches are cultivated on each main branch as the first-class side branches.