in fruit growing and ornamental horticulture, imparting a certain shape to the crowns of trees. The crowns of fruit trees and shrubs are made light-permeable, sturdy, and compact to ensure high yields and convenience in managing, cultivation, and harvesting (by mechanized means). Crown shapes are classified as high-trunk (taller than 150 cm), average trunk (70–100 cm), low-trunk (50–60 cm), shrub (shorter than 40 cm), and trunkless (berry bushes and, sometimes, plum, cherry, and certain spreading forms). Depending on the arrangement of the branches, the crowns may be free-growing (improved-natural) or artificial.
Most common in fruit-growing is the free-growing crown, in the formation of which the natural growth of the tree or shrub is only slightly disrupted. Free-growing crowns include the whorled-layered crown whose principal skeletal branches are arranged in whorls of five in two or three layers, and the thinned-layered crown whose skeletal branches are arranged in layers of three, with solitary branches between them. Artificial crown shapes are used in topiary work and in ornamental horticulture. In beautifying city streets trees are usually trained to have a high trunk (up to 2 m) and a spherical crown. In parks trees are often trained in the form of geometric shapes, vases, and animals. Training is usually begun in plant nurseries and completed at the permanent planting site. The principal method of tree training is pruning.
B. P. ANZIN