a protective belt of trees surrounding an orchard or sections of an orchard; rows of tree windbreaks may also be planted inside an orchard. Windbreaks diminish the drying effects of wind, hold snow, improve conditions for the growth and fruiting of trees, and protect ripening fruits from scattering when there are strong winds.
There are two basic types of orchard windbreaks: open and solid. The former allow more even movement of the wind and, consequently, better accumulation and distribution of snow in the orchard. Solid windbreaks retain cold air, which is particularly harmful to flowering fruit trees during spring frosts. In orchards with natural protection windbreaks are usually planted in two or three rows, in orchards in open areas in three to five rows, and in orchards in especially windy regions in six to eight rows. The rows are set 2–2.5 m apart, and there is a distance of 1–1.5 m between trees (0.5–0.75 m between shrubs). Windbreaks inside an orchard are planted crosswise to prevailing winds and consist of one or two rows of poplars or some other tall, rapidly growing tree species. The fruit trees and the windbreaks are planted no closer than 12–15 m from each other. The windbreaks are planted two or three years before the orchard.
In northern fruit-growing regions of the USSR the trees most commonly used for orchard windbreaks are spruce, pine, fir, larch, birch, linden, poplar, willow, and hawthorn; in the central region of the European USSR, pine, fir, birch, elm, poplar, maple, acacia, and honeysuckle; and in the southern regions, poplar, aspen, horse chestnut, elm, sycamore, honey locust, and oleaster.
REFERENCEPlodovodstvo, 2nd ed. Edited by V. A. Kolesnikov. Moscow, 1966.
E. V. KOLESNIKOV