You are here.
Tree Support Systems
As apple growers move to higher-density production systems using more dwarfing rootstocks, tree support becomes more of a concern. Most of the very dwarfing rootstocks require support, but there are somewhat more vigorous rootstocks that can perform well without support under certain conditions. However, depending on cultivar, soil type, slope, vigor, and cropping conditions, support may be necessary for semidwarf stocks.
Support systems should be installed soon after planting. In some situations they can be removed later after a strong framework of branches has been established. Some trees, those which have been supported for a few years, may stand on their own because they were initially supported and therefore developed a large, intact root system.
The cost of tree support systems varies widely. One system being used with Fuji in Pacific Northwest orchards of extremely high densities is the V system with a minimum system of posts having two wires with a small bamboo stake at each tree. Some of these systems are extremely expensive. Several systems of tree support and their associated costs are presented to illustrate costs. Below are some comparisons between various tree densities and types of possible support systems. The support systems are: a 6-foot, four-wire trellis system, a 10-foot wooden post without any wires, a 10-foot small diameter conduit (0.706 inch diameter) with a support wire at 6 feet, and a 10-foot large diameter conduit (0.922 diameter) also supported by one wire at 6 feet. One example is given of this larger conduit without a supplemental support system.
The costs of the components used in the above systems are as follows. For end posts a 3- to 4-inch diameter by 8-foot-long wooden post ($4.85) is used in conjunction with a locally procured anchor ($4.00) for a total cost of $8.85. Line posts are pressure-treated wooden posts, 2.5 to 3 inches by 8 feet, at a cost of $3.35. Wire used for all systems is 12.5-gauge, high-tensile-strength wire with a class 3 galvanized coating at a cost of $0.018 per foot. Individual tree support systems include the following types: 10-foot small diameter conduit at $1.35, the 10-foot large diameter conduit at $1.75, and 2-inch-by-10-foot wooden post at $2.95. All systems illustrated were designed for 300-feet rows with line posts spaced at 40 feet. Shown in the following table on a per acre basis are the cost of wire, the cost of end posts, the cost of line posts, the cost of tree stakes, and the total cost of the support system.