Configuration of the Tree Shape in a Bi-axis Apple Orchard using ‘Fuji’/M.9 Grafted Plants – Tree Growth and Productivity during Early Years According to the Planting Distance

This study was carried out in a bi-axis apple orchard with various planting distances (between- and within-row spacing at 3 m×1.5 m and 1.2 m, 1.0 m, 0.8 m, respectively) using ‘Fuji’/M.9 grafts to manipulate the tree shape during the early years of the orchard’s lifespan (up to four years after planting) and to compare tree growth outcomes and initial yields according to the planting distance. The configuration of a bi-axis tree shape with a narrow canopy width requires pinching of the shoots during the growing season, the removal of water sprouts or branches competing with the main stem after August, and the shortening of overly long/thick branches or renewal pruning in winter. In the early years of orchard establishment, vegetative growth decreased as the planting density increased, whereas the formation of spur-type fruit-bearing branches tended to increase. The light interception during the fourth year of planting was 37–42%, and there were no differences between the planting methods. The cumulative yields (kg/tree) were 8.7, 9.3, 9.9, and 10.3 at planting distances of 1.5 m, 1.2 m, 1.0 m, and 0.8 m, respectively. The yield increased with a decrease in the planting distance. In conclusion, the results here suggest that the bending of branches during the configuration of the tree shape in bi-axis orchards is not necessary. Until the fourth year of the establishment of the bi-axis apple orchard, with an increase in the planting density, the vegetative growth decreased, favoring fruit formation and an increased cumulative yield per tree. At a planting distance of 0.8 m, however, tree vigor was reduced slightly.