Pruning and Training - Growing Organic Orchard Fruits - page 616

As the trees mature, you will need to remove some of the scaffold limbs to
prevent crowding and shading. By removing older branches, you also pro-
mote the formation of new fruiting wood and spurs. One strategy for main-
taining mature trees is to thin out some of the largest branches each year so
that all branches are replaced about once every 5 years. To keep the trees
short, cut off vigorous leaders using thinning cuts, and tie up weak lateral
branches near the tops of the trees. This leader renewal method produces a
zigzag top and is a critical part of controlling tree vigor. Prune to maintain a
conic shape with a narrow top and a wide bottom. Figure 12.12 ➔ shows the
steps in training a tree to a slender spindle design.
Tall spindle design. The tall spindle appears to be one of the best high-dens-
ity axis designs today for commercial apple plantings and comes largely
from work done at Cornell University. This design is quite similar to the axis
and other spindle training systems described earlier in this chapter. Accord-
ing to Michigan State University's Crop Advisory Team, the tall spindle sys-
tem is excellent for eastern apple growers and has the following advantages:
▪ It is the most cost-effective, efficient apple training system.
▪ It produces significant yields of high-quality fruit in early and mature-
bearing years.
▪ It is highly adaptable to machine-assisted practices (pruning and har-
vest).
▪ It is a simple system and easy to learn.
▪ It fits the natural growing characteristics of a high-density apple tree.
▪ It captures the maximum amount of available sunlight.
▪ It has little to no shaded (or wasted) space in the tree.
▪ It maximizes yield per acre due to its tall (10- to 11-foot) tree height.
▪ It is one of the best apple production systems to maintain a low carbon
footprint.