Macadamia Nuts in Hawaii: History and Production - ctahr ...

original 70 trees are still in production. In view of
this demonstration, Castle & Cooke planted an
additional 1000 acres (405 hectares) in squares 30
feet (9.2 meters) by 30 feet (9.2 meters), with an
additional tree planted in the center of the square
for a total of 96 trees per acre. The additional trees
are to be eliminated in 20 years or so, to result in a
square orchard with 50 trees, 30 feet apart, per acre.
The original trees at C. Brewer in Ka'u were
planted in the 1960s in a 25-foot-square pattern to
give 70 trees per acre. Beginning in the late 1970s
planting has been in rows spaced at 25 feet and
trees in the row spaced at 18 feet, giving each
planting area a square footage of 450, or 97 trees
per acre. When the closely planted trees are alternately
eliminated as they close in and begin to
shade each other, the ultima te diagonal distance
between trees will be an adequate 30.8 feet, which
should be the permanent distance between trees in
a mature orchard at 48.4 trees per acre.
Dense planting to advance development of an
early cash flow, and subsequent alternate-tree
elimina tion as the orchard trees begin to close in,
is economically very sound; it should be practiced
universally. In an orchard operated under a corporate
structure, where the operations are done on
a relatively large scale and very impersonally, the
design of planting and subsequent tree elimination
are agreed upon prior to planting. Consequently,
tree elimination can be done without any
second thought when the orchard closes in. However,
on a smaller farm where the owner also operates
the farm, tree elimination can become a difficult
issue since it can temporarily reduce yield
when done drastically. This becomes a problem
44
especially when the tree to be eliminated happens
to be heal thier and better than the permanent trees
next to it.
Anticipating a difficult decision at a later date,
the permanent orchard can be completely laid out
initially in an equilateral (quincunx) design to
make the best use of the spaces between trees. This
decision is a compromise at the start, which enables
the orchardist to know exactly where he is at
the beginning. Figure 57 graphically illustrates
the loss in land area utilization when the trees are
planted in a square rather than in an equilateral
triangle. A reasonable assumption is that a tree
with branches emerging in all directions will grow
in a more or less circular, ra ther than triangular or
square, pattern. If this assumption is correct, the
large "dead" area among four trees in a square can
be expensively underutilized. This "dead" area
can be much reduced by using the equilateral
planting scheme. For example, in a 30-foot-square
pattern, each tree is allocated 900 square feet of
land area. On the other hand, with the same distance
between trees, 30 feet, in an equilateral
triangular pattern, the distance between the rows
of trees will be 26 feet. Trees in this pattern will
then be allocated 780 square feet. Expressing this
gain in number of trees, a 30-foot by 30-foot square
will allow only 48 trees per acre, while the 30-foot
equilateral triangular pattern will allow 56 trees
per acre, an increase of eight trees, or 17 percent.
Perhaps this is a better way to increase early and
continued production.
Another essential factor in tree spacing is the
growth habits of the trees. Some of the selected
clones are more dome shaped, and some more
Figure 57. Graphic representation of planting design to illustrate space loss in a
square planting compared to the equilateral triangular (quincunx) system.