THE MACADAM I A NTT IX HAWAII 15 
season. The row which is next to the Macadamia orchard should 
consist entirely of ironwood. The horizontal roots of these trees 
can be prevented from entering the soil occupied by the orchard 
by maintaining a narrow ditch 3 to -1 feet in depth at a distance 
of about 4 feet from the row of ironwood trees. Preventing the 
spread of roots on one side of the ironwood trees does not have any 
serious effect on them. 
PLANTING 
In setting an orchard of either seedling or grafted Macadamia 
trees, care should be taken to use only those of good form and 
vigor. In most parts of Hawaii pot-grown trees are preferred to 
nursery-grown trees. Sterilized soil of a desirable mixture should 
be used in developing the former. Such soil is practically free 
from nematodes, insect pests, plant diseases, and weed seeds. Very 
little control of these enemies is possible in the field. The containers 
of small trees may temporarily be kept on slats placed on the ground, 
or the pots may be set on plant benches. Potted seedlings can be 
given individual attention and protected against irregularity of 
growth and the attacks of the leaf roller (Amorbia emigratella), 
which sometimes is found on the newly developed leaves. In places 
where nut grass (Oyperus rotwidus) can not be controlled in the 
field, it is likely to rob the young trees of plant food and greatly 
to interfere with their cultivation. Pot-grown trees are also easily 
grafted and may be given special attention during the transition 
from seedlings to standard trees. Trees of the Tropics do not 
have a period of dormancy as do deciduous trees of the Temperate 
Zone, and hence are more difficult than the latter to transfer from 
the nursery to the orchard. When the young Macadamia trees 
are dug up from the field nursery the soil tends to fall easily from 
their roots. Such trees, although carefully transplanted, may fail 
to survive. Pot -grown trees can be removed from the containers 
with little disturbance to the root system and transplanted without 
loss. 
In the Hawaiian Islands the Macadamia tree may be set in the 
orchard during any month, but preferably it should be set in the 
fall or the winter, when the temperature is lower and moisture 
abundant. There are several ways of arranging orchard trees in 
rows. The most important of these are the square, triangle, hexag- 
onal, and quincunx. These methods are described in popular hor- 
ticultural books. The first is the more commonly used in orchard 
work and is quite satisfactory for the Macadamia. The trees are 
set in rows 30 by 30 feet each way on the square. (Fig. 8.) This 
will permit the growing of 48 trees to the acre. The trees do best 
when they are set while small, either during the latter part of their 
first year, or during the first half of the second year. The holes for 
planting should be at least 2 feet across and about as deep. Sur- 
face soil containing some coarse sand and enriched with well-decom- 
posed barnyard manure should be placed in the bottom of the holes 
before the trees are set. A similar mixture should be pressed in 
firmly about the ball of earth on the roots so that the natural ground 
line of the tree will be 2 or 3 inches lower than the natural surface 
of the orchard to form a shallow basin about each tree to hold water 
