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

Table 2. Minimum temperature regimes of areas in Hawaii, Australia, and California
Area Average minimum temperature °C (OF) Remarks
Hawaii
Kainaliu
Waiakea
Pahala
Kalopa
Hamakua
Mealani
Kamuela
December
13.9(57)
17.2(63)
17.2(63)
12.8(55)
12.8(55)
10.6(51 )
12.2(54)
January
14.4(58)
15.5(60)
17.8(64)
11.7(53)
I I.I(52)
8.3(47)
1l.! (52)
February
13.9(57)
15.8(60)
17.8(64)
11.8(53)
I l.!(52)
10.0(50)
11.7(53)
Excellent
"
"
Poor La bad
"
"
"
Australia
AlSLanville (Lismore)
Nambour
Bandaberg
Atherton Table Land
Bowen
Townsville
Ingham
Innisfal
Cairns
June
10.3(51 )
8.0(46)
11.9(53)
10.6(51 )
15.7(60)
14.2(58)
13.9(57)
15.8(60)
17.6(64)
July
9.2(49)
6.4(44)
10.3(51)
9.5(49)
15.0(59)
13.4(56)
13.0(56)
14.8(59)
17.0(63)
August
9.9(50)
7.2(45)
11.4(53)
10.4(51)
16.1(61)
14.4(58)
13.8(57)
15.0(59)
17.4(63)
September
11.7(52)
9.7(49)
13.9(57)
12.1(52)
18.2(65)
17.1 (63)
15.1(59)
16.5(62)
18.6(66)
Bad; too cold
"
"
"
Should be good
"
"
"
"
California December January February
Vista 1.7(35) 1.7(35) 2.2(36) Subtropical temperature
Escondido I.I(34) 3.9(39) 3.3(38) "
Examination of Table 2 and Nakata's raceme
count in Fig. 29 indicates that the temperature
regimes of Waiakea and Pahala, with their high
yield of 6000 pounds per acre, are closerto Nakata's
best treatment at 18°C. Kainaliu is slightly lower
in temperature than Waiakea or Pahala, but a
temperature reversal pattern obtained here results
in a dry flowering season with hardly any blossom
blight diseases, allowing nut set to be excellent.
On the other hand, Kalopa and Hamakua are at
Nakata's 12°C, and yields are about 2000 to 3000
pounds of nuts per acre. Whatever trees are
growing in the Mealani area are bearing very
sparsely; however, the tetraphyllas planted at
Kamuela are thriving.
The minimum temperature regimes of the
Australian areas now in macadamia production
(Table 2) are quite similar to, or lower than, those
obtained at Hamakua and Kamuela. In fact, the
temperatures from Alstonville to the Atherton
Table Land more closely resemble those obtained
at Mealani, which is cold and wet, and
where the integrifolias do not yield.
The minimum temperature is probably the
main cause of the poor yield-both at the higher
elevations in Hawaii and in the Australia macadamIa
areas. These areas in Australia yield only
28
about half of tha t obtained in the tropical zones in
Hawaii. The suggestion is made here that macadamia
should not be planted much beyond 1500
feet in elevation in Hawaii. Perhaps in Australia
the macadamia nuts would do better on the lowlands
between Bowen and Cairns, which have
temperatures comparable to Hawaii's tropics.
California, on the other hand, gave up on the
integrifolia a long time ago, and plants only the
tetraphyllas. Allen (1), working on photosynthesis
and heat stress of tropical plants in South Africa,
suggested the temperature range between 16° and
25°C as best for photosynthesis in macadamia. In a
gross sense, his findings support our belief that
12°C during the flowering season may be too cold.
These temperature analyses and yield performances
from the fields in Hawaii seem to indicate
that Nakata's growth room findings are real and
reliable. Until better records are experimentally
produced, the minimum temperature regime concept
presented here should be used to help in the
production of macadamia nuts.
Categorically, the macadamia nut tree can be
economically grown atelevations in Hawaii where
pineapple, guava, coffee, papaya, mango, and
banana are profitably grown. Except for a few
areas with definite southern exposure, most of the