The Macadamia Nut In Hawaii

                          by John F. Cross

To most of you orchard men of the Northwest, the Macadamia (pronounced Mac-ah-dame-e-ah) nut is completely foreign, not only the tastes of this delectable nut but the appearance of the tree as well. So, it may be interesting to touch on the historical background of the Macadamia and how it was introduced to Hawaii.

The tree is indigenous to Queensland and New South Wales, Australia. The nut was named after Dr. J. Macadam, President of the Victoria Philosophical Society, who was supposedly the first person to find the nut edible. Incidentally, Australia grows only a limited commercial acreage.

It is generally considered that the first trees were introduced between 1888 and 1892 by Mr. R. A. Jordan who collected the seed and sent them to his brother, Mr. E. W. Jordan, in Honolulu. The first ones planted did so well that the trees became popular as ornamentals and in some cases were used for reforestation purposes. The first commercial planting of macadamia nuts in Hawaii was in 1922, when a stock company was formed and sizeable orchards were set out on the islands of Oahu and Hawaii.

There are two types of macadamia nuts, the smooth shell Macadamia integrifolia, and the rough shell Macadamia tetraphylla. The former is the commercial variety.

This evergreen tree grows fairly rapidly with heavy, dark green foliage, and bears its small white flowers on long racemes. As many as 300-400 flowers can be seen on one raceme; however, only from I to 25 nuts will be matured. Three or four-leafs grow in a whorl, are oblong, and vary in length from 5 inches to about 10 inches. The leaves are serrated very much like the holly leaf. The nut or seed is enclosed in a fibrous husk, and the nut size varies from 3/4 to 11/2 inches in diameter, spherical in shape. Sometimes two hemispherical nuts are found inside the extremely hard-to-crack-shell. The kernel is of delicious flavor, resembling a cross between the hazelnut and the Brazil nut; however, some say it tastes more like a hazelnut and an almond.

The kernels are cooked in oil and salted, which results in a better-flavored nut. They contain between 70-75 percent fat, and are a good source of vitamin B-l, calcium, phosphorus and iron, which makes the macadamia a concentrated food (13 gm. equals I00 calories).

In 1935, commercial plantings in Hawaii were estimated at 800 acres containing about 60,000 trees. By 1948 the area had increased to 1,200 acres with production of 740,000 pounds of unshelled nuts that year.

Land not in sugar, pineapple or cattle is difficult to find in Hawaii. Castle & Cooke, Limited, a large business organization in the Territory of Hawaii who, along with others, recognized that there was an urgent need for diversification of island industries to spread the risk and provide new ways for the community to earn a living, finally found and purchased 1,000 acres of land at Keaau on the Big Island of Hawaii from W. H. Shipman, Limited, for the purpose of large scale Macadamia nut plantings. A further purchase of 2,000 acres adjoining the first 1,000 was made in 1951 for the same purpose.

The site of Keaau Orchard is a prehistoric lava flow of the clinker type, which before clearing was a dense tropical rain forest of Metrosideros collina, Psidium Guaiava, Cibotium, Pandanus and other trees and shrubs. Clearing is accomplished by bulldozer, with all vegetation except the Metrosideros (ohia tree) broken up and turned under to rot, thereby adding humus to the rocks. The latter, a stonehard wood, is burned.

As of September 1954 approximately 935 acres of this former jungle land had been planted with over 65,000 macadamia nut trees. We expect to have 1,000 acres planted with 70,000 trees by October 1955.

All the trees planted so far, and those to be planted, are grafted trees of 7 varieties of Macadamia var. integrifolia, the smooth shell variety. The type graft used is called "side wedge". Rootstock is raised in seedling beds, and the scions are grafted at a seedling age of about 12 months. Percentage of takes varies from 90 to 95. The varieties being used are seedlings selected over a period of years by the Agricultural Experiment Station of the University of Hawaii. These grafted trees come into bearing at an age of 5 years, and come into full bearing when they are about 15 years of age. The average yield of a mature tree varies from 100 to 140 pounds of in shell nuts. The nuts mature on the tree and drop naturally to the ground. A major problem here develops because the flowering and hence the harvest period can be over
a six month period.

At the present time there are approximately 15 commercial macadamia orchards in the Hawaiian Islands. The total acreage of planted trees is about 2,400. While Hawaii's commercial output of nuts was just over one million pounds last year, this figure should be double when Keaau Orchard reaches peak production.

While Hawaii's subtropical climate is quite suitable for the growth of macadamias, the trees are demanding in their needs; they require 40 to 100 inches of rainfall a year, with good drainage (they will not stand "wet
feet"). It is necessary that they be protected from strong winds, which have a tendency to split and uproot them. Judicial pruning to guard against "V" notches and to produce the maximum of bearing surface is an absolute necessity during the early years of growth.

We are harvesting our first very small crop this year, 1954, but the harvesting operation is still an unsolved problem, because the rocky terrain under the trees makes mechanical devices difficult to operate. Experiments are underway to improve nut-cracking machines or find a cracker that will efficiently and economically crack the Macadamia. (The Macadamia has one of the hardest shells in the world). Marketing problems are being surveyed and evaluated, and a processing pilot plant was built this spring after intensive processing research was made by food scientists in California.

Hawaiian growers have spent millions of dollars in research in growing sugar and pineapple, with the result that production records in the islands have far outstripped other producing areas in the world. While truly large-scale production of macadamia nuts is still in the future, there is confidence in its success, which should result from continued research.