Walter Hill and Ferdinand Von Mueller, botanists, became fascinated with the trees in the mid-1800s(2), who created a new genus to put them in 1858 and named them after "John Macadam, MD., secretary of the Philosophical Institute of Victoria."(1) The first macadamia plantation only came out the 1880s(1,2), in the northern portion of New South Wales, Australia. Hawaii started planting the trees as windbreaks in 1882(1). It was only with the arrival of "successful grafting techniques and the introduction of mechanical processing that commercial production of the tough nut became feasible. Macadamia enthusiast Norm Gerber pioneered the grafting techniques"(2).
Encouragement to grow macadamias in Hawaii came about in 1910 by the Hawaiian Agricultural Experiment Station. The University of Hawaii worked on commercial development in the 1930s, yet large exportation of the nuts from Hawaii wouldn't come till after World War 2(1).
References:
1. "History of macadamia nut." Food History. Food History. 25 Sept. 2017. Web. 12 Jun. 2021. https://www.world-foodhistory.com/2017/09/history-of-macadamia-nut.html.
2. "History of the Macadamia." Australian Macadamias. Australian Macadamia Society. Web. 12 Jun. 2021. https://www.australian-macadamias.org/consumer/our-story/history-of-the-macadamia.