I got the chance to visit a farm recently on Molokai.  Amongst other things, they grow macadamia trees, Macadamia integrifolia.  They had about fifty trees on their farm that had been there since the 1920s. Farmer Purdy explained that macadamia nuts start off as pale, slender, bottle-brush shaped flower clusters.  The flower cluster is pollinated by bees and later forms small green nuts.  The nuts grow and when they are ripe, they fall to the ground.  The family gathers the nuts daily from the orchard floor.  Harvest is essentially year round.  The family then husks them, dries them, cracks them and roasts them without any preservatives. 

The farmer said that because his is a small multi-crop farm, he has not found the need for any insecticides.  The only thing he spreads around the trees is ashes from the burned leaves that he rakes up daily. He stressed that because the crop is picked up from the ground, the orchard must be kept very clean.  It was so unique to look up into the tree and see every stage of the nuts' life cycle all growing at the same time. And cool to think of a year round harvest.