Pecan and pistachio
trees are considered temperate climate trees. Therefore, in Hawaii and other
tropical areas, optimal production would, in all likelihood, not be possible.
The trees will grow, but how much fruit will they yield? Pecans require 250 chilling hours (number of hours below 45 degrees
Fahrenheit) before they will produce a good crop. This chill factor will not be
met in Hawaii, yet trees will still yield some fruit. Although growing pecans at a higher elevation
will give them a better chance to fruit, they also require a hot summer climate
to mature the nut. In addition, two
different varieties must be planted together for good pollination and better
production.
A mature
pecan tree is growing at the Kainaliu Experimental Station on the west side of
the Big Island. Elevation is approximately 1,300 feet. The tree is sporadically deciduous – loses its
leaves, and over the years it has produced pecans. The variety is unknown.
There is
also a Hall's Hardy Pecan growing at 1,200 feet near Pahoa on the Big Island.
It has produced some nuts, but it is still young. Rainfall is 200 inches
annually.
Pistachio trees need 800 chilling hours and
require long, hot dry summers; male and female trees must be planted. Obviously, pistachios
will not produce well in the tropics.
A large
portion of the world’s Brazil nuts
comes from Brazil and Bolivia. The trees should
grow in Hawaii, yet they may not yield good crops. The flowers can only be
entered and pollinated by large-bodied bees with enough strength to pry open
flowers in order to get to the nectar. It is unknown whether there are
adequate large-bodied bee populations in Hawaii.
