In the past, economics have governed any crop production, whether of
trees, grains, fruits or vegetables; not nutrition and health. The
future in all likelihood will demand improved crops from the standpoint
of nutritional purposes as foods. It is gradually being realized that
the production of better crops can be brought about by greater
application of essential nutrients to soils or as nutritional sprays
direct to trees, and that such practices also reflect true economics.
The same principle should govern wood production.
According to our today's knowledge, there are at least nineteen elements
invariably essential to life, viz:
Primary: Hydrogen, carbon, nitrogen, oxygen, phosphorus.
Secondary: Calcium, magnesium, sodium, potassium, iron, sulphur,
chlorine.
Micro: Manganese, copper, boron, silicon, aluminum, fluorine, iodine.
Then there are another eighteen elements at least variably necessary to
life, viz:
(1) Variable Secondary Elements: Zinc, titanium, vanadium and bromine.
(2) Variable Micro-Elements: Lithium, rubidium, caesium, silver,
beryllium, strontium, cadmium, germanium, tin, lead, arsenic, chromium,
cobalt and nickel.