I hope this is better. Again, I appriciate your time.
Microelements - There are 17 essential elements (3 + 14) for trees that we
know of. We break them down to two categories. Macroelements and
Microelements. Macroelements are the big guys - N+P+K which is Nitrogen,
Phosphorus and Potassium. Calcium, Sulfur and Magnesium are also
microelements. They are required for life in higher amounts. On a weight
basis, about 99% of most plants are made up of carbon, hydrogen, oxygen,
phosphorous, and sulfur.
Then we go to the group called microelements. They should not be called
minor elements. Indeed, when they are lacking, life stops. They are
needed in very low amounts. Some microelements are Copper, Chlorine, Boron,
Nickel, Molybdenum, Zinc, Iron, Manganese. Sodium [Na] and Cobalt [Co] may
also be required in very micro amounts. Cobalt may be essential for the
mycorrhizal fungi. Selenium is found in some desert plants. Nickel is
required by the bacteria that form galls on leguminous trees. The bacteria
fix nitrogen. Silicon may be required by some plants and animals. Some
soils are lacking in some essential elements. Boron [Bo] must be added to
grow pines in some areas of the world. A healthy tree depends on the
correct amounts of essential elements in the soil.
You should know just a little about what each one does. Just to be on the
safe side. Some of the above are required by the fungi and not so much by
the tree. See "Food." See "Essential Elements."