It seems that if energy and water are stored, and that elements are also essential for life, then there must be some way the tree stores elements.  It is difficult to conceive that growth and other element-requiring processes receive elements at the time they are required.  There must be a storage process for elements.

Trees are clusters of highly ordered systems; a conglomerate.  Each system requires time, optimum conditions, and a ready supply of energy, water and elements.  Each process takes time. In temperate climates there is just not enough time during warm periods to have every process of every system conduct its activeties.
    Survival in living natural systems depends on the rate of adjustment and adaptation to abiotic systems beyond the control of the biotic systems. Abiotic systems provide space, temperatures, elements, water and energy.  The positions on Earth where these factors exist are very different, yet life forms have developed in almost every conceivable place, including ocean vents, to boiling springs, to cavities within deep ice.
    It is not difficult to expect processes of some long-term systems optimizing places and conditions considered not the best for life.  Absorption of elements developed or adjusted to low temperatures.  This then extended the time for a larger cluster of systems to survive.  Trees have always been and still are the most massive, tallest, longest living organisms on Earth.  To be such superior survivors without the benefits of movement, the tree systems adapted and adjusted to every possible condition present over a period of one solar year.

    Mycorrhizae are organs made up of fungus and tree tissues.  The organs facilitate the absorption of water and elements essential for healthy growth.   Trees have many redundancies, some for short-term conditions and some for long-term conditions.  Root hairs are finger-like extensions of single epidermal cells that contain very little lignin in their walls.  The cell walls of the epidermis do have cellulose, which is not the best of boundaries or membranes for absorption of water and elements.  Root hairs are usually ephemeral.  They grow as new roots grow and they go or die as woody roots begin to form a bark that contains suberin.  Their numbers are usually so great that even if they are poor absorbing structures, they still absorb some water and elements.
    Mycorrhizae present a system of synergy.  The fungi receive more and the tree receives more with this association.  Mycorrhizae live for long periods; a year or more. (Note forms that bud.) |
    A mycorrhiza starts when a hypha from a germinating spore infects a newly forming non-woody root.  When some fungi infect a root, they control the further development of that root.  Some fungi penetrate the root and hyphae spread far beyond the root.  It is not uncommon to see some mycorrhizae with hyphae completely wound about the organ.  Root hairs do exist on some mycorrhizae.
    The question quickly arises about how fungi can exist in roots in soil under water.   To make sure the roots were from neighboring trees, samples were collected from streams where only one tree species was growing.  Large woody roots with smaller masses of roots were dug.  The mycorrhizae were on the tree roots, mostly Acer rubrum and Ulmus americana.  
    The fungi in roots under water appeared typical for species close to Glomus - a member of the Zygomycetes.  Chlamydospores of several types were abundant from the winter samples.  (The organisms in the roots could be oomycetes, which are close to water molds.  If this can be shown, then the organisms would be better classified as endophytes.  There is so much yet to be learned.)

    Membranes are nature's discriminators.  Membranes keep things in that should stay in and keep things out that should stay out.  When membranes lose their ability to discriminate, the cell will die.  When many cells die, the organism will die.
    Membranes and bonds are extremely important.  Bonds hold matter in place and the bonded matter is further kept in place by some membrane.  The basic unit of life - the cells - speaks to this point.
    Plant cells have vacuoles and turgor pressure.  Animal cells have neither.  Plant cells have a continuous symplast made possible by plasmodesmata.  Animal cells have another means for intercellular communication called channels.
    Root hairs have cellulose as the major substance in their outer membrane.  Fungi have chitin, which contains nitrogen, in their outer membrane.  Chitin must have unique characteristics for absorption.  Fungi have hyphae that grow through a substrate.  Energy-yielding substances, water, essential elements, and vitamins must be absorbed through the chitin-rich membrane of the hyphae.
    The connection of fungi with trees optimizes two absorbing systems - cellulose in root hairs, and chitin-rich substances in hyphae.  Mycorrhizae with root hairs have both systems.

    What determines what stays in and what comes in?  And what drives this process of absorption?  No system can start itself.    
    Respiration starts the absorption process and once started, concentration gradients and the Le Chatelier principle keep it going.
    Trees are multiple systems operating in states of dynamic equilibrium. There is the appearance of balance or the static state while really many processes are moving at equal rates in opposite directions.
Many tree processes can be explained by the Le Chatelier principle. Natural processes move toward a state of balance, but when they do reach balance, they die.
    Yet, as one part decreases or leaves the equation, the process moves in that direction,  again in an "attempt" to establish balance.
    An understanding of dynamic equilibrium and the Le Chatelier principle are essential to an understanding of not only absorption, but many other tree processes.  Remember, balance means no movement; death!

Compounds of carbon, oxygen, hydrogen, nitrogen, sulfur and phosphorus make up about 98 percent of the mass of trees.  Carbon, oxygen and hydrogen come from water and carbon dioxide; but where do the others come from and how do they get in?
    The elements are absorbed as ions.  Ions are molecules, or elements, that have a positive or negative charge.  Like charges repel, and unlike charges attract.  Ions move.
    Nitrogen enters as nitrate anion or as ammonium cation.  Phosphorus and sulfur enter as molecules bonded with oxygen as anions.  Each element enters in its pure state.  Ions of sulfur, phosphorus and oxygen are big and heavy.  In ways I do not understand, the fungi with chitin in their hyphal walls facilitate the absorption of these ions.  The absorption of phosphorus by mycorrhizae is one of their most important functions.
    Nitrate ion has a molecular weight of 62.  Ammonium ion weighs 18.  Now back to respiration.  Energy from glucose from stored starch in living root parenchyma cells is made available for tree processes by respiration.  Respiration is an energy - releasing process.  Products of the process are carbon dioxide and water.  When some carbon dioxide dissolves in water, carbonic acid forms.  The acid dissociates to form hydrogen ions that bond with water to form hydronium cations and bicarbonate anions.  Hydronium weighs 19 and bicarbonate weighs 61.  When you add 19 and 61, 80 is the sum.  When you add the weights of nitrate and ammonium, you also get 80!  On the tree side of the rhizoplane, the two ions weigh 80, and on the rhizosphere soil side, the ammonium of 18 and nitrate of 62 again weigh 80.  Coincidence?  I wonder.
    Back to cold soil and cold water under ice.  First, water.  Cold water contains more oxygen than warm water.  Oxygen is a requirement for respiration!
   
Clusters of ice crystals form in minute cavities.  Soil does not freeze, but the water in soil freezes.

MYCORRHIZAE IN COLD SOIL

    In soil below 0 degrees Celsius, clusters of ice crystals form in minute cavities.  In a sense, soil does not freeze, but the water in soil freezes.  That is not as important as the fact that cold soil will have many ice clusters.  I believe the ice clusters in soil act in a way similar to the sheets of ice over water.
    Plants that are not cold hardy die from dehydration because water moves out of the cell, because water moves from high concentrations to lower concentrations.  As ice forms in soil, liquid water moves toward the ice clusters.  The abiotic cold factor then acts as a trigger for molecules to move.  It is fascinating to know that light heat from the sun triggers processes that make life possible - photosynthesis.  And, low temperatures also trigger life processes.
    As water moves toward ice clusters, air with oxygen fills the cavities. Many living organisms - bacteria, fungi, mites, thrips, nematodes, enchytride worms, amoebae -live in the oxygen-rich cavities.  And, roots live there also.  Abiotic factors trigger biotic processes!
    The rhizoplane is the boundary between soil and living roots and hyphae.  The mycorrhizae serve both tree and fungus.  In roots in soil under water, I believe the endomycorrhizae benefit from the ready supply of carbon from the tree.  In ectomycorrhizae, I believe the fungi and tree benefit from absorption through a chitin-rich boundary.  I believe also that hyphae that grow out from mycorrhizae obtain some carbon from decomposing wood and leaves.
    Trees, as all living things, pay taxes.  Taxes are paid in the sense of exudates that contain carbon.  Many soil organisms benefit from the "taxes" and in return the organisms make elements available for the trees.  The words of Galileo come to mind as he was faced by his inquisitors.  Galileo said God wrote two books - Nature and Scriptures.  The problem, he said, was that few people have ever read or know about the book of Nature, and until Book 1 is understood, Book 2 will never be understood.  They did not understand what he said.  They issued his sentence!  (I am now working on Book 1.)
    Natural systems have developed in ways that benefit high-quality survival.  Systems in tropical climates are different from systems in temperate climates. 
    Back to rhizoplanes and the 80, 80 idea.  Respiration and the Le Chatelier principle work to keep the processes moving. The natural "attempt" for balance keeps getting disrupted as one part of a two-part system keeps moving to a decreasing state.  For example, to move or be absorbed into a root, the molecule must be in a soluble ionic state.  This state is soluble in water also, and as water moves in soil, the ions move along with the water away from the target living system. To say it another way, the same ions essential for life also move "downstream" to the groundwater or on to the ocean, where new and different life forms exist.  Indeed, the natural systems function to maintain life and non-life, and these processes go on, and will go on, without the intervention of humans.  This is what Book One is all about.

"Always" is what I believe in.  Where does a circle start?  I believe that philosophy is a mental trip around a circle.  Always.
    Life forms and abiotic forms move toward balance.  When balance is reached, the nature of the form changes; death.  When abiotic forms become so highly ordered, we call the resulting form "living."  When living forms become balanced, we call the resulting form "dead."
    So long as movement is ordered, life goes on.  Dynamic equilibrium gives nonmoving forms, such as trees, the appearance of balance, while actually many systems are moving.
    Nature is a super, multiple system made up of what we call living and nonliving forms.  Forces external to Earth - the sun - initiate processes of life and death.
    When these powerful forces begin to be recognized, then many parts will come together.
    In the end Modem Arboriculture will come, albeit slowly, mainly because old arboriculture is accepted by many people and organizations as it assures economic gains.  A new train is coming.  It is filled with students who have different ideas and values for life.  This train includes the quest for solutions that can only come from biology and Book 1, chemistry.
    The train is called Modem Arboriculture.  It runs on the energy of connections.
    The lack of knowledge of tree biology has been, and still is, the major problem for trees and tree workers worldwide!  Learn about trees.  Connect with nature.  Touch trees.