Vigor  - Vigor is the capacity to resist strain; a genetic factor, a potential force against any threats to survive.  We can not change this.  Vigor is the capacity to survive when threatened.  Vigor is the capacity to resist strain.   Another story - Vigor is the genetic capacity of an organism to resist strain.  Vitality is the ability of an organism to grow under the conditions in which it finds itself.  Capacity is the potential; what an organism has.  Ability is the dynamic; what an organism does with what it has.  Vigor can be measured by applying a known stimulus, and then measuring the response.  You do not know how vigorous an organism is until you apply a stimulus that threatens its survival.  Vigor is the capacity to survive under increasing stimulae that threaten survival.  Vigor can not be increased, it is part of the genetic program.  Trees that compartmentalize more effectively than others are more vigorous than those that compartmentalize poorly.  When some abiotic agent stresses trees, the trees that stay alive are those that are more vigorous.  Vitality is another subject.  Vitality means to grow, to reproduce, to adapt to the surroundings.  Vitality is a dynamic condition.  A tree could be very low in vigor, yet high in vitality, and the converse could also occur.  Much can be done to increase vitality of a tree; “proper” fertilization (See “Fertilizers”), soil aeration, “properly” watering.  And, again, it is not so important to argue over words, as it is to know that there are 2 different processes involved here, and they do overlap.  However, if we want more vigor, we go to genetics; if we want more vitality, we go to improved cultural practices.

In other words:  Vigor is a genetic feature; a capacity. If a tree has the very best genetic code, yet is mistreated, it will suffer, and maybe die. Vitality is a condition resulting from the type of treatments and the ability of the tree to survive with high amounts of stored energy.  If a tree has a weak code, but receives excellent care, it will do much better than a tree that has a great code, but is mistreated and has a very small amount of energy reserves.  Arborist can help or hurt trees.  No one can alter the vigor of a tree unless they are breeders or geneticists working on better material for different sites and uses.  Arborists work with vitality, not other features.  You can plant a tree with high vigor on a rock, or mistreat it, and it will not grow as well as the tree with low vigor code, yet receives excellent care.  SHIGO

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