Succession  - Microbial succession is the orderly sequence of many different microorganisms infecting a wound.  The wood at the margins of the interaction between tree and pathogen is changed.  The pioneer pathogen must always interact with the tree and its defense system on one side and with other potential pathogens that are competing for the new energy and space on the other side.  As the wood changes, and as the microenvironment and the ambient environment change, conditions may favor the spread of another pathogen within the compartmentalized column.  The pioneer pathogen may be able to survive very close to the reaction zone, and cause the zone to slowly retreat, but the same pathogen may not be able to survive in the wood that is distant, or proximal to the reaction zone.  The 2nd law of thermodynamics comes into play again.  The energy stored in the wood and the energy stored in the organisms that died in the wood is passed on to others until all the energy is used.  There are short-term annual successions, and long- term successions.  Some organisms can only survive when temperatures are high, and some when temperatures are low.  Microorganisms are not altruistic.  They do not die so another organism can live.  Each organism competes with others to maintain a niche for as long as possible.  Successions in trees do not mean that bacteria and non-decay causing fungi always infect first.  No!  Succession means many species infecting in an orderly manner.  No doubt, the decay-causing fungi are just as active on the fresh wound surface as other organisms.  They may also be the first to invade.  Some Hymenomycetes can only survive if they are the first to invade.  The fungus that causes the disease called silver leaf is an example.  Most fungi in the (old) genus Stereum are pioneers.  In some cases, the pioneer that is a Hymenomycete incites the tree to respond so rapidly that the organism that started the defense response cannot spread into the reaction zone.  An organism that can survive in the reaction zone, or even digest it, will then become the new pioneer. Successions give the tree time to generate new cells in new positions.  Succession gives the microorganisms an opportunity to survive.  Most microorganisms have very short- term reproductive cycles, so long-term time is not a factor for their survival.  Succession and compartmentalization make it possible for trees and microorganisms to survive.  Note: Successions of microorganisms lead to tooth decay.  Tooth decay is the most common human disease.  History:  “In the beginning there was Curiosity!  Some of the information in textbooks did not agree with what I was seeing in dissected trees.  Were the trees wrong?  Or, were the books wrong?  I had to satisfy my curiosity.  AUTOPSY MEANS TO SEE FOR YOUR SELF.  Thousands of trees were dissected.  Hundreds of thousands of isolations for microorganisms were made.  From this research came concepts of successions and compartmentalization.  
    Succession means an orderly sequence of microorganisms.  It does not mean that organism A is always first, followed by organism B, and so on. and so on.  In some cases the decay-causing fungi may be the pioneers (332) but most of the time, not all the time, bacteria and non decay-causing fungi are usually the pioneers (A). This is so because some of the microorganisms have the ability to alter, or actually digest, the antimicrobial substances in the reaction zone.  Where decay-causing fungi may act as pioneers, their presence may stimulate the tree to produce even stronger boundaries.  In this case, the pioneers may soon limit their own survival.  But, remember, in nature, somebody is always waiting for your energy and space. So it is with successions in trees.
    In other words.  Succession is a survival process for microorganisms.  They infect and spread through a substrate (wood after wounding) in an orderly way to optimize the energy in the substrate.  They utilize and transfer energy so that all organisms have equal opportunity for survival. 
    In other words.  Succession is a survival process.  Itís a survival process for trees and for microorganisms.  Here we are talking about micros.  They infect and spread through a substrate in a tree in an orderly way to optimize the energy and other conditions of that substrate.  But what this means is that if itís cold, the cold guys get in.  If itís warm, the warm guys get in.  If itís wet, the wet guys get in.  If itís dry, the dry guys get in.  But they optimize the conditions of the substrate.  In other words, where they can have space and an energy source.  And they all have equal opportunity for survival.  And they all belong to, in a sense, in a metaphorical sense, the good old boys club.  Because when they get in they have to fight off both sides.  They have to fight the organisms that are providing the substrate and they have to fight others on the other side so that their space is not taken.  One very very important part about succession you should know, is that if all else, you wonít forget Ė this is how compartmentalization started.  It did not start with the boundaries.  It started with hundreds of thousands of isolations.

Dictionary MAIN PAGE
Text & Graphics Copyright © 2007 Keslick & Son Modern Arboriculture
Please report web site problems, comments and words of interest, not found.