jueves, 31 de octubre de 2013

Seal or not? Compartmentalization Theory

Seal or not the wounds of trees? It seems like a difficult question to answer but it should not be. After reading this article draw your own conclusions.

One of the most controversial concepts and doubts assail among bonsai enthusiasts is the use of salves, pastes and other paints and potions called "healing". But are they necessary? If it sold for such use will not it?

This item comes from a controversy that I found on the net in relation to an article by Walter Pall .Walter is characterized by being quite critical of those practices that are not in their line of work. And in most cases not without reason. Quote in his article the Compartmentalization Theory of  Dr. Shigo. It is possible that after reading to Walter you find somewhat confusing if you're not too put in plant physiology and is why me encourage to enlighten you a little. As to whether to seal or not to seal a tree wound first we must know how it works, right?

If any of us do a wound,  our body will heal quickly and within weeks regenerating skin will be gone. If the wound is larger we will have to heal and disinfect and even cap on until the bleeding stops. But after the days our body will work diligently to fix the mess.

But the trees works like us? Obviously not, yet we insist on applying ointments and balms to heal their wounds (even tourniquets I have seen!)

It seems incredible, but it was not until 1985 (so late to prove something so obvious) when the American Pathologist Alex Shigo
presented in society in the Scientific American magazine his "Theory of compartmentalization"

Dr. Shigo (1930-2006) is considered the "father of modern arboriculture." Really quite a character with a great philosophy of life. His are some famous quotes like "If the study of something requires a lot of effort and work, probably has not been thoroughly studied." And is that Dr. Shigo was criticized by his fellow professors that frowned on the main tool of a teacher outside a chainsaw. In 1959 he was hired by the U.S. Forest Service to investigate the causes of the decay of trees. Chainsaw in hand gutted hundreds of trees which helped to draw their own conclusions and advance his theory.

Another great phrase of his: "A myth begins when people use terms that can not define"

The animals are cured, trees compartmentalize

If any mammal do a big cut on a limb, probably have to be amputated quickly so that no "cangrene" and spread infection throughout the body. Instead we like to stop at bonsai jin and shari pretty dead wood to increase the drama. Parties are dead and the tree does not change "gangrene".

Could it be that the trees have to take care differently than mammals?
But back to the theory of Dr. Shigo. From now on we will call as CODIT thanks to the mania of American compact any scientific word more than 7 syllables.

In his career, Dr. Shigo compiled more than 100 erroneous myths about arboriculture. And one of those myths was the one who said you had to cover pruning cuts to prevent rot. For centuries (and today's who insists, and yet the Earth is round) is practiced painting or stopping cuts with waterproof substances and even pesticides to protect wounds exposed to attack by pathogens, insects and fungi.

But Dr. Shigo showed that a tree is able to isolate the wound rot to not invade living tissue. The paste may serve more for a protection to the pathogen, creating an increase in temperature and humidity in the area, that for a tree prevention.
A tree may appear healthy and still have so many infections. These are separated by barriers, isolating and to control pollution.
Here without too much technical detail what those barriers described in Dr. Shigo in CODIT theory.

The barrier 1 has immediate action. Cells phloem, xylem and cambium are broken and produce compounds which warn the location of the wound on the shaft and simultaneously resist microbial attack. Protects the wound spread vertically. That is, up and down the shaft.

Barrier 2
Resists the spread inward. The barrier starts from the first intact phloem ring closest to the wound. (in the picture to the right in dark blue)

Barrier 3
Resist the radial spread to the sides. Is produced from the medullary rays. In light green image.
Barrier 4
Generation of new cells forming a callus or scar. In the picture in blue.

Some graphic examples of this barrier 4. In bonsai known as "lip healing":

In the above picture you can see the marks of an old infection compartmentalized. He's just a brushing chart on the theory of share ...... (CODIT in short). We invite you to read the complete article by Dr. Shigo as well as learn more about their research. It's really worth.

Let's see how we should act in bonsai
The most important thing is to always work with the right tools. We must always get clean cuts to ensure rapid healing.
In the work of dead wood, the first and basic thing to do is make accurate tree vein alive. And it is a task that we do every season if not done proper healing. What does this mean to you? If not clearly delimited with a wound clean and clear where the boundary between the living and the dead is possible that the tree is weakened and increasingly will have fewer living part. "In order to heal you have to hurt again, but better."

But you have to put in the wound and in the pruning paints, balms or fillings? The answer is NO. With few exceptions.

Results of a small experiment. The wound on the left was sealed with healing balm and the right does not. Both have healed and change in one of them have an ugly gray mark with the product.

In the image below we can see a great healing callus pasta but remains five years after application.

When we can apply sealants?

Good sealing in malus healing unaided .

The following is an entirely personal opinion but I want to convey as a biologist , and especially on my experience as bonsaist .

Some species heal worse than others. Always depending on their stamina and health. Others tend to remove sap in the cut branches even to dry . Dr. Shigo among many studies found that there was a tough barrier at the junction of the branches to the trunk . So if a pathogen could enter through the initial injury , it could dry branch to the trunk but would find a strong barrier . In some species the removal of sap (sometimes without apparent reason ) is very common . Poplars , maples, bouganvillas , ... etc. . are examples. In these species but recommend sealing with easily removable products . Just our experience tell us when you need to remove the seal. It sometimes takes a few days. A very valid and cheaper option is the use clay or even Walter Pall , the milk fat . If you are using clay that is brightly colored and so removing it will not forget soon.
We also recommend after conducting large pruning cuts in times of great activity for the tree. In these cases you can produce a strong " bleeding " very shocking to us but not too serious . A temporary plug can be interesting.

We end this article with a new appointment of Dr. Shigo :

"If it is published it must be true ? Truth is transitory and evolving knowledge. Not everything that is in the books is correct , much less what is in the newspapers or on the internet . If we are not sure, seek help from an expert and if you still have recourse to the common sense "

By Sergio Martinez

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