Ossijinn
I think that's why it doesn't work; in order to be effective, one would have to apply more than one coat- perhaps five or more- to fully make the surface NON-porous.
That was my thought, having seen painted wounds from arborists of the past. As I picked at the 'sealant' and inspected, the edges, near the callus usually were curled and peeling. I'm not sure how the stuff holds up to moisture, UV rays, freeze-thaw cycles and the movement of the callus.
Completely filling and creating an absolute seal is the basis for my thinking we can arrest decay. I don't feel that sealants of the past did this effectively. If there is the ability for air to enter into the wound site, I believe that success will not be possible. Here is my oxygen schpeel.
We've ascertained that fungus is an aerobic plant. It has no chlorophyll, like other plants, so it does not practice photosynthesis. It does not, therefore, take CO2 and the energy from sunlight and create carbohydrates, proteins and fat. It is very much the reverse.
Fungi, as a family, get their energy from the carbon source, cellulose, of which wood is mostly made. Certain fungi have even been shown to be able to feed on hydrocarbons as a carbon source, and are used industrially to detoxify contaminated spill sites. This fact, alone, forces me to question using tar as a wound sealant.
Anyway, the fungus also uptakes nitrogen in the food source to biofabricate the enzymes, which are the true work horses of the fungus. The fungus, with their powerful enzymes, degrade cellulose and as a waste product, produce carbon dioxide. This is essentially a fermentation reaction, though most of us have a view of fermentation quite different, but also involving a fungus called yeast. The reaction is quite the same, however. Carbohydrates are broken down, with carbon dioxide being one of the biochemical 'waste' products.
Here's where full, complete sealing 'SEEMS' to make sense. From a purely scientific standpoint, this is my hypothesis (educated guess).
Fungus is a consumer of oxygen, and a producer of carbon dioxide. If we were able to encapsulate the fungus inside the tree, effectively cutting off the free source of oxygen (ie Air) this would seem limiting to the expansion and growth of the fungal body. There may be some available oxygen within the wood, but the fungus, I feel, will consume it faster than it can be replenished. Also, carbon dioxide levels will rise as oxygen levels fall, and the seal would prevent escape of the carbon dioxide.
Fungal growth, in this hypothetical scenario, will be arrested by virtue of cutting off it's necessary raw material (oxygen), and essentially smothering it in its own waste product (carbon dioxide).
That's the scientific hip I'm shooting from. It makes sense, and is proven, but just not in a tree cavity. The obstacle to overcome in giving this a go would be to have a product that could create an absolute sealing barrier, one that would withstand large temperature fluctuations, ultraviolet radiation, rain and must also be non-toxic to the tree and callus. As well, it would have to be able to remain intact for 10, 20, 50 years. Lastly, it would have to be applied in a manner that disallowed any air exchange (no leaks).
Will it work? That is, as they say, the $64,000 question.
It's not your eyeballs. It's having 100 eyeballs and more. It's statistic analysis. It's determining if the improvements you're seeing are significant and if they're the result of the variable(s) you're testing.
