Adair, this is exactly the kind of stuff I'm talking about. There is a common scientific concept that sealing pruning cuts disrupts the compartmentalization and proper healing of the wound leaving the tree open to infection. This might be plausible in theory, however in practice you, me and countless others have found that, in general, wounds heal more quickly and thoroughly if the are cleaned and sealed from water and air.
This is the difference between theory and practice, between experience and concepts. This example alone demonstrates the author of the above book is relying on certain contemporary hearsay more than practical experience. If you want to learn about a subject, consult someone who has lived and breathed it for most of there lives.
I agree.
I have Zelkova that I purchased that has a 4 inch trunk. It had been chopped, and new branches started. It had been chopped several years prior to me purchasing it.
No cut paste had been used.
The chop on the top was beginning to callous over, at least on one side. The other side experienced die back. The bark was still there, but it was dead for about two inches below the chop. The heartwood had opened up, small cracks allowed water to get in, and it was beginning to be easily broken.
Now anyone with any experience with Zelkova knows it's heartwood is extremely hard. It's great furniture wood. Very dense.
So, when I finally got around to working the tree, I went after the dead wood with a die grinder and a "Terrier bit" I bought from Graham Potter. The damaged wood was easy to remove, until I got down to the I damaged heartwood. That stuff is hard! The Terrier was able to carve it, but it's really dense wood. I protected it with cut paste. The putty kind.
From time to time, every 6 months or so, I remove the putty, and check on it, and it is callousing over. But, what's more, the putty is protecting the heartwood. It's not opening and splitting. It's staying solid. It's not going to rot like it did before when it was uncovered.
Now folks, I don't have to have a degree in Horticulture to determine that using cut paste is beneficial to this tree! If I had left that wound uncovered, it would eventually have resulted in a hollow trunk, which I did not want!
In a natural forest situation, the tree can mostly cover over wounds. But, what often occurs is interior rot sets in. You can't see it until you cut the tree down, but it's hollow inside. I just cleared 5 acres of oak forest to create pasture land. Many, many of the trees were hollow inside. Evidently red oak is more prone to this than white oak.
It's fine to have an open mind to learn new things. Just make sure those new things are relevant to your goals. Check the evidence to see if it applies to your situation.
The proof offered to me about how tree sealant was worthless was based upon a study of trees in a forest with the type of cuts we don't generally do, on species of trees we don't use for bonsai. One wound they evaluated was a "core sample", a hole drilled straight thru the tree. We might do something like that when thread grafting a maple, but there's no reason to do something like that to a pine. And the sealant they used was that black tar based paint. Not the same kind of stuff we use. I reject the results of that study because it is so vastly different than what we do with our bonsai.
I would take it with a grain of salt.
