Dear "Urban Forester":
I have read many of Shigo's studies and am unfamiliar with some of the quotes that you noted ("picnics and parties under wound dressings" , "Heartrot and wound dressings are twins") and my thread addresses these concerns.
I urge you to take a look at the science that demonstrates the benefits of Tree Wound Dressings in the control of Oak Wilt, Stone Fruit Canker, and several other diseases that are spread by insects or airborne pathogens. There is no disputing the benefits, as I stated it is actually mandatory in some parts of the country at certain times of the year.
As we pointed out, proper pruning methods should always be used, including timing, sharp, clean tools, and correct cuts. However some pruning is done as a result of natural damage, construction, and simply lack of ability to prune at the optimal time of the year..
We do not dispute that mis-use of tree wound dressings can lead to the formation of "pockets" which can lead to the concerns raised by Shigo and others. Tree Wound Dressings should be applied in as thin a layer as possible while still achieving coverage. .When applied properly, these "pockets" or "courts of infection" WILL NOT FORM.
Tree Wound Dressings have also been shown in many studies to reduce dieback, this was even noted by Shigo.
As for protection from insects boring into the tree, Tree Wound Dressings may offer some protection, but in most cases if an insect wants to bore into a tree it will bore into the tree. This is the insects role in nature, a wounded or pruned area probably makes little difference.
If you would like a listing of studies you may contact me at:
[email protected]