After cutting tree limbs
My dad used to put a black tar on the exposed part of a cut limb from a tree. But I thought I learned in later years that it was not healthy for the tree. Can you verify? Is there anything to place on the exposed part of tree to protect it from outside elements or insects, like petroleum jelly?
Thank you for your question.
It is tempting to apply a wound dressing to a pruning cut. This age-old practice, however, has been shown by several research scientists to be of no benefit to the tree and can even harbor disease organisms.
Wound dressings are sometimes desirable for aesthetics, to hide or camouflage the exposed wound. If this is the case, use the type of material in aerosol cans available at garden centers. Apply a thin coat. It should barely coat the wound, changing its color but not forming a thick, black film.