Holy cow you should have seen the rabbit damage on some of the small Tulip Poplar saplings on a few places we rabbit hunt. When we had that blizzard of 2010 the cuttings were 30-36" high on the trees b/c we had 28" of snow that lasted for 3 weeks (not the norm here in VA)!
Attached are 2 photos showing how deep the wound was on a SWO tree that was girdled around the entire tree. The second photo shows the tree after a complete recovery over 2 years later. I cut a piece of white coil stock large enough to wrap completely around the tree and secured it with a piece of copper wire for the summer and early fall in order to prevent insects from depositing oak wilt materials. After a little over 8 months, I removed the coil stock and let the tree heal itself.
Why did I suggest Bone Crusher might want to cover the wound? Simple, there are several pests that can attack apple trees and a new wound - discovered by BC in the spring - might provide an easy entry point for pests - during the warm spring and summer months - that frequently are found at lower levels of apple trees.
In addition to a number of insects that can transfer harmful "spores" for infection to apple trees - using wounds as entry points- there are pests that must be considered.
APPLE TREE PESTS http://treefruit.wsu.edu/crop-protection/opm/leafrollers/
See site for photos ..... Leafrollers (Omnivorous leafroller, Redbanded leafroller, etc) Platynota stultana Argyrotaenia velutinana
Redbanded leafroller on apple leaf omnivorous leafroller (Platynota stultana)
Leaves of plant rolled and tied together with silk webbing; feeding damage to rolled leaves; defoliation of plant; silk webbing may also be present on fruits and fruits may have substantial scarring from feeding damage; larvae wriggle vigorously when disturbed and may drop from plant on a silken thread. Comments Adult insect is a moth which can fly over several miles to find suitable hosts.
Management …Monitor plants regularly for signs of infestation; remove weeds from plant bases as they can act as hosts for leafrollers; Bacillus thuringiensis or Entrust SC may be applied to control insects on organically grown plants; apply sprays carefully to ensure that treatment reaches inside rolled leaves.
Both pandemis and obliquebanded leafrollers have two generations a year, whereas the fruittree leafroller and European leafroller only have one generation. Pandemis and obliquebanded leafrollers overwinter as second or third instar larvae within a silken case known as a hibernaculum. Hibernacula are found in protected parts of the scaffold limbs, such as pruning scars or small crevices in the bark.
Roundheaded apple tree borer (Saperda candida) adult
Damaged tree Roundheaded apple tree borer Saperda candida
Borer holes at base of tree
Larvae Roundheaded apple tree borer (Saperda candida) adult
The presence of bore holes at the base of tree which are covered by pigtail-shaped frass and/or darkened areas in the bark due to sap flow are the proof of insect infestation. The young may kill by one or two larvae infestation. The older trees show drying and break off near the base.
The insect is quite common in US and Canada. The host range of this insect is apple, pear, quince, mountain-ash, hawthorn and serviceberry.
Management Use of trunk wraps to avoid insect attack. Removing and killing of larvae from the tunnel if possible. Application of suitable insecticide.
Obviously, it would be of potential benefit for BC to apply an insecticide; however, if it were me, I'd also cover the wound until colder weather arrives and problematic insects are less prevalent. As I said, I used coil stock; however, rocks(?), buble gum, and even commercial wound dressings (petroleum based products that bugs are not likely to attempt to chew through) couldf be beneficial for a short period of time.
Purdue's discussion was largely in the realm of pruning; however, they did note ... "There may be some benefit for wound treatment with certain diseases such as Oak Wilt with a pesticide application to the wound."
Other Govt. orgs are less empathic ...
If construction activity, tree removal, or pruning is unavoidable, or if storms injure oak trees during the critical period, the wounds should be treated with a commercial tree paint or wound dressing. If whole trees are removed during the critical period, the stumps should also be treated with tree paint. It is very important that the fresh wounds be treated immediately because the insects that carry spores of the pathogen are often attracted to these wounds within a very short time.
If pruning is necessary, or if wounds occur on oak trees during the critical infection period, apply tree wound dressings or paints as soon as possible to prevent transmission of oakwilt.
Michigan State Univ .... says ...https://www.canr.msu.edu/outreach/index "Should wounds occur during this period, they should be immediately coated with a latex-based paint to exclude the beetles. This is one of the few cases where tree paint is recommended. Generally, tree wounds should not be painted."
I don't even need animals or bugs to screw up a tree; happens when you have too many and forget a ribbon that was used to hold a tree up straight. Will try some delicate surgery next week to attempt to correct; otherwise, we'll see if it can heal itself. May have to cut and start new central leader. Tree is only 2.5 yr old; however, it's a Kindred Spirit - (hybrid SWO X English col oak) planted in a wet area that appears to spark growth. leader.