NOTHING! You see when a tree is cut properly (unlike the picture of this cut limb), the tree “compartmentalizes” the injury at the cut location. Trees can resist the spread of bacteria and/or microorganisms at the cut location naturally….some trees faster than others but it will happen. The “compartmentalization” process helps stop the decay of the tree from spreading.
In fact, dressing the wounds could indeed cause an infection or further damage to take place in the tree, causing further decay, and decay at a faster rate.
So, what do you do? As I said earlier, NOTHING. Let nature take its course. Do not paint the wound. The tree will heal naturally! And the million dollar question here is “Why is this a sample of what NOT to do”? Zoom in on the picture and send me your response. – Joe Yedowitz, CLT