Pruning 60' decideous trees and a tree fungus.

[def]

Hi, I have recently pruned a couple of large trees in our yard. I recall our neighbor painting the cut piece on the tree to protect it from the elements. What kind of paint could I use? Is this necessary?

I had to trim one tree due as it was rotten and about to fall anyway. I noticed a fungus on it and wondered if this was related to the branch being rotten. Any thoughts?

Thanks

[Treedweller]

Painting tree wounds is a thing of the past, with a few exceptions. Trees have developed a system (known as CODIT, or Compartmentalization of Decay in Trees, if you want to read more) of minimizing the spread of decay after wounding. The first step is physical plugs in the exposed vascular tissues, then comes chemical barriers to the spread of decay, and then comes the exterior growth that closes over the outside of the wound over time. This exterior growth comes from the branch collar and is the strongest barrier of defense.

If proper cuts are made

retaining the collar, the tree will do fine without paint--in fact, paint can interfere with the tree's response and lead to a defect known as ram's horn (because the collar tissues spiral inward at the edges of the wound instead of growing over the outside of the branch).

If branch cuts are made flush to the trunk, removing this collar, the tree will never effectively heal the damage, and internal defects are likely regardless of painting. In this case, paint may be useful since the tree is not able to do what it should. A "wound sealer" or "pruning paint" (find it in any garden department or nursery) would be appropriate. This is not a cure-all--the damage has been done--but might help a little.

Another exception is when paint can help prevent spread of disease. Oaks and elms are subject to fungal infections, called oak wilt disease and Dutch Elm disease. If you have an oak in an oak wilt center or an elm in a DED center, painting may be a good idea. The type of paint isn't really important, since the goal is merely to change the way the cut smells to the insects that may transmit the disease. I suggest a latex (water-based) paint instead of wound dressing or pruning paint in this case.

The fungus on a dead branch is usually only feeding on the decaying wood and is not something to be concerned about. You would just want to remove the dead branch and dispose of it. But some fungi (Armillaria spp., Phytophthora spp.) destroy healthy roots and lead to total tree failure, so be careful about how cavalier an approach you take. A google image search should help you decide if you have one of these problem fungi. If you are not sure, call a certified arborist or a consulting arborist. You can find an ISA Certified Arborist at

though membership in the American Society of Consulting Arborists is a good criterion for selecting an arborist in cases like this.

Good luck, Keith Babberney ISA Certified Arborist #TX-236

[Travis]

The latest recommendation is to *not* paint the cuts.