Damaged Oak - what to do?

[bobmuller]

About 5 years ago, a car struck an oak tree in our front yard. An arborist back then did some 'trimming' of the damaged area. There now appears to be rot, and what looks like sawdust and holes in the old wound. I've enclosed pictures. Any advice on what to do? I love this tree and don't want to see it go. View attachment 32623

View attachment 32624

 

[MiamiTree]

The wood inside the old wound is being eaten by insects (round head borer, damp wood termites) and is probably rotting from exposure to the elements. The tree seems to be healing fine and the hole should be completely covered in 15 to 20 years. I will leave the oak alone and let the tree finish sealing the wound on its own. Don't do any cutting around this area or apply any paint to it. Why is that light attached to the trunk? You are not suppose to put any nails directly on the trunk. I guess is fine in this case so no one else crashes into the tree again.

 

[rebelman]

There will be others more qualified than me to ring on this. I think the arborist scribed the wound, a fairly simple procedure I do on occasion. There are many factors involved, but many times a light crown cleaning and mulching the root zone can relieve stresses over time. Often I remove an oak because of scarring such as that, only to find that the scarring was minimal and removal unneeded. Many times customers say they love their trees, but won't mulch.

 

[bobmuller]

MiamiTree stated the holes were probably due to "round head borer, damp wood termites". Should I treat for these insects in any way? Great responses to my dilemma, thank you!

 

[MiamiTree]

I will just leave it alone. Let nature do its job. The tree has natural defenses against insects.

 

[treeseer]

I will just leave it alone. Let nature do its job. The tree has natural defenses against insects.

And I would excavate all loose decayed material, and all the insects therein.

They do tend to breed, you know; why have more? Plus, the more air and light in there, the worse the habitat for decay.

 

[rebelman]

I'm with Miami on this one, I don't think excavating decay is a good idea. You will breech a good border somewhere. Once nails are are in the tree, it's better they stay or if pulled the holes filled with liquid nail.

 

[MiamiTree]

You can read what Dr. Ed Gilman has to say about this type of injury at this link
http://hort.ifas.ufl.edu/woody/maturetreecare/Lowertrunk.htm

This area of the tree is very critical because it supports the entire tree.

Also read this link:

http://hort.ifas.ufl.edu/woody/maturetreecare/Canopy.htm

"Do not attempt to clean out the inside of the cavity or hollow. Do not drill holes in the bottom of the cavity to remove water. This is likely to spread decay to healthy living portions of the tree."

Your best bet if you want to be sure the tree is safe and doesn't need to be cut down is to get a qualified professional to use a resistograph tool on the wound.

You can read this link as well for info on this

http://hort.ifas.ufl.edu/woody/maturetreecare/decayfactor.htm

I hope this helps

Al

 

[treeseer]

You guys are right about homeowners excavating cavities; more harm than good can occur. I don't think Ed is saying that loose rotted insect-infested junk can not be scooped out.

"checking for decay in the center of the trunk using an appropriate device can help determine the stability of the tree."

A blunt instrument like a trowel is appropriate; a sharp device is not.

as far as what to do for the tree, call an arborist to look at the site. S/he will likely tell you to invigorate the root system, clean the crown and monitor.

 

[MiamiTree]

If the wound is completely excavated out of rotten and insect damaged wood wouldn't the new wood that becomes exposed begin to rot and get insect damaged in turn? The new wood will start to get sun that is true but it will also get wet when it rains and it will rot and then get more insects. When the car hit the tree 5 years ago it acted as an excavator of sorts and excavated the bark out into sound wood free of insects. As the five years went by the fresh wood rotted. If you take the rotted wood out wound't more wood begin to rot making the hole bigger?
Actually there are some insects that are attracted to the fresh wood more than the old rotted wood.

 

[rebelman]

If you take the rotted wood out wound't more wood begin to rot making the hole bigger

I don't think excavating the rotten wood is a good idea. However, if it is done, without breeching the sound wood, the sound wood should stay sound. Chemicals in the border zone, reaction wood should keep aerobic and anaerobic pathogens at bay. Wet or dry, the tree should be equipped to ward off further infection. But even a tiny breech of the barrier zone could allow pathogens access to new territory.

 

[MiamiTree]

Then there is no reason to take the rotting wood out. The insects will finish taking it out for you. The insects will not attack the new wood because of the chemicals and will only do their work on the old wood.

 

[treeseer]

Then there is no reason to take the rotting wood out. The insects will finish taking it out for you. The insects will not attack the new wood because of the chemicals and will only do their work on the old wood.

Sounds good in theory, but you are assuming that the barrier is formed solid. Often it is not.

You're also assuming that the wood beneath the rotted wood is not in the process of decay due in part to the presence of the rotted wood. I would submit that the rotting/rotted wood has active growth of fungal pathogens that get more aggressive as the volume they occupy increases.

I think it best to remove the infection, being very careful of boundaries.

 

[MiamiTree]

If this oak tree was in the forest without any human around to excavate the wound for it would it rot completely and topple over?

 

[rebelman]

Forest trees have different stresses than trees around people. the root zone is stable, roots are connected by beneficial fungus. The forest itself forms a windbreak. Cars don't hit trees in the forest. Bermuda grass doesn't battle roots in the forest, yard lights aren't nailed to trees in the forest. Trees in the forest aren't hacked by hacks(unless it's the urban forest).

 

[MiamiTree]

Very good points.

 

[pinus]

The rotted wood is proper environment with good microclimate for funguses and insects, but it is an good place for their enemies too, so...
In the forest, there are an other destructors. Starting from neighbour trees falling on them and damaging the bark and branches to mooses and deers cleaning their horns against trees...

 

[MiamiTree]

Pinus do you consider the damaged wood should be removed from this Oak or left alone like it is now?

 

[pinus]

It seem that the wound is a litlebit to big to recover with and/or without human help. There is two approaces here, as I noticed. Some people are advising the removal roted wood, but no cavity filling, some prefer not to touch tree. From mechanical srength viewpoint the cavity filling should be good. Hollow trunk will broken easier than filled with solid material. At the same time, depending from the used material and method the cavity fill can have some negative effect for the tree too.
On such tree, I´d removed only the rotted wood which can be removed "by hand", so, very soft layer and looked how much is it and what is behind it. Then can be made further desicions.

 

[treeseer]

I´d removed only the rotted wood which can be removed "by hand", so, very soft layer and looked how much is it and what is behind it. Then can be made further desicions.

Common sense, scientifically sound.