Summer leaf browning in oaks

Nish

Nish

Branched out member
Location
North Carolina
What in general can be known about the prospects of a tree whose leaves turn brown in the heat and dry spells of a southeastern summer? Just now I am thinking in particular of two oaks where this was precipitated by lightning. Homeowners request removal. One, a big willow oak, I've already removed. No green leaves, but except for the one large lightning struck limb, I found the wood and bark to be sound and "green", and all the little twiggy tips were intact. The other is a large white oak in a similar state, and I've yet to address it. Everyone would be pleased if this second tree survives, but it will be harder to remove if it begins to decay.
 
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Quick thoughts as I leave.

1. removal without assessment is malpractice
2. browning from drought may or may not be a problem
3. drought has occurred over the evolutionary life of the species and likely your tree can handle it
4. green indicates live tissue
5. decay is not an immediate process, strength is not lost within a year in most case
6. time may be the best friend of the tree
7. even if the tree has to be removed test it then for strength loss etc.
 
Thanks Mr. Tree. On that removed tree, the client was a botanist and showed no interest in being second guessed by a mere tree worker. Still maybe I should have forced a reconsideration.
 
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That is not a surprise, a professor with a Ph.D. is not likely to accept the word of somebody who has no education (I have no idea your credentials, etc.) when the topic at hand is within their realm of their knowledge. In general tree guys are not considered to be knowledge based professionals. This is a great example where formal education may have been useful, also a formal inspection.

I was involved in a case last week where the two (other) arborists writing reports and the city staff did nothing more than view the tree at a distance. I visually examined the trunk, tapped with a hammer, traced the one root purported to be lifting the sidewalk, performed a sonic tomography to check for decay and climbed the tree to inspect for any hidden decay/cavities and in particular looked for ant holes. All this set me apart in the clients mind, as well as the knowledge and experience.

Sometimes you have to promote yourself to the client. The machines that go bing really helped in the above case.
 
@mrtree; A few questions, if you don't mind. First, how expensive is that sonic tomography machine, if you don't mind my asking, and how well does it work?

Also, what does the presence of ant holes indicate? I just climbed a black walnut tree yesterday, and when I cut off one parricular piece of deadwood, maybe two inches in diameter, the ants just came pouring out of a tiny hole in the dead center of the remaining stub. It was the only piece of deadwood in this tree that had that happen. Do you think this might mean the tree is in a great state of decline? Any insight you can give would be greatly appreciated.

Thanks in advance for any answers you choose to provide.

Tim
 
First, how expensive is that sonic tomography machine, if you don't mind my asking, and how well does it work?

There are four sonic tomographs on the market, the ones I know range from about $12 000 USD to about $20 000. They work quite well but have their limitations and operator knowledge is very important. You should also have a resistograph (another $10 000 USD or so) to confirm some of the tomograph findings. The truth is you cannot visually assess the cross-section of a stem without advanced equipment.

Also, what does the presence of ant holes indicate?

Ant holes indicate the presence of ants and therefore the presence of decayed wood. You must understand a little about ants to interpret ant holes. There are a couple of general books to start with:
Ants of North America: A guide to the genera by Fsher and Cover
A Field Guide to the Ants of New England by Ellison, Gotelli, Farnsworth and Alpert

More Detailed information, and likely more important for tree structure is:
Carpenter Ants of the United States and Canada by Hansen


I just climbed a black walnut tree yesterday, and when I cut off one particular piece of deadwood, maybe two inches in diameter, the ants just came pouring out of a tiny hole in the dead center of the remaining stub. It was the only piece of deadwood in this tree that had that happen. Do you think this might mean the tree is in a great state of decline? Any insight you can give would be greatly appreciated.

Ants in a limb/trunk indicates that decay is present but you must also assess the extent of decay and the tree vigor/vitality. The mere presence of ants is not a significant hazard but it is a signal that you need to know more. If you are going to consult you should try to determine the Genus as this can tell you a lot about the ecological niche and may be a clue to reading the tree.
 
Study previous yrs increments of growth etc.
Study present yrs growth, bud size etc.
If things look typical? Good to high chance.
Less than typical? 50? 20%? Less? Mb give it a season wait to see how it leafs out.
Trees can survive defoliation/drought twigs and stems can photosynthesis enough to releaf.
 
On the white oak, improve the soil and prune next year. The botanist should understand that.

Botanists can often be persuaded by the right resources. attached has protocol for inspecting lightning damage and getting botanical data.

mrtree's description of detailed inspection is music! But bing machines are seldom needed imo and drills are seldom needed to get good tomo results. And if there is an open cavity, the interior can be inspected without bing machines.
Plus, sounding can be useful and fairly reliable.
 

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I had another look at the lightning struck white oak--it looks to be in bad shape. On the main trunk bark has was blown off around it's full circumference. Although from my own recent attempts to kill a client's maple for wildlife habitat, I've learned that trees can survive significant girdling wounds.
 
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