I'm was at the Mnt Home VA today in Johnson city TN. Came across this beauty, the grounds here could host a school for tree disorders. Let's go through the diagnostic process. What do you see and what should we be looking at?
Sugar Maple Declining
- Thread starter Raintree
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I'm was at the Mnt Home VA today in Johnson city TN. Came across this beauty, the grounds here could host a school for tree disorders. Let's go through the diagnostic process. What do you see and what should we be looking at?
Good start, you'll notice the tree is in three stages. You have dead no leaves, dieing wilting leaves and live green leaves. This tells us the issue is still active and progressing. The dead still has small twigs so we can assume an acute (rapid) decline. Not a chronic (long-term) decline.
The next step I would be interesting in knowing is the issue biotic or abiotic?
So what signs would help us determine this? Remember keep in mind what we already know, it's acute and active.
The next step I would be interesting in knowing is the issue biotic or abiotic?
So what signs would help us determine this? Remember keep in mind what we already know, it's acute and active.
I would first look at branches that still have some green, but have started to die back. Look closely at the twig - what do you see?
Abnormalities on the bark?
Holes in the bark?
Discoloration?
Is the wood discolored/stained?
What do the leaves look like? The brown ones...anything observed besides "brown"?
How do the green leaves just below those brown leaves look? How do the green leaves on the best part of the tree look?
Now lets look around the trunk. Any holes or other damage? Any fungal fruiting bodies or evidence of fruiting bodies that have been removed. Is the bark intact all the way around (tap with a mallet to listen if it is coming loose)? Are we counting this as a removal so I am allowed to cut a chunk out of the bar (looking for discoloration or galleries).
Same questions at the root collar.
Start asking questions of the owner/manager:
Has the tree been watered? Has the lawn been watered? If so, what was the source for that water? Anything different than others on the property?
Have there been any construction projects or anything that would have excavated or compacted soil around the tree?
Any drainage changes that would have impacted the tree with either more or less water?
Have there been other trees in the vicinity that have been removed? Were they dead or alive when removed?
What herbicides have been used?
____
Having said all of that, my first gut reaction is to say "look for verticillium", but I try hard to evaluate those other questions first to avoid tunnel vision (what was the heart medicine commercial that was something about zebra hooves, not horses???) A bad Japanese maple scale is another real possibility.
Abnormalities on the bark?
Holes in the bark?
Discoloration?
Is the wood discolored/stained?
What do the leaves look like? The brown ones...anything observed besides "brown"?
How do the green leaves just below those brown leaves look? How do the green leaves on the best part of the tree look?
Now lets look around the trunk. Any holes or other damage? Any fungal fruiting bodies or evidence of fruiting bodies that have been removed. Is the bark intact all the way around (tap with a mallet to listen if it is coming loose)? Are we counting this as a removal so I am allowed to cut a chunk out of the bar (looking for discoloration or galleries).
Same questions at the root collar.
Start asking questions of the owner/manager:
Has the tree been watered? Has the lawn been watered? If so, what was the source for that water? Anything different than others on the property?
Have there been any construction projects or anything that would have excavated or compacted soil around the tree?
Any drainage changes that would have impacted the tree with either more or less water?
Have there been other trees in the vicinity that have been removed? Were they dead or alive when removed?
What herbicides have been used?
____
Having said all of that, my first gut reaction is to say "look for verticillium", but I try hard to evaluate those other questions first to avoid tunnel vision (what was the heart medicine commercial that was something about zebra hooves, not horses???) A bad Japanese maple scale is another real possibility.
yes...bugs, fungus, bacteria, etc...for biotic. Abiotic is could also be soil conditions, physical damage, lightning, etc..
Yes, biotic living, abiotic environmental.
(The answer to this question is in the last post I made.)
(The answer to this question is in the last post I made.)
Excellent ATH, close examination of all the visible tree components. Here's a few more pictures. 
Is Toro Blight biotic or abiotic? (or is that Deere damage?)
As I walked up to this maple the first thought was verticillium wilt. What impressed me was the speed of the decline. You don't see a tree of this size with a full crown succumb in 2 years from verticillium often. It's possible however unusual. What other factors are possibly in play here?
That lawnmower damage is nothing new to that tree. So I don't think we can say that is the "immediate cause". Certainly I'd say it is likely a contributing factor to what we see.
I suspect the black dots are phytophthora bleeding canker? But maybe Botryosphaeria? Or maybe an insect? I need to cut a chunk of bark away to get a better idea. Destructive sampling isn't going to cause more harm to this tree, but the client may not be on board with it. If I see galleries under those black spots, we'll have a better indication that it is insect damage (but that alone doesn't rule out the fungal pathogens). Otherwise, we can send to a lab for diagnosis.
Is that, then, the cause of the dieback? Possibly. Neither of those show up overnight. Verticillium could still be at play. Is that just me wanting my original guess to be right? Possibly. An otherwise healthy tree can live with Verticillium. However, once it is looses vigor, the wilt fungus plugs vascular tissue more rapidly than the tree can respond - especially if it has been hot and dry. Having said that, I'm a little less keen on verticillium and more so on phytophthora after those latest pics.
I suspect the black dots are phytophthora bleeding canker? But maybe Botryosphaeria? Or maybe an insect? I need to cut a chunk of bark away to get a better idea. Destructive sampling isn't going to cause more harm to this tree, but the client may not be on board with it. If I see galleries under those black spots, we'll have a better indication that it is insect damage (but that alone doesn't rule out the fungal pathogens). Otherwise, we can send to a lab for diagnosis.
Is that, then, the cause of the dieback? Possibly. Neither of those show up overnight. Verticillium could still be at play. Is that just me wanting my original guess to be right? Possibly. An otherwise healthy tree can live with Verticillium. However, once it is looses vigor, the wilt fungus plugs vascular tissue more rapidly than the tree can respond - especially if it has been hot and dry. Having said that, I'm a little less keen on verticillium and more so on phytophthora after those latest pics.
Some good responses, I believe ATH is pretty much on target.
First we have the abiotic stressors.
Mechanical damage to root flare and surface roots.
Sugar maple growing in a hot dry environment in clay soils, most likely unfavorable pH.
Without lab work we can only speculate from experience.
Second we have the biotic pathogens.
I agree with ATH that verticillium wilt being opportunistic has killed this tree. The maple was holding it's own but experiencing a chronic case of verticillium active in the heart wood spreading throughout the tree. The symptoms would have been yellowing and scorching of the leaves.
Then a secondary pathogen bleeding canker started to take hold also taking advantage of a weakened tree.
This then triggered the verticillium to go acute and enter the sap wood, shutting down the trees vascular system quickly.
The sad thing is a simple inexpensive mulch bed would have saved this maple.
First we have the abiotic stressors.
Mechanical damage to root flare and surface roots.
Sugar maple growing in a hot dry environment in clay soils, most likely unfavorable pH.
Without lab work we can only speculate from experience.
Second we have the biotic pathogens.
I agree with ATH that verticillium wilt being opportunistic has killed this tree. The maple was holding it's own but experiencing a chronic case of verticillium active in the heart wood spreading throughout the tree. The symptoms would have been yellowing and scorching of the leaves.
Then a secondary pathogen bleeding canker started to take hold also taking advantage of a weakened tree.
This then triggered the verticillium to go acute and enter the sap wood, shutting down the trees vascular system quickly.
The sad thing is a simple inexpensive mulch bed would have saved this maple.
Galleries are the "lines" insects feeding under the bark leave behind.
"Wilt" is a symptom, not a disease. It can be caused by many things. Fungal wilt is wilting caused by fungus - in many cases by plugging vascular tissue. 3 well-known examples of this are:
*Verticillium (on a wide variety of genera)
*Ophiostoma ulmi and Ophiostoma novo-ulmi - collectively know as Dutch Elm Disease (which is a disease from Asia attacking primarily American trees...)
*Bretziella fagacearum known by its common name Oak wilt.
Dutch elm disease could just have well been called "Elm wilt". Oak wilt could have been called "Minnesota oak disease".
