Another large oak with armillaria

[ronellis]

Like oak tree of the other poster (solvent), the large oak in my front yard has contracted armillaria. My arborist has recommended removal. I asked about removing soil around the roots adjacent to the trunk to assess the extent of the damage, but he believes that since armillaria is terminal, any treatment would be futile.

I will be seeking a second opinion from another local arborist, but I'd also like the board's feedback on an approach that I'm considering.

First I would like to aerate the root zone and try the organic Sick Tree Treatment developed by Howard Garrett. Details are here: http://www.dirtdoctor.com/view_question.php?id=130

Second, in the spring - after any danger of a freeze, I'd like to have the soil removed from the base of the tree, so that the major roots can be examined to determine the extent of root loss or damage. According to this article: http://cru.cahe.wsu.edu/CEPublications/eb1776/eb1776.html (9th and 10th paragraphs), removing the soil, air-drying the roots, and removing diseased tissue can potentially aid in survival.

Of course, if when the soil is removed, it is apparent that the tree is a hazard, I will proceed with removal.

My questions are:

Is it reasonable to expect that an arborist will be able to evaluate the viability of the root system or the extent of the damage to the root system if the soil is removed?

Does this approach make sense? Do you think it may be effective? Anything you would add? What would you do differently?

Am I wasting my time and money trying to treat armillaria?

My primary goal is to try to save the tree. If that is not possible, I would like to at least delay its demise as long as possible without putting anyone at risk.

Below is a picture of the tree and a picture of the armillaria mushrooms.

Thank you in advance for your opinions and feedback.

 

[treeseer]

My arborist has recommended removal. I asked about removing soil around the roots adjacent to the trunk to assess the extent of the damage, but he believes that since armillaria is terminal, any treatment would be futile.

I will be seeking a second opinion from another local arborist

That's good idea; the first guy gave a hack opinion.

"Trees and shrubs which are not seriously affected may be helped. The soil should be removed from around the rotted parts of the trunk and larger roots to allow them to air dry. The infected areas should be cut out down to the healthy tissue and diseased tissues destroyed. Wash cutting tools in soap and water and sterilize them in rubbing alcohol afterward. Roots should be left exposed during summer, but covered over before freezing fall weather."

Great update from WSU--totally in sync with standard references and practices. No need to wait until spring--get the second arborist to do a complete inspection of the infection when he comes.

O and a LOT of fungi resemble armillaria--be sure of the ID by seeing fungal mats and shoestrings before believing it. yes weeding mulching aerating would be a great idea.

 

[BCMA]

Like oak tree of the other poster (solvent), the large oak in my front yard has contracted armillaria. My arborist has recommended removal. I asked about removing soil around the roots adjacent to the trunk to assess the extent of the damage, but he believes that since armillaria is terminal, any treatment would be futile.

I will be seeking a second opinion from another local arborist, but I'd also like the board's feedback on an approach that I'm considering.

Please make sure that the recommendations you are receiving is from a “qualified” arborist. Managing root diseases and making recommendations whether or not to condemn the tree requires some real skill.

First I would like to aerate the root zone and try the organic Sick Tree Treatment developed by Howard Garrett. Details are here: http://www.dirtdoctor.com/view_question.php?id=130

I would recommend performing a “root collar examination/excavation ASAP. Remove the soil and turf and expose the top of the buttress roots. To begin with, remove the turf at least four feet or more from the trunk. You want to reduce the turfs competition with the tree roots.

I would also recommend top-dressing the entire drip-line of the tree with compost, including the area where the turf is removed. The compost where the turf is removed should be about 2” deep and 1/2” deep over any turf. The compost we use is composted municipal bio-solids (sewer sludge) mixed with Douglas fir bark. Check with your local extension to see if this is available in your area. The compost is rich in microbes and beneficials that will improve soil structure, and possibly attack pathogens. It will also add organic material and nutrients to the soil.

Second, in the spring - after any danger of a freeze, I'd like to have the soil removed from the base of the tree, so that the major roots can be examined to determine the extent of root loss or damage. According to this article: http://cru.cahe.wsu.edu/CEPublicatio...76/eb1776.html (9th and 10th paragraphs), removing the soil, air-drying the roots, and removing diseased tissue can potentially aid in survival.

This is good advice, but I would not wait until spring. Sooner the better.

Of course, if when the soil is removed, it is apparent that the tree is a hazard, I will proceed with removal.

My questions are:

Is it reasonable to expect that an arborist will be able to evaluate the viability of the root system or the extent of the damage to the root system if the soil is removed?

Yes, if the arborist is qualified. Check his credentials. You might need to find a qualified arborist on the ASCA website. http://www.asca-consultants.org/

Does this approach make sense? Do you think it may be effective? Anything you would add? What would you do differently?

You are on the right track.

Am I wasting my time and money trying to treat armillaria?

I do not think so. You will not be able to repair the damage that has already been done, but you might be able to increase the tree vigor to help it resist the spread of the disease. If you can determine the extent of the infection, you might be able to trace along the outside edge of the infection to keep it from spreading.

My primary goal is to try to save the tree. If that is not possible, I would like to at least delay its demise as long as possible without putting anyone at risk.

A risk assessment by a qualified arborist is in order.


Below is a picture of the tree and a picture of the armillaria mushrooms.


Thank you in advance for your opinions and feedback.

 

[treeseer]

I would recommend performing a “root collar examination/excavation ASAP. Remove the soil and turf and expose the top of the buttress roots.

Yes, assessing condition is Job #1.

To begin with, remove the turf at least four feet or more from the trunk. You want to reduce the turfs competition with the tree roots. I would also recommend top-dressing the entire drip-line of the tree with compost, including the area where the turf is removed. The compost where the turf is removed should be about 2” deep and 1/2” deep over any turf. The compost we use is composted municipal bio-solids (sewer sludge) mixed with Douglas fir bark. Check with your local extension to see if this is available in your area. The compost is rich in microbes and beneficials that will improve soil structure, and possibly attack pathogens. It will also add organic material and nutrients to the soil.

This would be a wonderful treatment, AFTER the risk assessment is done and the owner decides the tree will stay. The cart has moved ahead of the horse here--no Rx before the RCX is done!

Also, advising turf removal can be a green light to tree root removal--best to detail smothering or spraying instead of digging.

Also, an ASCA arborist may not be experienced at this--they may not have experience getting their hands dirty...

And, if anyone who owns a dozen chainsws recommends removal without examining the root crown, take that for what it is worth...nada.

 

[S Mc]

As Treeseer has stated, getting a positive ID on this is the first step. I would think you could take a mushroom to your local extension agency and get a confirmation.

Aeriation of soil, providing mulch rings, proper irrigation, refraining from fertilizing and the use of herbicide products are all excellent ideas and, whatever the outcome on your oak, I would encourage you to provide for the rest of your trees. If armillaria is in the soil, it can attack any tree that is susceptible and stressed.

A couple of comments re the Dirt Doctor link, although much of it is very good information.

Soil augmentation is site specific, so I would not haphazardly start amending anything without determining whether it is even necessary. It could be contraindicated or a waste of money.

Mycorrhizae is present in your soil. After the armillaria is dealt with you may wish to add an inoculum as a "shot-in-the-arm"; however, it is there. Fertilizing can and does inhibit the tree's relationship with this important soil fungi and should not be used. It is much more important to have the tree establish the symbiotic relationship with the mychorrhizal fungi as it enhances the tree's defence system, among its many other beneficial attributes.

Any product which acts as a fungicide, whether organic or not, has the potential to disrupt the mycorrhizae as well as the damaging agent. So use discretion here.

After you have determined the presence of armillaria and dealt with it (and you have been given some excellent advice here so I won't bother to reiterate), do follow through with the recommendations of mulching and proper care. We also use native tree trimmings as a mulch and highly recommend them.

Another comment, the root excavation in itself should be comprehensive enough to show the extent of damage to the tree and compromised roots. A separate risk assessment sounds like an unnecessary added expense. There is a large tree with a house as a target. It will be your decision based on the examination results on whether this is within your acceptable level of risk. The outcome will be up to you.

Sylvia

 

[Ed Roland]

Fertilizing can and does inhibit the tree's relationship with this important soil fungi and should not be used. Sylvia

Syvia, Should we say "phosphorous fertilizers" here? Maintaining the vigor of the tree can help resist Armillaria attack. After our guest speaker friday I have thought constantly about mycorr and it's benefits.

Here in SC Clemson University works closely with the peach farmers and has some recommendations for controlling armillaria in local orchards. Does not translate well into a recommendation for an urban scenario, though.

"Infested sites can be fumigated, but often this procedure will not prevent recurrence of the disease. Physical barriers to contain infection centers have been used successfully in orchards. Four-foot trenches are dug around the infection center and plastic tarp is laid inside the trench wall from bottom to top before the soil is replaced. The tarp prevents healthy roots from coming in contact with diseased ones, thus preventing spread of the disease."

 

[treeseer]

I agree Syl; you were painting with a broad brush there. Since the fungi harvest nutrients they are not inimical to them, unless it's raw urea or some other nasty burning stuff.

Clemson like most U's is so old school; methyl bromide and other such nuclear options. Not even sure that is the bmp for prepping groves. On existing trees, lots of sources agree cutting out the infection and digging out/replacing/inoculating the surrounding soil can be very effective.

Hey weas who spoke at Clemson? We just had Jim Urban talk to the LA's at NCSU, nice myth-busting he does.

 

[Ed Roland]

Hey weas who spoke at Clemson? We just had Jim Urban talk to the LA's at NCSU, nice myth-busting he does.

My post made it sound as if The speaker was affiliated with Clemson. Not so much. The guest speaker is a plant path that graciously entertained questions, via teleconference, from 4 curious arborists interested in learning some, in depth, soil science.
Part of our journey to attain the status currently held by, at least, two members here.

I wood appreciate face time with a landscape architect the caliber of Jim Urban.

And Yeah, the nuclear option of fumigating the soil is disturbing. I hear its done more on the west coast as a spot treatment for grapes, avacado, etc.

 

[S Mc]

I will stand by my "broad brush". To elaborate, the symbiotic relationship between trees and mycorrhizal fungi is important on many levels. In fact mandatory for some species and oaks are one of the obligates. It has been substantiated in many studies that fertilization can and does interfer with that relationship. So whereas you might see a stimulation of growth due to the fertilizer, this is not improving the vigor of the tree in the sense that it stimulates its defense ability. This, when fighting off a disease, is exactly where the invigoration needs to go.

The microbiology in the soil is a delicate system and one that is constantly being interferred with by many cultural practices including fertilization. I would much rather see, after the initial tx regimen suggested for addressing armillaria, the application of mulch (preferrably in the form of whole tree chips) which would supply the necessary nutrients in the ultimate slow release as the natural process of decomposition takes place. This allows the microorganisms, all of them, to develop and do their job.

Whereas our discussion last week focused somewhat on phosphorus and the contraindication of its application, I also believe our guest speaker was trying to impart the important fact that when we supply nutrients artificially the tree does not develop this important relationship or even gives up an established one. I feel that the fact that fertilization does not assist in the tree's defense is very important.

I, too, have been thinking constantly about the ramifications of what we do that inadvertently adversely affects the beneficial environment for our trees and how best to apply this information.

Sylvia

 

[Ed Roland]

Whereas our discussion last week focused somewhat on phosphorus and the contraindication of its application, I also believe our guest speaker was trying to impart the important fact that when we supply nutrients artificially the tree does not develop this important relationship or even gives up an established one. I feel that the fact that fertilization does not assist in the tree's defense is very important.

Sylvia

At the risk of hijacking the thread: clearly many fertilizer regimens push top growth at the expense of root development (the bags of macros sold by sponsor's of this site) making plants vulnerable to stressful environments. Frequent, high levels of fertilizer can produce an unbalanced and often unsustainable shoot-to-root ratio. The P disrupts the alliance between the fine root hairs and Mycorrhizae. Mycorrhizae on the other hand, feed plants and stimulate root growth.
Got it, But after testing, if it is determined the soil lacks a sufficient amount of a necessary element it should be added. If that element is potassium we can add granite dust, wood ash, potash rock or some other potassium rich organic matter without harming mycorr. populations.

 

[treeseer]

mmmm I think he's gotcha there Syl...

 

[S Mc]

At the risk of hijacking the thread: clearly many fertilizer regimens push top growth at the expense of root development (the bags of macros sold by sponsor's of this site) making plants vulnerable to stressful environments. Frequent, high levels of fertilizer can produce an unbalanced and often unsustainable shoot-to-root ratio. The P disrupts the alliance between the fine root hairs and Mycorrhizae. Mycorrhizae on the other hand, feed plants and stimulate root growth.
Got it, But after testing, if it is determined the soil lacks a sufficient amount of a necessary element it should be added. If that element is potassium we can add granite dust, wood ash, potash rock or some other potassium rich organic matter without harming mycorr. populations.

Ed, I do not disagree with what you have stated. I just urge you to not isolate the heavily fertilized with P as the only inhibitor, but to understand that fertilizing in general can disrupt the relationship between the mycorr and tree. The fert may not "harm" the mycorr but it does interfer with the relationship and this, in turn, can be to the detriment of the tree. As remember, if the tree doesn't "need" the connection with the mycorr then it won't establish it. So if adding fertilizer disrupts this bond and, in this case this specie's need for this relationship is obligate, then, in my mind, fertilizing is doing more harm than good.

In this specific case, the homeowner will need to deal with the armillaria first (assuming it is in fact armillaria). Depending how invasive and disruptive those steps are, perhaps he may opt for an inoculum of mycor as a "boost" to assist with the reestablish of a healthy soil. Mycorrhizae can aid in defence; fertilizing does not.

So your scenario of testing the soil and determining what, if anything, is seriously lacking and then applying a minerally-based product to address the deficiency is, IMHO, the best advice you could give a client. But so often isolating a single element and trying to "fix" this one element is difficult and can end up in a vicious pendulum effect. So I will stay by my recommendation of allowing the environment to improve itself with naturally-decomposing organic matter.

I applaud this homeowner on trying to inform himself with all the facts and options before making any decision and hope this discussion has proved to be helpful.

Sylvia

 

[S Mc]

Had to take a short break to look up this information.

Per Harris' book Arboriculture, Integrated management of Landscape Trees, Shrubs and Vines.

Pg 285: "When phosphorus is not needed, application will increase soil salinity; could tie up micronutrients, ...and pollute surface water if soil to which phosphorus has been applied erodes."

I am picturing all the fall fertilization that occurs automatically that is phosphorus based.

Pg 285: "Potassium. Most soils contain enough potassium for woody plants....When leaf mulch is left on the ground, potassium is quite effectively replenished in surface soil because it leaches readily from organic matter."

Again, mulch rings.

Sylvia

 

[ronellis]

Thank you all very much for your contributions here. I must admit some of the discussion has gone over my head, so I want to make sure I understand. I also have some more questions, if you all are willing to indulge me.

First, I should have a root collar excavation and examination done. I am assuming that the excavation requires special tools and is not a DIY job. Is that correct? Obviously, I need a qualified arborist to do the examination.

I wrote in my original post that I would wait until spring to excavate the roots. The information from Washington State had indicated that the roots should dry all summer and that freezing temperatures should be avoided. Is it suggested that I have the excavation and exam done - maybe remove infected tissue - then re-bury the roots for winter? Should I re-excavate in the spring or summer for drying?

I will also aerate the root zone. But, if I understand correctly, the "sick tree treatment", or another fertilizing regimen, is only advised if a soil test indicates it is needed. For what its worth, all leaves and grass clippings have been mulched onto the lawn for the six years that I have owned the house.

With regard to applying the mycorrhizal fungi, I am confused. Is it being suggested that this is unnecessary? Will soil testing indicate if it's necessary? Could it be harmful?

My initial consultation was with one of the two ASCA registered consulting arborists in my area. I've also had arborists recommended to me that are on the ISA list for my area. Is there any other certification I should be looking for? Does anyone know someone they'd recommend in Central Texas?

I know this is a lot of questions, and I appreciate any responses you're willing to provide.

 

[Ekka]

If your soil flora and fauna is in good health i.e. (a chemical free garden that has a certain amount of organic matter), then the Armillaria spores will reduce in quantity as they are eaten or degraded by the natural life in the soil.

Armillaria is a week competitor so if your plants have a healthy symbiotic mycorrhizal partner; then you will have nothing to fear from infection as the mycelium will fight off the Armillaria attack with its own armoury of chemicals. The way to make sure that your Trees and Shrubs have a strong symbiotic partnership with a particular type of fungus, is not to use ANY Chemicals in your garden, no worm away, no lawn or plant fertilisers, no weed or pest killer. All the minerals that plants need are in the soil, the only thing you need is a healthy soil flora and fauna which will break down the grains of grit/sand so that plants can access this resource, so put some organic matter into the soil in your garden and this will power the life cycles of all soil flora and fauna.

--------------​

I would personally dig out the fruiting bodies and soil, go maybe 1' away from where they are and carefully (do this dry, no water) do this. Where the fruiting bodies are in contact with the tree parts I would carefully remove then treat that area as follows.

Soluable mixture of michorizal fungi, dash of urea, dash or glucose, dash of Silica (ah, the lost secret of plant panadol) and seasol/seaweed extract.

Make sure the soil you remove is bagged and removed from site. They say leave it in the stinking hot sun so the fungi gets cooked dead.

Replace soil with sandy loam mixture for that area as you may be revisiting it later.

Later, maybe 1 week do the root crown investigation yourself with a garden hose and hand trowel. Careful to not scrape off bark.

Look for anything unusual, take detailed pictures if need be. Mulch the area as wide as you can, simply spray turf beneath 1 week prior with weed killer (do not drench just a light spray on the lawn leaf tips). Prior to mulching drench with the same application as described above.

---------------​

Part of the reason this problem came about was due to the sterility of the environment beneath.

In cities trees often will not grow their true size or life expectancy due to a variety of negative constraints such as competing lawns, pollution, compacted soils, degraded soils, lack of soil microbial activity and beneficial fungi, lack of grafting with like species for additional resources, lack of shelter from other trees, herbicide damage, poor water management with changes to surface water run off and flow, hard landscapes intruding on root space etc. The list goes on and on, it is a truly an inhospitable environment for trees compared to natural forests.

 

[BCMA]

simply spray turf beneath 1 week prior with weed killer (do not drench just a light spray on the lawn leaf tips). Prior to mulching drench with the same application as described above.

.

Correction: I'm sure this was an oversight, but do not spray your turf with a weed killer around your tree. It may contain 2-4d or another harmful ingredient. Use very sparingly Round-Up or a herbicide containing glyphosate as the active ingredient. Be careful.

 

[treeseer]

First, I should have a root collar excavation and examination done. I am assuming that the excavation requires special tools and is not a DIY job. ...

Yes not because of tools but expertise.

Is there any other certification I should be looking for? Does anyone know someone they'd recommend in Central Texas?

Yes, see my pm. Your arborist should have experience managing fungi--certs obviously mean nothing on their own. Sorry to hear an RCA said Armillaria was always terminal--rubbish. It is also not a weak competitor that can be controlled by soil management alone.

When Ekka says "treat that area as follows. Soluable mixture of michorizal fungi, dash of urea, dash or glucose, dash of Silica (ah, the lost secret of plant panadol) and seasol/seaweed extract." I think he means the surrounding soil, NOT the tree itself and especially not the wound. Or did I read that wrong?

 

[Ekka]

Spraying round-up on a fine still morning at the rate of 10ml/litre on a tall lawn (uncut) will have NO EFFECT on soil or tree roots, done it hundreds of times.

You do not drench.

You do not drift.

You do walk systematically backwards, one application only no over layering.

Attempt not to make mountains out of mole hills with these trivial things, we are not aerial spraying a field with agent orange!

Guy, are you really so ignorant?

After so many documents and research you come up with rhetoric, good luck. :monkey: Stay in the dark, to be ignorant is one thing to try and get mileage out of it is stupidity.

Some of the best treatments dont come in a bottle from your nursery.

ronellis, I have PM'd you the answer, dont share it!

 

[treeseer]

Ron if you are curious, put some dark paper under the mushrooms and shake them. If white spores come out that indicates armillaria. One protocol for treating fungal infections is:

Expose: “…diseased trees have sometimes been saved by removing soil from around the root buttresses and root collar. The pathogen ceases growth in tissues thus exposed.” from Diseases of Trees p 326-330. Step 1 is removing mulch and groundcover from the infection site

Excavate: Helping Plants Survive Armillaria Root Rot (November 2003 issue of Tree Care Industry), the author describes the excavation of tissue infected with the fungus Armillaria. Step 2 is removing the rotted tissue.

Excise, with care: "Trees with cavities may be valuable enough to justify considerable work." from the book Arboriculture. Step 3 is tracing/trimming the last of the decayed tissue, taking care not to break into living tissue.

Examine: Look at the entire infection. “An unexamined life is not worth living” Socrates. “An unexamined tree is not worth keeping” Arborist credo.
Calculate strength loss, determine the tree's response. After the diagnosis, make a prognosis, telling the owner about the process and progress of the fungal strategies of wood decay.

After this, if the owner wants to keep the tree, all the weeding, soil inoculating etc. mentioned above is good. You are in a warmer climate than WSU; not sure that freezing is that great a concern. The cold also works against the fungus. Drying out out the infection is key--if you do cover the area, don't trap moisture against it for long.

The OSU info is good general info, as far as it goes, but does not address managing infected trees, so its relevance here is limited.

" I have PM'd you the answer, dont share it!"

If our combative (sorry no time) Australian friend is confident that his brand of breakfast cereal is THE answer to this tree's ills, what reason could there be to hide it?

 

[S Mc]

Thank you all very much for your contributions here. I must admit some of the discussion has gone over my head, so I want to make sure I understand. I also have some more questions, if you all are willing to indulge me.

Absolutely, that is why we have this forum.

First, I should have a root collar excavation and examination done. I am assuming that the excavation requires special tools and is not a DIY job. Is that correct? Obviously, I need a qualified arborist to do the examination.

Treeseer has given some excellent advice in this regards. But perhaps there is some part of this endeavor that you may assist with that might help with the expense (cleanup, etc.) Be sure to ask whoever you speak with and do not be afraid to be frank about your financial concerns.

I wrote in my original post that I would wait until spring to excavate the roots. The information from Washington State had indicated that the roots should dry all summer and that freezing temperatures should be avoided. Is it suggested that I have the excavation and exam done - maybe remove infected tissue - then re-bury the roots for winter? Should I re-excavate in the spring or summer for drying?

Again, as Treeseer mentioned, is freezing an issue where you live? If not, I would think you could proceed.

I will also aerate the root zone. But, if I understand correctly, the "sick tree treatment", or another fertilizing regimen, is only advised if a soil test indicates it is needed. For what its worth, all leaves and grass clippings have been mulched onto the lawn for the six years that I have owned the house.

With regard to applying the mycorrhizal fungi, I am confused. Is it being suggested that this is unnecessary? Will soil testing indicate if it's necessary? Could it be harmful?

Aereation of the root zone, IMHO, would be an excellent idea as compaction is harmful to the tree, will stress it out and allow the armillaria a better opportunity to take hold. And yes, any augmentation to soil should only be performed after a soil test and actually this should include a foliar sample to show what the tree has been able to uptake as what is present in the soil does not automatically translate into what the tree can access.

What I get concerned about on augmentation is that we keep trying to correct something by addressing just one aspect of it. This is very difficult to do without throwing another element out of whack. Which is why we so strongly recommend the mulch rings for trees. The slow decomposition of whole tree chips gives these elements back to the soil in as best of a manner we can achieve outside a natural forest setting. It is good that you are mulching the clippings and leaves back into your area. This helps provide the micronutrients trees need.

Mycorrhizal fungi is a beneficial component of a healthy soil environment and a necessary partner to many tree's wellbeing. It is considered an obligate host to some species, oaks being one of them. Our rather oblique discussion (sorry about that) about whether or not to inoculate with additional mycorrhizae was the thought that since this tree is stressed, perhaps this would not be a bad idea. It certainly wouldn't hurt. But whether you wish to go to that expense would probably be determined by the outcome of several of the initial and necessary steps that you will take.

As I said previously, I encourage you to provide the rest of your trees with mulch rings, getting the grass away from them (out to the drip line if possible).

Sylvia