Planted too deeply and volcano mulch

southsoundtree

southsoundtree

Been here much more than a while
Location
Olympia, WA
We know that trees should be planted with the root crown at soil level, and mulch shouldn't be on the trunk. My question is why? One issue is stem girdling roots. What else happens when trees are too deep and the trunk is too moist, physiologically/ biologically-speaking?
 
Too much moisture or mulch = an anerobic environment, depending on the drainage of the soil. Too much mulch can cause hardiness delays and depending on what type of mulch, nitrogen deficiencies may occur. Furthermore, water has a hard time moving into different soil mediums, if the surrounding soil is finer for example, water will move around the root ball--only until the surrounding soil is saturated, will H20 move into the different soil medium. You can test this with different layers of sponges with different types of porosity. Just a few thoughts, however, biologically I think it comes down to lack of oxygen, we all know roots need oxygen and water.
 
Volcano mulching mulch against a tree trunk also makes a nice environment for fungus and bacteria that can cause rot in the lower trunk or cause other disease related issues. I like to tell people to think doughnuts, not volcanoes when mulching.

Nitrogen deficiencies in soil under mulch are a bit of a myth, UNLESS the mulch is incorporated into the soil. There is a slight deficiency at the interface but not much/nil in the rooting area, even just under the surface.

Here's an article about that (though I'd like to note that I'm NOT on board with a bunch of her other articles/thoughts). http://www.puyallup.wsu.edu/~linda%20cha...s/Woodchips.pdf
 
Pruning gal, I should have been more specific, It's my understanding that N deficiencies occur when the mulches decompose too quickly. In the case of woodchips, they breakdown slowly, not an issue. Sawdust or straw, on the other hand would decompose quickly. Incorporating into the soil is a different issue. Yes I agree--good pointing that out.
 
For one thing a tree will begin to develop superficial roots from the stem which will often become the primary root system, above the original. The original system begins to die, and decay can get into some critical areas that way. The tree often then begins to rely on this new root system for structure when it is in fact just an adventitious system without the developmental characteristics of the original root system, most importantly the root/stem interface that we call the flare.

That is one big reason. I could go on for an hour more, but I am pooped. Pruned, cabled and braced a 110 foot Tulip today. Tired now.

-Tom
 
also, roots have more suberin than stems, which means they can keep out water they don't want. Stems are more likely to rot in the presence of constant moisture.
 
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For one thing a tree will begin to develop superficial roots from the stem which will often become the primary root system, above the original

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These roots often grow tangential to the stem, instead of radially...leading to girdling roots.
 
These thoughts come from a Bartlett seminar I recently attended...

Soil against the trunk impedes the exchange of gases through the phloem, which can disrupt the flow of sugars/carbs to the roots.

He showed photos of an oak (I think) where the trunk "pot-bellied" at the raised grade...but there were no girdling roots after the RCX.
 
That's it.. the roots need to breathe.. they need the Oxygen. Lack of O2 hurts more than just the exchange of carbs IMO..
It impeeds the growth of the trunk flare which in turn, when retarded, is less able to hold the tree up when the wind blows.. Just look at trunk flares in natural grown trees.. they have a nice wide footprint..
 
My study finds that a lot of mulch on top of the soil does not cause nitrogen deficiency as long as its not mixed in with the soil itself.

Seems that 3 to 4 inches loose is plenty, and I usually thin it to a couple of inches near the trunk.

But larger trees are not the same as smaller trees. There are big trees in the forest that show beyond a shadow of doubt that they can handle 6 inches to 8 inches of compost-like material. But it happened slowly over time.

One thing that can happen to mulch, though not often, are mulch fires started by fireworks or sparks. If mulch gets dry and is several inches thick against the trunk, it can damage the tree.

I've only seen it a couple of times in like 20 years though. It's even less likely than shrub and tree fires from fireworks or cigarettes, which I've seen a half dozen of.
 
Learned something here today.
Long been aware of root 'suffocation' but I never considered the secondary roots that grow in the mulch having a tendency to girdle. I wonder why that would be?

So many HOs hear that mulch is a good thing and believe more is better and so have a s-load of it blown on to their trees and shrubs a foot or more deep.
We had an acreage where walking on the mulched beds was like walking on a trampoline (or like I felt when I drank too much codeine-based cough syrup).
The guy bought the property for all the ash trees taht were now slowly giving up and dying under the mulch.

And I guess this HO got his money's worth from his 'landscrapers'

Mulch piles (1) by altacal, on Flickr
 
When mulch installation is sold by the cubic yard it's nomsurprise that ther are volcanoes

Here's a Shigoistic term to remember about roots. They don't breath they respirate. Two different biological functions
 
Don't always blame the mulch. One of the main causes of the "volcano" look in my area is the landscapers edge around the tree every Spring and don't remove the edgings. That would increase their labor costs! We also have heavy clay soils and many times I will see trees planted halfway out of the ground. Its not so much the mulch IMO but the other cultural practices that are involved.

This has been an excellent source of revenue in regards to Air Spade work in trying to correct these issues.
 
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These thoughts come from a Bartlett seminar I recently attended...

Soil against the trunk impedes the exchange of gases through the phloem, which can disrupt the flow of sugars/carbs to the roots.

He showed photos of an oak (I think) where the trunk "pot-bellied" at the raised grade...but there were no girdling roots after the RCX.

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Is this cause the lenticels have been blocked? or is it based on the roots being suffocated?
 
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Is this cause the lenticels have been blocked? or is it based on the roots being suffocated?

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Both?

New lateral roots formed after the end is cut (as with b&b harvest) are often tangential and become SGR's.

Adventitious roots newly formed off the trunk circle much less often ime; most are radial that i see. and they are best left alone when the tree needs them.

attached a great article on adv roots.
 

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Adventitious roots newly formed off the trunk circle much less often ime; most are radial that i see. and they are best left alone when the tree needs them.

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Do you leave adventitious roots intact when lowering grade to the original root flare?

Or do you leave the grade above the adv. roots if the tree needs them?

My instinct is to lower grade to proper depth and remove adv. roots...but I haven't done RCX on a tree suffering from significant root loss.
 
Last year I went and looked at a sourwood tree that a client was having problems with, alot of decay around the base and loose enough to push over by hand. The tree was planted about 3 years prior by a nursery and they said it was getting worse every season. It looked like it was planted too deep and we replaced it but when we dug it up the root flare was a good 8 inches too low and almost all the origanl roots were rotted. Seems like alot of the newly planted trees have a volanco around the tree because guys just pile the edge they dig around the tree and then dump 4 inches of mulch on every year. I have to snap a pic of a couple plums that were planted at a store by me, the pile is a good 8-10 high around the trunk and every year it gets bigger, sadly the trees are looking worse every year and will probably have to be replaced in the near future.
 
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2. Furthermore, water has a hard time moving into different soil mediums, if the surrounding soil is finer for example, water will move around the root ball--only until the surrounding soil is saturated, will H20 move into the different soil medium. You can test this with different layers of sponges with different types of porosity.

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I've rearranged the paragraphs of your quotes to respond that I agree with the above that water will not move into other soil textures until its own texture is saturated. It is equally understood, as I understand it, that water will not drain from a finer texture for example, into gravel until that finer soil is saturated. So we have the paradoxical appearance of soils or a root ball that ought to “naturally” drain into a lower level with large pore spaces, but instead depending on circumstances could stay almost continually saturated and “drown” the roots in that finer soil.
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1. Too much moisture or mulch = an anerobic environment, depending on the drainage of the soil. Too much mulch can cause hardiness delays and depending on what type of mulch, nitrogen deficiencies may occur.

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I can't agree that simply too much moisture or mulch = an anaerobic environment. Generally, the technical definition means absence of oxygen. Perhaps a vacuum is an equally anaerobic environment.
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3. Just a few thoughts, however, biologically I think it comes down to lack of oxygen, we all know roots need oxygen and water.

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Please remember that we are describing a process and that is once oxygen is used successfully the carbon dioxide product has to be removed. If the carbon dioxide can't be removed from the pore spaces, oxygen can't be replaced and we are again in an anaerobic environment. When natural gas lines leak into the soil, do those nearby trees die because they have no oxygen or because they're poisoned by a petroleum product?

I don't know and I will carefully avoid testing any hypotheses personally. Live free breathe deeply...


Bob Wulkowicz
 
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My instinct is to lower grade to proper depth and remove adv. roots...

[/ QUOTE ]Mine too. If the adv roots are growing strong then it's often a tough call. Several times I've left adv root ends connected to the soil while clearing the trunk below them, in search of the flare. Dr. Smiley with Bartlett has suggested 1/4" or 1/2" as the max diameter to remove.

Coming up with general guidelines on this activity is a challenge; depends on the tree, every time. Here's a research paper pulled off the ISA website.
 

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