Best practice for unburying trunks from mulch volcanoes.

colb

colb

Been here a while
Location
Florida
Is anyone aware of legitimate best practices for unburying trunk from mulch volcanoes? My primary issue is that I expect the tree to adapt it's above-ground physiology to become below-ground physiology, over time. I have no support for this expectation, and no idea of the timeline over which it would take place. Should all mulch volcanoes be excavated? Should they be excavated only if they are recent? Has anyone researched it?
 
I'll assume you mean that an adventitious root system will be formed from the buried trunk tissue AND that said buried trunk tissue will adapt to being below grade and not rot.

Perhaps. Some species such as maple and linden will send out adventitious roots in high numbers in this situations. As far as not eventually decaying, I don't have any actual data as far as which species are more likely to rot or not.

Downside to rooting out adventitiously in a volcano or other deep conditions is the proliferation of stem girdling roots. Again, some species seem worse than others.

I usually push for RCX and SGR pruning unless I find trees that are obviously girdled quite badly. I've had quite a bit of success preserving trees where basal decay was evident to begin with and removing the excess OM and soil has helped dry out and aerate said decayed areas.
 
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That's a good question, and I've wondered about the mechanisms involved, myself. Also, when the reverse condition is present... like trees planted on a slope that has eroded away and exposed the roots. Some of them bark over and resemble trunk wood more than roots, over time. So, would exposing the adventitious root growth to air and sunlight have this effect, and all be well? I've done this on fruit trees, where we mulched them too deep, and just cut the adventitious growth and any sprouting off. But, this was a buried graft thing, which is really a different situation. Those trees did respond very quickly and were fine, but the mulch had only been too deep for a year or so.

When I think about how many trees I've seen with one condition or the other... trunk tissue buried or roots exposed... it seems to me that in the latter case, most species adapt to it and it takes a long time before the tree succumbs, usually by falling over. In the buried trunk case, it seems that problems arise more quickly and the trees don't adapt so well. But this is purely a perception on my part, and I don't see too many of species that might not be so adversely affected. For example, a cypress might not get too upset by it, where a maple would. Still, it would seem to indicate that exposing the affected area and letting it return to above ground life would be the way to go... or at least in species that are showing signs of decay, etc. that are adversely affecting the tree. That's always been my approach, that letting it rot is bad, so get it dug back out. However, I did recently see a Pin Oak that was buried in fill dirt two feet up the trunk a few years back, and it seemed none the worse for it. It's slated for removal for reasons unrelated to its health, so I'm going to have to dig around the stump before I grind it out, and see what's going on down under there.
 
My usual approach is to remove the mulch and/or restore the soil grade with either a pneumatic tool or the leaf rake/hand cultivator/hand pick/blower/shovel field expedient method. Then, if the customer is tolerant of temporary unsightliness, I'll allow many of the adventitious roots to air prune and tell me what needs to happen. This works well when I suspect girdling roots or other problems but can't tell on cursory inspection. I get to charge for a RCX that needs to happen either way, and then bid again on what I find; this seems to work out better for both parties. It's also great for targets of opportunity-can do the RCX with tools that stay on the truck for a nominal extra fee on the current job, and then recommend girdling root removal, additional work with am air tool, soil testing, etc...depending on what's going on.

I don't have any non-anecdotal data on tissue change under the mulch, but I haven't lost anything yet doing this stuff into December in Philly. The production of suberin or whatever it is that happens to adapt to the new environment seems to happen pretty quickly.

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Good post, Jeff. A couple of observations, I would agree with your feeling that buried is worse than too high. We have a lot of surface root issues here due to compacted soils everywhere. Doesn't seem to bother trees, only people.

Spruce trees really don't seem to be bothered from having buried trunks, maybe because they've buried themselves for millions of years?

I've heard but cannot cite or verify, that there is a sort of thermometer in the root flare area, that sends messages to other tree parts about how to act at different times. Could be a total farse of an idea...

About the grafts... I've been looking at a lot of grafts/ root flares a bit closer recently and have been wondering about which was which in certain cases, especially ornamentals and fruit tree.
 
fall_risk said:
My usual approach is to remove the mulch and/or restore the soil grade with either a pneumatic tool or the leaf rake/hand cultivator/hand pick/blower/shovel field expedient method. Then, if the customer is tolerant of temporary unsightliness, I'll allow many of the adventitious roots to air prune and tell me what needs to happen. This works well when I suspect girdling roots or other problems but can't tell on cursory inspection. I get to charge for a RCX that needs to happen either way, and then bid again on what I find; this seems to work out better for both parties. It's also great for targets of opportunity-can do the RCX with tools that stay on the truck for a nominal extra fee on the current job, and then recommend girdling root removal, additional work with am air tool, soil testing, etc...depending on what's going on.

I don't have any non-anecdotal data on tissue change under the mulch, but I haven't lost anything yet doing this stuff into December in Philly. The production of suberin or whatever it is that happens to adapt to the new environment seems to happen pretty quickly.

Sent from my XT1650 using Tapatalk
Click to expand...
Good point about billing/bidding in stages. We learned the hard way to charge an initial fee for excavation/exploration and charge extra if it turns into a lot of work!
 
Levi.CO said:
Spruce trees really don't seem to be bothered...
Click to expand...

There's a guy about five blocks from me who dumps grass clippings 2 feet deep around his spruce tree. I was going to tell him it was a bad idea, but I know he'd just give me the old, "That's the way dad did it back on the farm!" or something similar, so I haven't said anything to him. Stopped over awhile back to have a beer with him and looked at the trunk of the thing under the "mulch" and you're right, @Levi.CO, it doesn't seem to even care. I'd forgotten about those thing's habit of poisoning the ground under them and dropping enough litter to bury the weeds. Those are tough trees, and do real well here in Nebraska, too. Very rare to see an ugly spruce tree around here.
 
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Levi you might be thinking of hormones such as cytokinins that are produced in the roots and sent upwards to the canopy based on environmental stimuli and other growth hormones. Dont know if that applies to the roote flare area or not.

Or your thinking of something else. I don't know. I'm not in your head.

Or am I...
 
A garden hose and sprayer nozzle can help a lot. Usually readily available at a home. Works much better if there is a downhill drain, rather than forming a puddle.
 
Thanks guys, I'm getting two clear messages:

1. There may not be a body of primary literature about this.

2. In the field, dealing with adventitious roots (particularly girdling) is a recurring, noticeable downside to leaving a trunk buried.
 
You can probably add deep planting in and of its self can be fatal for new transplants in heavy/fine textured soils.

One could get away with it longer in sandy soils I would suspect.
 
I would agree that there is some literature to support the practice. I'm sure it's also covered in Arboriculture by Harris, Clark, and Matheny.
 
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