BIG OAK - Air Knife?

macrocarpa

macrocarpa

Branched out member
Location
Midwest
I have a client where they are attempting to preserve a 40in dbh black oak, but I know some of the grade has been changed and soil compacted.

Anyone have a lot of experience with verticle mulching/radial trenching with air knife? What trenching method and amendments you may recommend to incorporate in the soil? Alleviate compaction, decrease stresses, give the tree a boost - are the goals.

If giving the list of products is too much info to post, please pm me.

Thanks!
 
Hey Aaron, what's the history? How long ago was the grade change done?

Assuming they're willing, I like to change the grade back to original as far out as they will let me, then radial trench down to below root level at least out to the dripline and backfill with a mixture of native soil, compost, and vermiculite. I then mulch the whole area.

I excavated over 2' of soil from around the trunk of a 22" hickory last fall. We'll see how it does this year...
 
Change grade back to original as much as possible. Consider gypsum and mulch to alleviate soil compaction. From the research I've read it seems up in the air as to the effectiveness of radial trenching; maybe others have had different experiences though?

Seems along the line of the myth of tilling soil to help with compaction.

jp
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Change grade back to original as much as possible. Consider gypsum and mulch to alleviate soil compaction. From the research I've read it seems up in the air as to the effectiveness of radial trenching; maybe others have had different experiences though?

Seems along the line of the myth of tilling soil to help with compaction.

jp
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Compost will do the same as gypsum in most cases, from what ive read. Why not add the gypsum to your compost pile, and let it cook down with the rest of the OM?
 
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From the research I've read it seems up in the air as to the effectiveness of radial trenching; maybe others have had different experiences though?

[/ QUOTE ]VEry different. Great benefits on some oaks here. here's watson's original study--what research do you have that puts it up in the air?

tilling cuts all roots; not comparable to air blasting soil and not a myth.

definitely not for every tree; case by case. Got pics macro?
 
The history of this tree black oak: They actually designed a hospital around this tree, it was a forest tree. Unfortunately they did a poor job of protecting the critical root zone. Construction started 2-3 years ago. I did some pruning on it and treated it for ambrosia beetle (secondary from stress most likely). Fortunately I was able to control the beetle. The tree is leafing out good now, but I fear that with time the damage from the adjacent contruction will take its toll. At my request they said they tried to get the soil back to natural grade but I am not surehow close they actually got it or how they did it. I suspect lots of compaction and root damage took place. I was considering air spading and applying something like essential plus at the high rate, and then mulching. http://www.growthproducts.com/pages/arbor_care.asp?tables=featured&product=81

This is the only pic I have, from an article about the franklin woods hospital and the oak tree. http://www.newsandneighboronline.com/index.htm

Also, if anyone may be so kind, please pm me with what you may charge for a project like this?

Thanks for all the helpful posts.
 
Getting the natural beneficials back to the compacted soil, and moving around, will relieve more compaction and add more helath to that tree, than any chemical, spray, or air tool ever would.

The microbes, bacteria, worms, etc need to be brought back in, and FED. Compost the hell out of it. Radial trenches filled with local twigs, leaves, etc, and COMPOST, topdress with 2-3" of compost, and then put down 3"-4" of 6 month old wood chips. You will be amazed at what this will do for any tree.

Airtools are great, and so arent liquids. But we must build the soil backup, to feed the tree. If we simply feed the tree we are working backwards, feed the soil!


Oh yeah, DIRT is whats there now most likely, especially considering all the compaction. Soil is a living, breathing, thing. Soil is made and fed, dirt is dropped in place.
 
Bull, This is the ingredient list of the product I was considering, plus I would add mycho and maybe a couple other beneficial orgainics.

Derived from potassium humate, 21 natural L-amino acids, enzymes, simple & complex sugars, vitamins, kelp extracts, carbohydrates, hydrolyzed organic proteins, a natural wetting agent and natural biostimulants, Essential Plus has all the "building blocks" for plant and soil nutrition. Its broad variety of high quality ingredients dwarfs competitive products which typically contain only two or three ingredients at most
 
I don't know what kind of soil this tree is sitting in, but if you do radial trenching (and here I have heard the qualifiers on efficacy that Treesandsurf has --- at a James Urban lecture) I would NOT fill the trenches in with anything but well decomposed organic matter. You know, the stuff that is 80 to 90% decomposed, dark brown/black...smells really good.

You say this is a forest tree that the hospital was built around. Is there any native soil around you could access? This would have the soil biota the tree would be accustomed to and require. Even if you decide to top dress instead of radial trenching, this would be a good product for the top dressing to bring back in the desired microbial activity.

I know gypsum is recommended in loosening up heavy clay soil, but you want to be sure you do not already have a high calcium/lime content. And just because it is reputed to loosen up heavy clay soil, does that automatically translate to compacted soil due to construction?

Sylvia
 
Definitely agree that increasing OM content of a soil with compost amendments will do wonders for the soil ecosystem (biota, humus content etc.) and in turn help with compaction; however, the process of decomposition and mineralization associated with soil organic matter is hindered in anaerobic, compacted soils. And it is generally not recommended to have a higher OM content that the native soil present, typically contains. From this thread it sounds like the trees are present in a fairly undisturbed (except for the recent construction) forested habitat? OM content shouldn't be too low? More testing needed I guess.

With gypsum or calcium sulfate (lime) and mulching to help aerate the soil (by flocculating the soil and improving soil aggregation), you can hopefully improve soil aeration and water infiltration. I think both are needed.

Guy, breaking up the soil mechanically (air knife, tractor whatever) seems like a good recipe to destroy soil aggregation in the process. I'm not talking about roots.

Here's some more info worth reading:

http://joa.isa-arbor.com/request.asp?Jou...ue=6&Type=1

still a lot more research needed:

http://joa.isa-arbor.com/request.asp?Jou...ue=5&Type=1


jp
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Jon I do not think the gilman study transfers here; way differnet soil (about shich btw we knwo nothing really)

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And it is generally not recommended to have a higher OM content that the native soil present, typically contains.

[/ QUOTE ] wtf? this makes no sense to me; what general recommendation applies here? jeeprscreepers

macro, pm on way with proposal. article for general reference; refers to the work in china that was brought to isa via england
 

Attachments

all the info is given in the paper regarding the soil;

Millhopper fine sand (loamy, silicaceous, hyperthermic Grossarenic Paleudults) with less than 2% organic matter

A udic ultisol, low nutrient soil in a humid wet environment.

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And it is generally not recommended to have a higher OM content that the native soil present, typically contains.

wtf? this makes no sense to me; what general recommendation applies here? jeeprscreepers]

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trying to raise the om content in a soil that typically has say a 1.5% (sandy soil) is not that practical and not necessarily more effective in changing the chemical and biological properties of the soil.

if there is a known deficiency (which is very common when working with trees in the urban environment) then composting to try and raise the OM content (as well as mulching) would probably be a good idea. It may even be a good idea here, it just didn't seem from the story that OM content was necessarily low? we need more info about the soil and the conditions (btw, send me the address of the concern if you want and I'll do a survey on the area to get more info, if you like).

jp
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For my own curiosity,what studies have you read that stated that in a soil with low OM, adding OM may hinder the species in question? I havent seen any studies, doesnt mean they arent out there and I would love to read them!, that state this. Generally speaking the higher the OM present the better for the plant. Look at the forest floor. You can dig down a foot in the soil, and still be in the organic layer.
 
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For my own curiosity,what studies have you read that stated that in a soil with low OM, adding OM may hinder the species in question?

[/ QUOTE ]Jim I don't think Jon said that exactly. It'd be great if he got the info to do a better mapping so we could see the underground picture better.

it just drives me crazy to see a picture where the roots have obviously been trashed, with a caption crowing about how they saved the tree. no concept or respect for the lower half of the tree.
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The caption under the photo in the article is rather ironic, isn't it? "A massive oak preserved in one of the healing gardens."

This may have originally been in a forested setting, but is no longer. To assume this soil is still native and pristine would be in error, IMHO. The anthropogenic influences have altered that forever.

Guy, I'm right there with you on philosophies of preservation: so often we see people who have "saved" a tree during construction, when the only effort they truly made was not to physically cut it down right off the bat.

A note on soil surveys: they are not necessarily applicable for getting specifics off of a small area. During my Soil Science class one of the exercises we had was to look up a survey for three different areas within our community. I chose an urban site, a rural but under development site, and my own land. Whereas the urban site was spot on "too disturbed to list", the rural under development site was semi-accurate (I had watched digging a gravel pit and restoration in this area consistently for the past 10 years as it was on our way out of our community), but survey for our area, which should have been dead on as it has many undisturbed areas, was far off.

If you want a soil survey of the area you are planning on amending, I would suggest you do it yourself.

I'm not seeing how the research articles that Treesandsurf link from JOA are relevant in this situation as they are talking transplants rather than a mature tree in a construction site. I'm not saying they didn't have some interesting data; however, research is all well and good, but too often limited facts and hypotheses are then taken out of context and become overly emphasized in other settings.
 
definitely agree Sylvia, soil surveys can't replace field testing but they do give a great place to start from to figure out what you're working with.

as for the links relative to soil compaction, here's a more appropriate article:

http://joa.isa-arbor.com/request.asp?Jou...ue=2&Type=1

Jim, didn't mean to make it confusing. of course having a higher content of OM is almost always beneficial; what I was trying to say was that soil types function with different amounts of OM in their undisturbed state and that trying to raise it above that 'normal' level requires a lot of amendments and you haven't necessarily made any more Carbon available in the active pool.

of course in the urban environment OM content is often low because all the vegetation and leaf litter is removed etc. so amendments would be very beneficial.

jp
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A long probe will assess compaction and determine need for treaments. but the pic shows that impacts were considerable, despite claims to the contrary. lots of fill on the left side apparently. Mulch should be immediately applied, to lessen future damage from moisture stress.
 
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