What are relative effects of the Airspade & Terravent?

[Bundle 2]

Well please do! I would like to know more of the blasting, I know fineroots are being shot to treeheaven, but they are plentifull after a year of treatment with shootextensions of 30-50 cm so it cant be that bad. But as you said...another thread...

It would clearly depend on soil type to some extent, on the age class and species of the tree I would have thought, as the root generation processes have subtle differences at the various stages of development; an understanding of the effects on the mycorhizal communities would be important too.

This I say because, very often, those trees that would seem to warrant a program of decompaction are regularly already in more advanced stages of the life cycle. This would seem to suggest that mycorrhzi in the soil horizon, whilst present, are unable to function optimally. I suspect that blasting them to shreds ( very technical terminology!) does little to ameliorate the soils condition for the good. ( Young trees are not likely to have procured this same association as a result of the relatively brief timings involved.)

 

I am unclear in my own mind however, are mycorhizal fungi present in soils without the trees? If so, on what do they feed? I am fairly certain that during the successional colonisation of the UK by trees after the last glacial period came to an end, @ 12,000 years ago, the success of those trees with the associations we know about today, were less successful in their various habitats as a result of the handicap wrought of their absence, being forced as they were to colonise small, niche pockets, until the mycorhizi caught up with them on the march northwards.

And what of the incidence of causing embolloisms by the forced introduction of air into the vascular system? Does this actually occur? It is not outside the possibilities of science- logically there would seem to be no reason that this should not occur.

And of the Terravent. It would seem obvious that the introduction to the rootzone of a metal prod is inevitably going to have a negative effect everytime damage is caused to the roots from physical contact. The introduction of mycorizal innoculation would seem to be a good idea and yet, much is said to contradict an obvious benefit from such innoculations- and they are costly. Fools gold? Fertilisation may be a further benefit; more is known about the effects and efficacy of fertilization, as well as dosage. This an area of technical expertise however.

Finally, does the Terravent type decompaction only serve to hoist the soil, en masse, ony to then slam it back down. ( repeatedly) I for one am not convinced of the benefit from such a mechanism. Quite the opposite infact.

 

It was touched upon in an earlier discussion thread on this forum many moons ago, but the talk of the need for training in the use of airspades has been suggested. I am intuitively both for and against this for various reasons.

Practically, it is expensive whilst those involved are persuaded to generate income from what little is really known and understood about either of the processes. Little has been offered in discussion to dispel the myths and misconceptions.

 

I am in the process so to speak of acquiring some research into decompaction. I am not certain of the nature of said articles but certainly would hope to post them here when (if) they materialise.

In the meantime...all contributions to this thread are to be encouraged and they are welcome if it helps clarify those issues I have highlighted. Im sure there may be others. Likewise. Post away.

 

Ignorance, despite what we may have persuaded of in the past, is just that ; ignorance!

[David Humphries]

Tim, this is a very good opening for a debate around this.

Fine thread idea

 

I won't flatter myself to pretend to know that I've got the techniques bagged, so I will offer up some justification around what I've been up to.

 

I think the lack of training oportunities & associated literature, is partly what led me in to giving decompaction with a spade a go, so that we could see what is actualy going on underground.

 

The main reason of zoning the plate of that Chestnut, was to limit the amount of unknown damage we may have caused by going with a program of entire plate decompaction.

The idea now is to see what, if anything, happens over the next growing periods before deciding whether to go and finish the unspaded areas next year or perhaps 2012.

 

Although we were not getting down with a scope in between blastings, there did appear (as we were actually looking out for it) to be little if any perceivable visual evidence of ecto mycoors on the roots of the Chestnut.

 

I'm not saying there wasn't anything going on, but nothing to our keenish eyes.

Ofcourse this may have been down to the blasting, but we were taking time out and having a root around inbetween shots.

 

I suppose what would be a good idea would be to dig trial holes (across the plate) first, to try & extract mycoorhyzal material if at all present.

 

Maybe then send that off to Kew for analysis.

 

As most will probably realise, I'm/my team are a product of practice rather than full on theory.

That's just how I need to read things.

 

 

Btw, I'm guessing the ignorance remark wasn't full throttley aimed at me

 

 

.

[Xerxses]

Thanks Bundle! I will, as with many threads, follow this one closely...

 

I will meet up with one of Swedens (if not Europe) most experienced rootproblem and treerevitalisation experts in the end of the month...

Will speek to him about this and see if I can come back with some info.

 

I know nothing about this first hand, I have only heard about other peioples experiences but I´m keen to try some for myself. I have got a few trees that could do with a decompaction and vitalisation..

 

It would be nice to hear Lee Winger and BatiArbs opinions on this subject!

Edited November 12, 2010 by Xerxses

[Bundle 2]

Tim, this is a very good opening for a debate around this.

Fine thread idea

 

Btw, I'm guessing the ignorance remark wasn't full throttley aimed at me

 

David...I have some queries that Id like to put up that are the result of reading your posts and thread. I will do this when I have had the opportunity to gather my wits if thats ok!

Full marks to you, if that isn't too uncomfortably patronising.....It has been already remarked, good to see this work. That you fly by the seat of your pants in that it is tentatively exploratory and in full view of the public, and that the tree is of sentimental value only makes this more so.

Good to know that you still feel this way about how much you know however...Our attitudes are very much part of our willingness to engage and learn new stuff. And remember; science is about being right, but also about seeking to satisfy an enquiry, and this will often lead to the debunking of longheld beliefs maybe.

Keep challenging youself in this way. It makes it more interesting.

You are a prolific contributor to this site and I am certain this it is appreciated by many more folk than acknowledge it for whatever reason.

I hope that people will feel able to ask the stupid questions, they are not often as stupid as they think.

 

 

Lastly though David, if you feel the cap fits...wear it !

 

 

 

I will meet up with one of Swedens (if not Europe) most experienced rootproblem and treerevitalisation experts in the end of the month...

Will speek to him about this and see if I can come back with some info.

 

It would be nice to hear Lee Winger and BatiArbs opinions on this subject!

 

Thanks Xerses. I look forward to contributions to this thread.

Really though. I wish those in the know will feel able and willing to make comments as they see fit, your support is appreciated!

[Xerxses]

Thanks Monkey-D your input is very valuable! Firsthand experience is in my opinion the best. I appreciate that people who make a living out off these practises might be reluctant to reveal all their knowledge that has been obtained through experience.

 

It would be intresting to see some results on airspading, especailly after a few years....the one thing that would be the most intresting would be to se a decompaction after say five years, beeing examined with an airspade!

 

My collegue has been involved with several reconstructions of planting pits in urban areas. Street trees with small plantingpits in hard surface has been cleared of all soil and rebuilt with new porous "skeleton"-soil. The method has been to blast all the soil to break it up and then use vaccum-excavating to suck all the soil away. Big rocks to carry heavy weight of traffic has been added and then the space between the rocks has been filled with new soil...growing rate has been tremendous! Rootsystem has fully recovered and beyond!!! But this work has only been carried out in the worst conditions in citycentres, it would be intresting to hear about similar positive outcome from decompaction and trenching.

[Amelanchier]

The extent of actual mechanical damage by Airspade has not been rigorously examined - there are few papers out there that actually look to examine the impact of the procedure. What little there is seems to suggest (unsurprisingly?) that damage is species specific depending on root anantomy. For example;

 

Kosola, K, B. A. A. Workmaster, J. S. Busse and J. H. Gillman. 2007. Sampling damage to tree fine roots: Comparing air excavation and hydropneumatic elutriation. 2007. HortScience 42(3): 728-731.

 

Who find (taken from the abstract with my empahsis);

 

"Root damage was primarily due to loss of root tips. Although species varied in their susceptibility to root damage and whether air excavation caused more damage than elutriation, root diameter was not a good predictor of damage during sampling. Air excavation caused ≈26% greater damage to root samples of river birch and western redcedar than did elutriation. Both sampling methods caused equivalent root damage in all other species. Root anatomy influenced susceptibility to damage during sampling. Epifluorescence microscopy revealed a root hypodermis in all species except Amur corktree and western redcedar. Without the mechanical support of this suberized layer, the cortex of Amur corktree was easily stripped from the stele, leading to extensive damage by both sampling methods."

 

So lay off the airspade decompaction on the Thuja?

[Lee Winger]

I don't try and go too in-depth these days, does vertical mulching, radial trenching and soil decompacting with the terra tree/ terravent work and show significant results in stressed trees, yes and that's really all I'm concerned with!

 

Would I decompact and turn over an entire root zone with an Air-Spade NO WAY some do I don't, soil de-compaction IMO is best carried out in moderation. From my own experience the Air-Spade will very rarely physically sever fine roots, but I do believe it will dehydrate fine feeder roots. That's why I don't de-compact any more than 20% of a root zone/compacted area [with Air-Spade] The short term damage in my experience is far outweighed by the long term benefits of de-compaction. Feeder roots grow quickly IMO after de-compaction, hence the positive results.

 

My preferred methods of soil de-compaction these days are vertical mulching or de-compacting with the Terra Tree and mulching the root zone afterwards. If incorporating mulch isn't an option, I like to use soil conditioners/bio stimulants and compost teas, I rarely if ever use inorganic fertiliser or mycorrhizal inoculants these days, because with fertilisers we don't know the true effects long term. I have however in the past used weak fertiliser dilutions that have proved beneficial all be it short term so far! and as for mycorrhizae, I had a long chat with a mycologist some months ago, he specialises in mycorrhizae, and he like me is convinced trying to add off the shelf mycorr potions to mature trees is a waste of time, far better to try and make ideal conditions for the myccor that's present.

 

 

 

Anyway lets not forget the Air-Spade has many more uses than just de-compaction, I use it as a excavator for root pruning, inspection pits, root investigation etc etc. As for training, who has enough experience to put together a training package? I learn something new every time I use the Air-Spade.

 

If a training package is put together and no doubt somebody will, it will be a H&S money extracting jobby, IE do not point and blast your colleague wth Air-Spade, do not use Air-Spade under influence of 10 pints of Stella a spliff or after injecting smack, do not use Air-Spade for pest control purposes and blast bunnies and rats out of burrows, such training I'll pass up on..

Edited November 14, 2010 by Lee Winger

[Xerxses]

Cheers for the input!

Do any of you have before and after pictures?

I like pictures....

[Bundle 2]

Thanks Lee...Terra Tree is a terravent I assume? You have experience with this tool and clearly feel there are benefits to be had from the technique. Thanks for posting.

I will be visiting KEW soon . Doubt I will get the opportunity to pin specific enquiries on Tony Kirkham but at the risk of repeating myself...he did desist from terravent works for some reason or other.

Wise words also about the use of fertiliszers...

 

 

I was not aware that "elutriation" was a widely used technique. It sounds messy! It's bound to result in more physical damage- it introduces matter (H2O) to this process as far as I can understand. Not an immediately obvious control....

Thanks for posting that up Mr .S

 

This is a paper discussing the topic of compaction. I have not read it myself yet. Hope it proves informative!

The impact of soil compaction on soil aeration and.pdf

[Bundle 2]

It seems not all experiments are quite so well conceived. So far, recreating the effects of compaction is not as straightforward as it might seem!

Terravent:airspade.pdf

terravant soil amelieration.pdf

The impact of soil compaction on soil aeration and.pdf