There are many wonderful treatments for dying root systems. Mycorhizzae, NPK, aeration, fracturing, irrigation, etc.
When a Douglas-fir tree is dying a long and drawn-out death due to soil degeneration, I believe that "no-treatment" is the wise approach. Let the tree ride the decline spiral, hopefully the beetles will find it, it will turn brown, and choices will be made from that point.
Douglas-fir is just an example, one that I am the most familiar with. I am confident from my observations that it is fair to include pines, true firs, and hemlocks here.
Root death and soil death are inseparable. When soil compaction- or depletion- prohibit a root system from exploring for nutrients, the roots' zones of elongation slow down. Ubiquitous opportunistic parasites, including fungi in the genera Pythium, Rhizoctonia, Fusarium, Phytophthora, Armillaria, etc., are able to germinate and penetrate root tissue that is still unprotected by secondary anatomical and chemical defense structures and mechanisms (growth being primary.)
Root system stalls out, necrotic tissue accumulates, starch reserves are used up, the tree loses its hold upon the ground, and it blows over in an ill wind.
This is started by soil compaction and nutrient, oxygen, and water depletion. The "root nibbling" fungi mentioned above stall out opportunistic root growth. Older woody tissue deteriorates. Brown rot fungi jump right in if they are present. Soil arthropods macerate dying tissue.
Then someone adds NPK, irrigation, mycorrhizae, and stimulates adventious root growth. It is enough to keep the foliage alive and green, but to look at the periodic annual increment you need a hand lens to discern the years. And so there is no warning to the average observer when the tree tips.
There is no demonstrated method to restore dead, depleted, compacted soil around a large conifer. In my opinion, it is better to let such a tree die when it is giving the signals, or better yet, cut it down while it is relatively safe, and replant with an adaptive species.
That was sure long-winded. Your comments, please.

Reply to post by Peter Torres, on September 03, 1998 at 01:16:52:

I've asked this in other places, but has anyone studied soil injections of organic materials?

It seems you would get some aeration benefit, and seems less invasive than other meathods.

I realize this has little to do with you statement on Hazards, but I'm always curiouse.

Reply to post by John P Sanborn, on September 03, 1998 at 01:16:52:

John; Please describe "soil injections of organic materials" in adequate detail. Thank-you.

Reply to post by Peter Torres, on September 03, 1998 at 01:16:52:

A learned treatise, for sure! Actually, I agree and am often known to give last rites to trees when there are a thousand possible ways the client could spend more money and still lose the tree. Thanks for your clear presentation of the process.

Reply to post by Peter Torres, on September 03, 1998 at 01:16:52:

While I fully understand and appreciate Peter's perspective here, I can't agree with it.

I think there are some things that we can do to provide treatment of both the root system ills and the soil problems. The addition of microbial innoculum for instance is an excellent method of introducing a "decompaction" mechanism onto the site, as well as a series of organisms which may/will help to compete with or attack decay organisms.

I also believe that there are a few techniques available to us to address soil compaction issues mechanically (which do not contribute to compaction themselves) and they should be used.

The bottom line to my thoughts here is that I believe the client has called me onto the site to do what can be done, and I think I should do that in an effort to help the client save the tree. A callous approach, in my mind is not the way to go. At the same time, I respect what I believe Peter is refering to, in that so often clients are sold a bunch of ineffective treatment, which also isn't good.

If there is hope, which in our drier areas inland, there often is; I think we should take the few steps available to us to TRY in good faith.

Best regards,
KWK

Reply to post by Peter Torres, on September 03, 1998 at 20:21:02:

using a slury injected into the rhizosphpere (& beyond for future devlopment) usneing a pumper truck like many use in ferting. I realize a larger more durable pump (maserating?)would be needed and probe with a large orfice.

seems to me something like this would work good in amending the soil w/o causing damage to root systems, and causing the "potbound" effect found in auger holes.

is that clearer? guesse one could say it's like mudjacking around the trees, (w/o trying to raise grade tho).


jps

Reply to post by John P Sanborn, on September 03, 1998 at 20:44:09:

I get the basic idea, though it sounds impractical. Perhaps in very sandy soil at low but prolonged pressure, but it seems like hydraulic excavating would be needed first to create a place for the slurry to go.
By the way, "rhizosphere" refers to a very small soil interface around root material. You should say "root zone" instead. Peter

Reply to post by Kerry, on September 03, 1998 at 01:16:52:

Kerry; I do not know of any treatment for compacted soil within a large conifer root zone- neither mechanical nor microbial.
Rob Gross's hydraulic suction/replacement might work, or it might not. I don't see how pore space will benefit from this method.
Only soil micro- and macro-fauna can restore soil porosity. This takes a full human generation if the area is cordoned off.
If possible, and if you have the time and interest, please cite particular personal experiences or documentation that you are aware of that supports your position.
Personally, I believe that identification of large conifers that have gotten far down in the decline spiral- if there is a sensitive target- militates for R&R. Peter

Reply to post by Peter Torres, on September 12, 1998 at 12:49:45:

>By the way, "rhizosphere" refers to a very small soil interface around root
>material. You should say "root zone" instead. Peter

my understanding of the term was that it encluded the symbiotic biota (mycorizae et al) and since the mycilium of some fungi can spead several feet, the two are interchangeable.

Tho I agree with you, I should have used the latter, it's just my tendancy towards multisylabic utterances.

jps

Reply to post by Peter Torres, on September 08, 1998 at 00:24:07:

"Only soil micro- and macro-fauna can restore soil porosity. This takes a full human generation if the area is cordoned off. "

I think you may be underestimating soil life. We have been using PepTree products for about eight years now and have observed substantial reversals of adverse soil conditions, including remediation of petrochemical spills in three to five years time.

I think that the key to success in using microbes though; is to accent conditions which favor them...adequate moisture, optimum soil temperature, and addition of mulch/compost/leaf litter. Conditions favorable to beneficial microbes also requires the reduction of pesticide use (most derived from chlorine or flourine, pretty good antimicrobials) and excessively salty fertilizers (potassium chloride for instance)(ammonia makes a pretty good germicide too).

Much information is available from bioremediation of pollution web sites, if you are looking for documentation. We've been monitoring such, and believe results they are getting are consistant with what we are seeing in our work with trees.

A tree related web site resource would be http://www.planthealthcare.com/ and some of the information on the PepTree site at http://getmoreinfo.com/biocaps/

Best regards,
KWK

Reply to post by Kerry, on September 13, 1998 at 21:55:16:

Thank-you, Kerry, for the info. I will look at those web sites. I want you to realize that I am talking about soil compaction- the collapse of micropores and macropores. I will be looking for info on the amelioration of soil collapse on the web sites you mentioned. Peter

Reply to post by Kerry, on September 13, 1998 at 21:55:16:

Kerry; Thank-you for the web sites. I especially liked the Research Links page.
I maintain that nothing shown on these sites can de-compact soil. I agree with Thomas B. Randrup, who authored "Soil Compaction on Construction Sites", J. of Arboriculture, 23(5): Sept. 1997. I highly recommend this article for some basic soil compaction information.
Growing new trees in a prepared hole within a compacted soil does not have anything in common with compacting the soil in a mature root zone.
Today, I was informed by a construction manager that he was told to "aerate the soil" around a line of mature pin oaks adjacent to the project (well within the dripline.) While I appreciate the thought, I asked how the city arborist said to do that. Because if the arborist has an answer that works, I will be enlightened, and will post the answer here.

Reply to post by Peter Torres, on September 15, 1998 at 23:36:33:

Peter, there is a difference between "aerate the soil" and "relieve compaction". The first is possible, by simply creating channels iwthin the soil that will increase (however little) the exchange of gases, allowing oxygen to infiltrate the soil. As anoxyia is major root growth inhibitor, aeration may help even in compacted soils. Releiving soil compaction is another matter. Tilling of course is not practical with established trees, and further breaks down the structure of the soil. But while our efforts are not perfect, in many cases the trees do respond. Some methods work bettter than others.

It is generally acknowledged that increased coarse orgainc matter improves the soil, so any addition would seem beneficial. One of the main beneifts is that it creates an environment for other living organisms that further improve the environment. Dig a foot of soil in the middle of a lawn and another in a mulch bed, and count the earthworms. You'll probably find a difference.

My point is, if we shy away from everything because it doesn't rectify a problem completely, we will get nowhere. If all we can do is a partial job at best, then the best is all we can do. Just don't sell it as the final solution.

My recommendation is usually a combination of what some call "deep pore aeration" and mulching. Drill the holes, backfill with a loose organic soil, and then mulch the whole area. The result is usually better than either treatment alone.

Russ

Reply to post by Russ Carlson, on September 25, 1998 at 19:35:23:

Russ,

I've noticed when doing fert's and deep watering that even hard clay soils are loosened.

if doing this on a 2ft grid, from 3ft from base to several ft out of the drip line, wont this releave compacion significantly, and provide aeration?

also, I recomend to people that dont want to payme, use the Ross root feeder to deep water. I' looked into their instruction and there is no recomendation on amounts/duration of watering.

can significant root damage be done from one leaving one of these things running to long? say an hour or two? had a few of them ask, I don't think so but it's only suposition, wich i also tell them.

jps

Reply to post by John P Sanborn, on September 25, 1998 at 22:48:04:

John, I don't think you will really "relieve compaction" with pressure injection of liquids. It may improve aeration, though, as it forces channels in the soil and allows air to permeate the soil a bit more. Within the whle soil structure, though, all you have done is create channels. The larger blocks of the soil are still compacted. You haven't altered the particle distribution and density at all. There will be an improvement, and perhaps enough to make a difference for the tree, at least for a while. I also suspect (no data) that repeated treatments will continue to increase this effect, but only up to a point. Once channels are opened, they will silt up again naturally. Repeat treatments may only reopen previous channels. That may be beneficial, but also may not further improve things too much. I still think we cannot easily or quickly "reieve compaction" without rebuilding the soil structure on a particle level.

Re: long watering- Leaving a "root feeder" probe running for long periods probably won't affect most trees. However, some species are sensitive to too much water at certain times. The greater problem may be with soil drainage. A loose soil can suffer greater damage than a compacted one. A natural pressure will develop once the soil immediately around the probe is saturated. The water can't flow freely away from the injection point, and it will eventually equalize with the pressure of the hose (approx. 60 - 80 psi for most public supplies). Then the flow out of the probe is slower.

In loose soils, the force of the water can cause the soil to wash out around the probe, forcing some particles into a tighter pattern, effectively increasing compaction. The water will continue to flow outward if drainage is good. The result could be creation of small open pockets in the soil. This will allow the soil in the immediate area to dry out, and may effect root growth. This is probably a rare occurance, especially where the soil has much clay.

Russ

Reply to post by Peter Torres, on September 15, 1998 at 23:36:33:

Check out http://www.soilfoodweb.com/index.html.

Bacterial exudates stick soil particles together which helps to create voids. Fungal hyphae seperate soil particles and create vertical passage ways. Microbes are food to numerous species of bugs and worms who make passage ways. Bugs and worms are food for larger animals, including larger bugs and worms, who also make passage ways.

All of this activity improves both aeration and water flow.

Best regards,
KWK

Reply to post by Russ Carlson, on September 26, 1998 at 14:09:47:

>This will allow the soil in the immediate area to dry out, and may effect root growth. This is probably
>a rare occurance, especially where the soil has much clay.

This is what I've noticed, SE Wi being mostly clay, Ive told them to just water regularly in those areas

As for opening chanels, won't this enable root growth in these areaa wich in turn will, long term, help with soil structure?

Does anyone recomend the use of tap root perennials such as mustard, for aeration and vert muching as viniards do? I realize this wont work in a front yard, but beddings wild areas and construcion sites it can be mowed for green manure (viticulture again)

Last, do you have any thoughts on my quereies about slurry injections?

Reply to post by Russ Carlson, on September 25, 1998 at 19:35:23:

Russ; You wrote "My point is, if we shy away from everything because it doesn't rectify a problem completely, we will get nowhere. If all we can do is a partial job at best, then the best is all we can do. Just don't sell it as the final solution."
In many cases I would agree. To return to the initial posting, I argued that it is better to do nothing if you are creating a potentially dangerous condition: namely, creating a plethora of adventitious roots around a rotting root system belonging to a large conifer.
I would prefer that such a tree be cut down while it is still relatively safe. Failing that, I want them to be left alone to die in relative tranquility until bark beetles turn them brown.

Reply to post by Peter Torres, on September 25, 1998 at 22:48:04:

Peter, I agree with you last statement.... except the part about leaving it to die. If it can't be preserved for a reasonable period, and will become (or is) hazardous, there is no choice. It simply has to go.

the point I was making is that sometimes it is not wrong to treat the customer along with the tree. But if that becomes the case, you must be sure the tree will not be worse off for it, or that it is trying to overcome fatal problems or safety issues. You also have to know where to draw the line, and you have to be honest about what you are doing and why.

Reply to post by John S, on September 26, 1998 at 23:27:52:

Roots growing through the channelscreated by injection will "eventually" help soil structure, if everything else stays the same. But the woody roots of trees will likely live a long time, the more ephemeral roots won't make much difference. The channels will fill in with silt, and the level of compaction will usually revert somewhat as the open channels slump back into place. The time will depnd on soil structure and texture, compaction, rainfall, etc. The greater effect will come from the insertion holes to the surface. You need to remember that organic matter, such as growing roots, will not improve the aeration until the die and begin to decompose. Until then, the oxygen can't utilize that space.

Reply to post by Russ Carlson, on September 28, 1998 at 22:30:12:

Let's get philosophical. There are industry standards now for what constitutes the trailing edge of a hazardous tree. Therefor, courts of law and peers and expert witnesses will affirm that said tree was hazardous and should have been cut down. That does not mean that there was no choice. It is always an option to preserve a hazardous tree, unless the owner/manager is somehow forced to cut it down. I present a hazardous tree as such- and give the owner/manager the options; remove, shorten, live with it (calculated risk), and get more insurance for property damage/liability. See you Thursday.... Peter

Reply to post by Russ Carlson, on September 27, 1998 at 16:34:57:

>>You need to remember that organic matter,
>>such as growing roots, will not improve the
>>aeration until the die and begin to decompose.
>>Until then, the oxygen can't utilize that space

that is what I ment by "eventualy" the ephemeral roots that fill the channels.

if one is making regular "deep waterings" within/beyond the drip line should keep the channels open. We are talking about "relieving" soil compaction, reducing it not eliminating it. You seem to be talking about eliminating the compaction comletely.

the procedure is simple and inexpensive, seems to me there should be some cumulative effect.

jp

Reply to post by John S, on October 04, 1998 at 21:42:57:

Not really talking about reducing or relieving compaction, as much as aerating the soil. Compaction is a reduction of pore space, both in size and volume. The treatments we now have will not change that. Air and water injection, fracturing, etc., aerate the soil, but do not address the pore space issue directly. That part happens very slowly in most cases, by live organisms.

Water flowing through channels in the soil may actually cause them to close more rapidly, since the water may carry fine particles (silt and clay) that end up filling the channels.

I'm not disputing that opening channels helps- it does. We just need to be careful that we don't confuse aeration by channeling with actual change in soil compaction or bulk density and texture.

Russ

Reply to post by Russ Carlson, on October 06, 1998 at 16:36:37:

Got it, your arguement is that compaction is a microscopic event, the "hydro-aeration" workes on the macro level, only the worms (et al) moving in and out will releive the microcompaction that binds up the esential particles.

Reply to post by Peter Torres, on September 03, 1998 at 01:16:52:

I agree with Peter, I would like to add though that as arborist's we also contribute to a harmful public issue when we seek every option to preserve. Does the word "Sustainability" raise any concerns?
I do not find the ability to maintain a healthy urban canopy a reality, when infected Douglas Fir trees are left to stand in or near targets eventually within 2-3 years failing causing significant
damage. Does the homeowner or offended party replant trees? In most cases they have suffered and enormous loss, and will have little to do with re-planting.

Therefore, I believe I am not doing just to a larger picture of tree preservation by trying to save one severely infected tree.

Peter, tho your original was a bit "winded", it still is good to stir physiological thoughts.

Steve