Giant mulch rings...never seen one, and don't believe in them!

[yibida]

http://www.sgaonline.org.au/info_mulch_chunky_or_fine.html

Thanks Ekka, makes sense to me just gotta trade in the back yard 4inch chipper for a bigger one.

With the drought Ive a mind to use it though as opposed to prayin for rain.

 

[D Mc]

As to the size of mulch rings that will provide real benifit perhaps someone with more botanical knowledge could supply a link or reputable fact to determine where at least 75% of the trees roots are located. That distance from the trunk would give a realistic size to a mulch ring as a blueprint then it can be adjusted according to species, soil type, and location.

http://edis.ifas.ufl.edu/WO017

During tree root growth trials in Florida and New Jersey, excavation of root systems revealed that tree roots grew beyond the branch drip line for all six species tested, but the lateral extent was species dependent. Green ash roots, for instance, grew from the trunk 1.7 times further than the branch spread. Southern magnolia, on the other hand, had roots out to 3.8 times the dripline. On average, tree roots spread close to 3 times the spread of the branches, so that a tree with an 8-foot branch crown spread would have a 24-foot root spread diameter


Dave

 

[S Mc]

Been a long time since I was in landscaping and turf management (even went to school for that many moons ago) but we used to try to design natural areas for the trees with an island for mulch and usually pine strawed over it (in GA). We would try to create a nice large natural island for areas where there was a small grove of trees and rings around solitary trees in the turf areas. Trees in the large islands always seemed to do better than the solitary trees (especially the young ones) where we would typically only mulch maybe out to three feet. An added benefit (IMO) was there was less turf to manage and healthier trees overall. I also think the natural areas are more aesthetic looking and creates diversity.

Well said and good observations. The proof is in front of us...we just have to open our eyes to recognize it.

Sylvia

 

[S Mc]

I noticed what seems to be a deficiency in your reasoning. :monkey:

Do have any data, photographic and validated evidence to support your claims? Or is it another generalization?

In the picture you posted the undergrowth was ferns, I wonder what the redwood's root density comparison would be if we took a soil core and compared it to a location where there was no ferns and just mulch (on the indigenous forest floor that is).

What you are suggesting here is that an almost symbiotic relationship exists between species occupying the same soil area. If that's the case then it needs to be scientifically validated and added to this list perhaps (or one like it).

http://en.wikipedia.org/wiki/List_of_symbiotic_relationships

Gad, Ekka, you took my post away. I was going to say virtually the same thing.

A photo of redwoods and nitrogen-fixing ferns...the ultimate companion planting...check the mulch under those trees.

This thread is specific to turf and grass and the relative size of mulch rings. IMHO a small mulch ring, where it is better than nothing, is a mere physical protection for the trunk against lawn mowers and weedeaters. The small absorbing roots are out further (depending on the size and species of the tree). They grow, die and regrow along the main root and tip of that root. Again depending on the size and species of the tree, these absorbing roots can go out 2 to 3 times the canopy of the tree. Well, beyond the dripline.

This is why I so often say, "out to the dripline if possible". Because I realize it is not always possible, I am trying to recommend protection of as much of the nutrient-uptaking roots as I can.

Sylvia

 

[pdqdl]

Not from the lawn, from the lawn "technician"!

Lesco hort supply suggests you fertilize your centipede lawn 6 times a year. Scott's says, what, 5 or so?

pdqdl, obviously you recognize the benefit of grass that needs mow and blow as often as po$$ible but are you aware of the ill effects of forcing woody perennials to grow at this manufactured rate? A 50' diameter mulch ring will help protect the tree from whatever junk science is being performed on the lawn.

Great thread, by the way.

Well, I won't deny that claim at all. But that is not what all the giant mulch ring proponents are claiming. They usually claim that they are eliminating competition from the turfgrass roots.

 

[lh3]

Are my questions invalid to the topic? I am not an a professional arborist, but would still like to learn a little more about what is supposed to be helping my trees physically or chemically.

 

[pdqdl]

Really, were you awake? If you indeed have a BS in biology, obviously not soil biology, but learned about all the other plants and animals of the world, you already know the answer.

I'm posting a link that took me 30 seconds to find on a google search.

http://www.mortonarb.org/images/stories/pdf/our_work/Tree_vs_Lawn.pdf

The information on the benefits trees derive from mulch abounds. But you will not see this unless you open up you mind.

Dave

That was a nice, well written article in support of your claims. I am sure that there is a great deal of merit to the facts that it presents. But it doesn't meet my standard of evidence. I expect something more scholarly that shows actual research, methodology, and purports to have a more objective viewpoint. The article you cited is just that: just an article. It's not what I would call documentation.

 

[outofmytree]

http://edis.ifas.ufl.edu/WO017

During tree root growth trials in Florida and New Jersey, excavation of root systems revealed that tree roots grew beyond the branch drip line for all six species tested, but the lateral extent was species dependent. Green ash roots, for instance, grew from the trunk 1.7 times further than the branch spread. Southern magnolia, on the other hand, had roots out to 3.8 times the dripline. On average, tree roots spread close to 3 times the spread of the branches, so that a tree with an 8-foot branch crown spread would have a 24-foot root spread diameter


Dave

Thanks for the link Dave. Gonna have to read more of this as I always thought the drip line was the approximate extent of the root system of most trees. Doh!

 

[pdqdl]

I'm sorta agreeing with you, partially: mulching to the dripline is overkill.

So I should document research, but you don't have to?

refute my opinions please;

Turf an artificially maintained environment that is close to a monoculture. Maybe three genus of grass grown with a mix of species.

Turf management removes the nutrient cycle from the urban/exurban environment; if we mulch the grass, it still does not have much nutrient value to it. Most people do not want the annual leaf fall to be mulched in. Not only doe this starve the environment of minor and trace minerals and elements, it makes for an organic poor topsoil. How many people have their lawns top-dressed on a regular basis?

Low organic soils lack a diversity of beneficial macro and micro-biota.

We could go on...

Thanks for the support. You may not be aware of some of the more current trends in lawn maintenance.

Since the advent of laws preventing yard waste in landfills, lawns are rarely bagged anymore, although it certainly occurs. All but one of my customers have been converted to mulching.

Leaf accumulations are now being handled (only by a few, more astute lawn service operators) by mulch mowing the leaves in place. You blow all the leaves out from under the bushes (already mulched areas!) and then circle cut the lawn until the leaves are in a pile in the center. Then mow over it until they turn to dust. Take your blower and spread the remnants over the lawn. This has several advantages: it cuts WAY down on the labor to remove the leaves, it eliminates the need for disposal, and it returns the organic material to the earth from which it came.

Follow that with lawn aeration, and you have genuine topsoil re-generation, better and much faster than nature can provide. Heavy clay soils become modified in the top 3"-6" with organic materials and the lawn is dramatically improved, as well as having lowered watering requirements.

So a lawn service can actually return more of their yard waste to the soil than a tree service can. I don't know of too many situations where the tree gets chipped in place and left on the ground it came from. My business does that pretty often, but only in rough terrain situations where the quality of appearance is not important. Even then, we do it as a means to reduce expense or provide erosion control for the bare ground.

 

[pdqdl]

http://www.sgaonline.org.au/info_mulch_chunky_or_fine.html

Good article Ekka!

Who would have thought that fine mulch sucked water from the soil? I still question the evaporation rate of the fine mulch. I wonder what controls they had for long term evaporation rate?

I would prefer to see moisture content readings (and temperature recordings as well) at various depths under bare ground and the different types of mulch. In my opinion, that would be a better way of comparing the relative value of the moisture retention qualities of different types of mulch.

 

[pdqdl]

Do you volunteer the information concerning the residual of a chemical with a class 3 Acute Hazard Warning rating (Dimension with turf fert) as they lounge and frolick in this luscious weed free grass?
...

Huh? Here is the label (below) for Dimension (without fertilizer). Precautionary statements are standard issue, pretty much the same as everything else.


No mention of a "class 3 Acute Hazard Warning". I suspect that warning comes from someone other than the government. I never heard of ANY "classes" of warnings concerning chemical usage. It is not part of the terminology endorsed by the EPA for certified applicators.

Missouri law REQUIRES that every application include the specific EPA registration numbers of every product used, whether done to lawn or trees. So technically, yes! Every customer knows what is put on their lawn.

On a more practical basis, they are completely ignorant, and seldom check anything out for themselves. If they were motivated in that direction, they would probably be doing the work themselves.

 

[ddhlakebound]

TBut it doesn't meet my standard of evidence.

It's not what I would call documentation.

Wouldn't it be easier just to say "I choose to disbelieve reality and substitute my own."?

The control conditions you seem to require for scientific testing are pretty difficult to attain over a large sample through time in nature. Just too many variables to account for. That DOES NOT mean that the evidence we have available is discardable.

It's simple, and it's been proven.

Proper organic mulching provides multitudes of benefits to trees over allowing them to compete with turf. The larger the area of mulch, the greater the benefit.

We all know that very few homeowners will follow the advice to mulch all the way out to the dripline, but if they know that's the target area, they are more likely to mulch a small to moderate area, which will still provide the tree some benefits.

The evidence I'd like to see is regarding windthrows and mulching. How many trees could have remained standing if they'd had just a bit more mass to their root system, which mulching would have helped provide?

 

[pdqdl]

http://edis.ifas.ufl.edu/WO017

During tree root growth trials in Florida and New Jersey, excavation of root systems revealed that tree roots grew beyond the branch drip line for all six species tested, but the lateral extent was species dependent. Green ash roots, for instance, grew from the trunk 1.7 times further than the branch spread. Southern magnolia, on the other hand, had roots out to 3.8 times the dripline. On average, tree roots spread close to 3 times the spread of the branches, so that a tree with an 8-foot branch crown spread would have a 24-foot root spread diameter


Dave

I'm not sure how this legitimate documentation supports the cause of giant mulch rings. I have known for many years that tree roots extend far beyond the dripline. Haven't we all read how Dutch Elm disease was spread from tree to tree by interconnecting roots, far away from each other?

Even if you take figures from the smallest diameter root zone quoted (1.7), the surface area of the root zone under the entire dripline is only 35% of the entire root zone . At 3.8 times the dripline, your giant mulch ring is covering only 7% of the root zone!

Are you telling me that those poor magnolia trees are loosing the battle for water and nutrients with the turfgrass, and you are only going to give them a 7% leg up on the competition? Are these the same poor trees that got blown over in the hurricane study cited previously?

So why do you suppose these trees have this giant root zone? It is because they CAN. It is because the lawn has very little to say about where the tree sticks it's roots. The trees put out as many roots as they can because they have a giant need for water, less so for nutrients.

Almost nothing can stop tree roots, if you give them enough time. We all know how they displace sidewalks, curbs, and streets. In southern Missouri, there is a cave with tree roots coming into the roof of the cavern 160' underground!

Please don't take these arguments as a claim that trees are indestructible. The trees have developed this impressive rooting capability because it is so important to their existence. It is why protection of the root zone is so important. From people, from chemicals, from soil compaction, perhaps...but not from the grass. Just look rationally at your own evidence.

So for, no one has shown me how turfgrass is killing off the trees. Your own evidence shows that a mulch ring to the dripline actually provides very little protection (on a area-related mathematical basis) from that killer turfgrass. Damn that bluegrass and fescue, always choking those poor trees to death!

 

[Ed Roland]

Huh? Here is the label (below) for Dimension (without fertilizer). Precautionary statements are standard issue, pretty much the same as everything else.


No mention of a "class 3 Acute Hazard Warning". I suspect that warning comes from someone other than the government. I never heard of ANY "classes" of warnings concerning chemical usage. It is not part of the terminology endorsed by the EPA for certified applicators.

Missouri law REQUIRES that every application include the specific EPA registration numbers of every product used, whether done to lawn or trees. So technically, yes! Every customer knows what is put on their lawn.

On a more practical basis, they are completely ignorant, and seldom check anything out for themselves. If they were motivated in that direction, they would probably be doing the work themselves.

The Acute Hazard Warning Label on Formulated pesticide products (which usually include inert ingredients) are required to carry an acute toxicity rating by the U.S. EPA which is reflected in the warning label on the pesticide container. The U.S. EPA gives a warning label of Category 1 to the most acutely toxic pesticide products and Category 4 to the least acutely toxic pesticide products.

PAN Pesticides Database @ http://www.pesticideinfo.org/Detail_Product.jsp?REG_NR=06271900487&DIST_NR=062719

Product Name: Dimension turf herbicide

Acute Hazard Warning Label > 2 Warning

Citation: Kegley, S.E., Hill, B.R., Orme S., Choi A.H., PAN Pesticide Database, Pesticide Action Network, North America (San Francisco, CA, 2009), http:www.pesticideinfo.org.
© 2000-2009 Pesticide Action Network, North America. All rights reserved.

So, actually dimension turf fungicide carries a "warning" instead of "caution" acute toxicity rating. This indicates its pretty nasty stuff. The point is that i would rather lounge in the tree mulch than on your perfect lawn.

Herbicides, fungicides, insecticides and 5 fertilizations a year to maintain the grass monoculture. The tree roots unfortunately are intertwined throughout the same space within the soil as the grass roots. How can you dump all this stuff on the lawn and not effect the tree? I support mulch all the way to the drip and beyond for many reasons not least of which is to try and separate lawn care from tree care.

 

[outofmytree]

The Acute Hazard Warning Label on Formulated pesticide products (which usually include inert ingredients) are required to carry an acute toxicity rating by the U.S. EPA which is reflected in the warning label on the pesticide container. The U.S. EPA gives a warning label of Category 1 to the most acutely toxic pesticide products and Category 4 to the least acutely toxic pesticide products.

PAN Pesticides Database @ http://www.pesticideinfo.org/Detail_Product.jsp?REG_NR=06271900487&DIST_NR=062719

Product Name: Dimension turf herbicide

Acute Hazard Warning Label > 2 Warning

Citation: Kegley, S.E., Hill, B.R., Orme S., Choi A.H., PAN Pesticide Database, Pesticide Action Network, North America (San Francisco, CA, 2009), http:www.pesticideinfo.org.
© 2000-2009 Pesticide Action Network, North America. All rights reserved.

So, actually dimension turf fungicide carries a "warning" instead of "caution" acute toxicity rating. This indicates its pretty nasty stuff. The point is that i would rather lounge in the tree mulch than on your perfect lawn.

Herbicides, fungicides, insecticides and 5 fertilizations a year to maintain the grass monoculture. The tree roots unfortunately are intertwined throughout the same space within the soil as the grass roots. How can you dump all this stuff on the lawn and not effect the tree? I support mulch all the way to the drip and beyond for many reasons not least of which is to try and separate lawn care from tree care.

Dithiopyr is a soil residual herbicide used commonly in grain farming. The risk to the public associated with the use of this herbicide in a domsetic lawn when it is correctly applied is minimal at best.

Whereas I agree that it is important to balance out the use of chemicals in all situations I think focussing on this proven herbicide is a storm in a tea cup. I should imagine that over fertilization of lawns by both "lawnies" and the public is a far greater risk to the tree and people. Ever wiped sweat off your forehead after handling anything with Phosphor in it? Ouch. Don't inhale the dust either. Double ouch.

 

[pdqdl]

The Acute Hazard Warning Label on Formulated pesticide products (which usually include inert ingredients) are required to carry an acute toxicity rating by the U.S. EPA which is reflected in the warning label on the pesticide container. The U.S. EPA gives a warning label of Category 1 to the most acutely toxic pesticide products and Category 4 to the least acutely toxic pesticide products.

PAN Pesticides Database @ http://www.pesticideinfo.org/Detail_Product.jsp?REG_NR=06271900487&DIST_NR=062719

Product Name: Dimension turf herbicide

Acute Hazard Warning Label > 2 Warning

...
So, actually dimension turf fungicide carries a "warning" instead of "caution" acute toxicity rating. This indicates its pretty nasty stuff. The point is that i would rather lounge in the tree mulch than on your perfect lawn.

...

Sorry woodweasel, I don't think you quite understand the terminology. "Acute Hazard" refers to whatever hazard a product might have on a short term or "acute" exposure. An entirely different consideration is "Chronic Hazard", which means the hazard from exposure over a long period of time. Very often people confuse the word "acute" for meaning severe, or extreme; when in fact it has a completely different meaning.

This might help you understand: http://en.wikipedia.org/wiki/Acute_toxicity

I gave you the full, unedited document required by the EPA, and it does not include a single occurrence of the word "acute". Only two uses of the word "category" and neither of those are followed by a number. I don't know everything about what the EPA does, but that terminology is not any part of a product label.

"Warning" and "Caution" are special buzzwords used on a product label that define what Personal Protective Equipment the certified applicator must wear while handling the product. The goal of the EPA is to simplify the education process for the applicators: see "Warning" or "Caution", and you know what to wear.

I am very familiar with the PAN database. They are extensively published, cited, and crosslinked. Unfortunately, they are neither a branch of the government, nor are they impartial in their assessments. Their unstated mission seems to be the reduction or elimination of all pesticides. But I really don't see where you are calling Dimension bad stuff to be around. If it isn't on the PAN database as a "Bad Actor", you can bet that it is pretty benign. I hold their database in pretty low regard, as I have seen their opinions on a number of excellent products with no adverse ecological effects.

Here is a screen shot from THEIR webpage. Please notice that it is listed in the column of "acute toxicity" as SLIGHT, which is the lowest category of risk that they assign.

********************************************************************

By the way, Dimension is an excellent pre-emergent. I haven't used any for several years, mostly because I just don't need to. A bit pricey, it probably leads to a reduction in the overall use of herbicides in a lawn, because it is both a pre- and post-emergent herbicide. By using Dimension, you eliminate the need for MSMA, a decades old popular solution for crabgrass. MonoSodium Methane ARSENATE.

Which of the two chemicals would you rather have on your yard?

 

[computeruser]

One aspect not covered is that mulching around the tree is theoretically an attempt to provide something like the leafy and woody detritus normally found in forest habitat. It's known that urban and suburban trees with maintained and raked lawn right up to the trunk suffer chronic starvation, the human desire for "cleanliness" and an orderly yard puts the tree at a disadvantage. All I know is I hate seeing mulch volcanoes banked up over the root flare, the mulching strategy has gone haywire in current landscaping practices.
-moss

100% agreed, based upon research and experience. In a couple parts of the yard where artificial conditions were needlessly pursued by the previous owner of my home, the removal of offending competition - grass, non-native ivy - and the addition of mulch (coarse oak and ash wood chips, shredded oak leaves, a hint of grass clippings) has markedly improved the visible health of a couple of my large oaks previously in obvious visible decline. The tree in one spot is stuck behind a garage, adjacent to a patio, within 15' of my house, and is bounded not 10' away by my neighbor's garage and driveway. It is a twin-trunk white oak, 30" diameter stems and 48"+dbh.

Digging a shovelful of soil in this one test area previously produced nothing but a clay-like glob of soil when wet, and a mudbrick when dry. After three years, that same shovel of soil produces many dozens of earthworms and other visible soil life (to say nothing for the invisible soil life), obvious fungal mycelia in the mulch layer, and most interesting of all is the fact that the soil microorganisms are able to consume (as in convert 100% to something other than shredded wood) an entire two cubic yards of shredded red oak mulch per year over an area that is 15' x 40'! The soil no longer turns into a lifeless mudbrick, and soil moisture is moderated much better. Just like in the forest. The tree at issue stabilized its decline after year number two and has definitely rebounded this year.

I would add the caveat that annual mulch additions, especially of the commercial twice ground, can interlock to the point of becoming hydrophobic. I've seen mound plantings that are bone dry under the mulch, even though there is a torrential downpour flooding the yard.

I observed this all the time when I used to dabble in landscaping in my youth. Common sense would suggest that it takes a lot of water to saturate, much less penetrate, six inches of a substance that bears a strong resemblance to sawdust. But hey, at least the weed seeds aren't germinating, right? Heck, I once had a "pro" explain to me that the idea was to trap the water from the spring snow melt under the mulch, as that water was enough to keep the landscape going all year if evaporation could be prevented by a 6-10" layer of largely impermeable mulch...

From an intuitive level, I like the idea of mulch sandwiching: every time mulch is renewed a layer of true compost is added first.

Anecdotal experience shows this to be profoundly helpful. Even incomplete, unfinished compost makes a superb layering material. Again, based on my at-home test beds, using a sheet composting or lasagna gardening approach to mulching tends to lead to a more rapid improvement in obvious signs of soil fertility than the application of a shredded wood mulch layer alone. Using the presence of earthworms (adults and cocoons), the speed at which partially buried sticks begin to colonize with mycelia, and anecdotal observations of plants growing in the areas, it appears that layering makes a great deal of difference to soil quality and, by extension, improves the likelihood of optimal plant health under the conditions.

I suspect that a similar result could be achieved on a commercial scale by pre-spraying the area to be mulched with compost tea and following up by spraying the surface of the mulch after it is dispersed.

I think it was Russ Carlson, he did a survey of his yard and found the macrobiota count eightfold higher in soil under the mulch vs a few feet away in the turf.

This has been suggested and/or confirmed by a number of sources. The level of fungal activity that trees prefer, in particular, tends to occur in mulched areas (shredded wood, leaves, etc.) and tends to be difficult to create or maintain in the presence of turf grass.

My point is real simple: I don't see any benefit to the HUGE mulch rings so often recommended by some here at ArboristSite. I can show you many threads where someone mentions a tree problem, and the most often recommended solution is to "mulch to the dripline".

I still have not heard a compelling argument for this practice, although I certainly will concede that a native woodland setting is self-mulching by default, as the grass has died off beneath the trees.

Benefit or not, it is rarely practical to put a 40' diameter mulch ring on a standard residential lot. Yet it gets suggested the same way that most every small engine problem diagnosis begins with the suggestion that one try a new spark plug. I'd be more interested to know what the homeowner is doing in terms of yard/lawn maintenance, fertilization, irrigation, and what the existing soil composition and soil grade is like. Because you can have a full-diameter mulch ring, but it won't matter worth a damn if you're throwing salt-based fertilizers all over your lawn and yard, providing the trees nutrients they may not need in a form they don't want, and killing off the essential microbial and fungal networks in the soil..

As someone mentioned earlier, good thread. opcorn:

I wonder if anyone has performed documented trials on mulching and not mulching trees in a controlled environment during establishment.

I'm sure it has - anyone have good links to research on this?

Hydrophobic layers of mulch developing are a concern if mulch layers are non permeable to start with (very fine mulch seems to develop this problem). Coarse mulch doesn't seem to do the job as well though as weed growth takes a stand readily.

True, but you can get away with a thicker layer of mulch with the really coarse stuff without undue compaction or reducing air/water permeability. 2" of fine stuff might be too much, but 3-4" of chunky stuff fresh out of the chipper will still allow lots of air and inhibit weed growth very nicely, in my experience.

If mulch is applied in a green state and not composted correctly fungal growth develops and adds to a hydrophobic development within layers and the mulch becomes biscuit like over time.

Yes, but this only seems to create a problem with the very fine stuff. Shredded or chipper-chunks seldom seem to suffer from this problem, again based upon my non-professional experience. It can be mitigated somewhat by either applying the mulch over biologically active soil, a layer of compost, or by applying a microbially-biased compost tea mix to the mulch after it has been spread. You will still see the development of mycelia with the larger chunks of wood mulch, but the mycelia will tend to be longer and thicker strands, instead of the denser stuff that forms a fungal pancake layer in the finely shredded mulch. Different fungus will eventually bloom, too.

I have also read somewhere (sorry not sure of reference) that nitrogen draw down during composting robs the tree / shrub / plant as opposed to sustaining and fixing nitrogen when fresh mulch is used over long periods.

I've read this in a number of books and articles, and it seems correct on a common-sense level. Some reports/research suggest otherwise, though. In any case, I think that this problem, if it is one, is at its worst with finely shredded stuff applied over biologically inactive soil. In the couple test spots in my yard (and now the neighbor's yard, where I'm expanding my "research"), the creation of biological activity in the soil tends to lead to conditions where the mulch is largely consumed within 2 years of application, and a layer of biologically active top soil develops. Subsequent applications of mulches are consumed quickly. I have to believe that the creation of a rich mix of fungal and microbial activity in the top couple inches of soil is far more important to the tree/shrub/plant's long-term well-being than leaving the soil nitrogen alone by not mulching or "mulching" with an inorganic substance.

If one is really concerned about keeping available nitrogen levels up, it would seem that a dusting of alfalfa meal (or a shovelful of alfalfa pellets) or some similar substance could be put down prior to the application of the mulch. The alfalfa meal is a good source of nitrogen that microbes can easily and rapidly access, and it's cheap and readily available, too.

That said a mixture of a broad spectrum of components that are composted, ie.. leaves, twigs, wood, bark, fruit, etc.. in mulch seems to work better for me rather than an aesthetic one containing one ingredient.

Absolutely believe that. But if aesthetics are required, putting a layer of this broad-spectrum stuff beneath the finish layer of mulch will produce results that appear to be similar to using this mix alone or to applying a layer of finished compost prior to mulching with a single-ingredient mulch. Even a light dusting of shredded fall leaves and grass (as would accumulate in the mower bag when doing a final cut/bag of the lawn in the fall) would put a valuable mix of material down to give the soil and mulch a good jump in the spring.

 

[Ed Roland]

Sorry woodweasel, I don't think you quite understand the terminology. "Acute Hazard" refers to whatever hazard a product might have on a short term or "acute" exposure. An entirely different consideration is "Chronic Hazard", which means the hazard from exposure over a long period of time. Very often people confuse the word "acute" for meaning severe, or extreme; when in fact it has a completely different meaning.

This might help you understand: http://en.wikipedia.org/wiki/Acute_toxicity

I gave you the full, unedited document required by the EPA, and it does not include a single occurrence of the word "acute". Only two uses of the word "category" and neither of those are followed by a number. I don't know everything about what the EPA does, but that terminology is not any part of a product label.

"Warning" and "Caution" are special buzzwords used on a product label that define what Personal Protective Equipment the certified applicator must wear while handling the product. The goal of the EPA is to simplify the education process for the applicators: see "Warning" or "Caution", and you know what to wear.

Which of the two chemicals would you rather have on your yard?

I hate to divert us off topic with this side bar about chemicals but i did want to respond.

Sometimes I stick my foot in my mouth, too, so i will be gentle. You seem to have looked up the word "acute" and made some assumptions about my use of the phrase "acute hazard warning label".

Lets go right to the source. Here is what the EPA says "The acute oral, acute dermal and acute inhalation studies evaluate systemic toxicity via the designated routes of exposure." and then guess what... they assign a signal word. Making my use of the phrase "Acute Hazard Warning Label > 2 Warning" completely accurate concerning Dimension turf herbicide.

Here is the paragraph in its entirety taken from the EPA's Label Reveiw Manual. Chapter 7.

"ACUTE TOXICITY DATA. The Signal Word, Hazards to Humans and Domestic Animals, Personal Protective Equipment (non-WPS) and First Aid statements are typically determined by the results of the six acute toxicity studies performed with the product formulation. The acute oral, acute dermal and acute inhalation studies evaluate systemic toxicity via the designated routes of exposure."
-United States Environmental Office of Prevention, Pesticides EPA 735-B-03-001 Protection Agency & Toxic Substances (7506C) August 2003 Label Review Manual 3rd Edition

I hope this helped clear up your confusion about the EPAs use of the word "Acute" and how signal words are determined.

Now, lets get back to mulch vs lawn.

 

[treeseer]

I'm sure it has - anyone have good links to research on this?

http://auf.isa-arbor.com/search.asp

just type "mulch turf" or variations. Everyone is an expert when they know ho wto search the ISA journal site.

 

[pdqdl]

...Now, lets get back to mulch vs lawn.

Ok.