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

[pdqdl]

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.

Nice link treeseer! I am not familiar with that one. In fact, I used the "mulch turf" phrase you suggested and got only one response, and IT WAS A DANDY !

From the following very scholarly document comes the following quote: "Because of greater morning stomatal conductance, daily water use was greater for plants over mulch when compared to plants over turf and bare soil."

WOW ! Who would have thought that planting grass under woody plants would lead to a net REDUCTION in water loss for the poor afflicted plants being choked off by those evil monocots!

Check it out for yourself: http://auf.isa-arbor.com/request.asp?JournalID=1&ArticleID=2814&Type=2

I may yet get some of you super-mulchers to come around to my side!

(sadly, a closer read of this article reveals that very few genuine conclusions can be drawn from this article regarding the effects of mulch vs lawn on trees: the plants tested were containerized, they were being tested under water saturation conditions, and they did not attempt to evaluate the long term health of the plants being tested. In fact, at the conclusion of the article, the authors really draw no meaningful conclusions except to compare the relative rates of transpiration of the different bushes tested. The article does a splendid job of demonstrating that turf has many beneficial attributes that contribute to the well being of woody plants; a concept not previously introduced in this thread)

 

[M.D. Vaden]

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 link posted went beyond turf.

In short, trees can have turf beneath if desired, and maintenance can be tailored to meet the needs of that situation.

Likewise trees can be grown without turf beneath.

Hence, it's not an all or nothing issue like the .pdf article that was posted.

In this trade, we need to know how to to both, to be of some cultural value to a community's needs for the broad range of landscape design needs.

 

[Toddppm]

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?

I'd like to see this too. I've seen just as many windthrows in mulched tree beds as not. Does it make any difference at all? Maybe in richly mulched beds the roots don't have to get as big or long to reach the nutrients they need and aren't as well anchored?

 

[yibida]

Site Prep

I'd like to see this too. I've seen just as many windthrows in mulched tree beds as not. Does it make any difference at all? Maybe in richly mulched beds the roots don't have to get as big or long to reach the nutrients they need and aren't as well anchored?

Wouldn't site prep. such as cultivation / deep cross ripping of a soil profile have an effect on root system establishment in conjunction with mulch after planting?

 

[Toddppm]

Should I would think but we rarely do any more than strip the grass or weeds from a site before we make a new mulch bed unless a grade change is needed.

 

[pdqdl]

Ok guys. Lets keep it nice.

Hmmm. No one seems to have taken up the gauntlet since I posted the note about turfgrass reducing water consumption in trees more than mulch.

For those of you who didn't get the jist of the article, or haven't taken the time to read it, it went like this:

The surface beneath a tree does more than cover the ground. It affects the air above it. Mulch, due to it's good insulating properties, causes cooler earth and retained moisture in the ground only. It also reflects more heat upwards than bare dirt, and causes the air above the plants to be drier since there is less evaporation from the earth. Try to keep in mind that the trees live as much in the air as they do in the ground!

Grass, because it absorbs sunlight, allows more heat to reach the earth. It also transpires water into the air, which benefits the tree as well. Much less heat is reflected upward, and so the tree has cooler leaf temperatures and is in an atmosphere of higher humidity. These are benefits that have not previously been considered in this thread.

I think it goes without saying that a forest has little sunlight hitting the ground, so any comparisons of forest/natural mulch with turfgrass are not really valid.

So guys, where are the lawn bashers now?
(Still thinking about it I hope!)

 

[outofmytree]

Nice link treeseer! I am not familiar with that one. In fact, I used the "mulch turf" phrase you suggested and got only one response, and IT WAS A DANDY !

From the following very scholarly document comes the following quote: "Because of greater morning stomatal conductance, daily water use was greater for plants over mulch when compared to plants over turf and bare soil."

WOW ! Who would have thought that planting grass under woody plants would lead to a net REDUCTION in water loss for the poor afflicted plants being choked off by those evil monocots!

Check it out for yourself: http://auf.isa-arbor.com/request.asp?JournalID=1&ArticleID=2814&Type=2

I may yet get some of you super-mulchers to come around to my side!

(sadly, a closer read of this article reveals that very few genuine conclusions can be drawn from this article regarding the effects of mulch vs lawn on trees: the plants tested were containerized, they were being tested under water saturation conditions, and they did not attempt to evaluate the long term health of the plants being tested. In fact, at the conclusion of the article, the authors really draw no meaningful conclusions except to compare the relative rates of transpiration of the different bushes tested. The article does a splendid job of demonstrating that turf has many beneficial attributes that contribute to the well being of woody plants; a concept not previously introduced in this thread)

Ditto Treeseer, great link thanks for the info.

Pdqdl I read the information and although I see what your aiming at regarding the resultant water loss from the shrubs there is no mention of the water loss from the turf but the study clearly says that the temperature difference between turf and mulch is generated through transpiration via the grass leaves. This loss of water via the turf MAY balance out the difference in the shrubs and of course the study made no mention of the consumption of nutrients the turf would logically require.

It is worth noting that the soil temperature flux, (I take this to mean the variation in soil temperature throughout the day), was dramatically different under mulch compared to turf. I would like to know whether this more stable enviroment has some positive benefit to the development of useful organisms like mychorrizae.

More input from knowledgeable people required please.

Something else that occurred to me whilst reading the article was the stark variation in microclimate at .3m compared with very little variation at 2m. This means despite the obvious cooling effect of turf compared to mulch at near ground level, (you walk across either with bare feet at noon!) at the height most ornamental tree branches begin there is little benefit to the tree.

It seems the article does little to promote the benifits of turf compared to mulch when you consider all the information.

I still like a nice green lawn though....

 

[pdqdl]

Like most articles found in that journal, it uses way more arcane techno-speak than is necessary, much too much time describing the methodology, and the conclusions are...inconclusive.

You are right about the microclimate observation, especially about humidity issued. I suspect long wave radiation (infrared) doesn't care about "microclimate" except that it will vary as the inverse of the squared distance: double the distance from the source, and it will have 1/4th the intensity. So yes, the tree branches will be much safer than the shrubs beneath.

Keep in mind, the experiment was only attempting to relate the effect of different surfaces on the plants above them. So they did everything possible to isolate other factors OUT of the equation. This makes it impractical to apply real world scenarios to the date obtained from the experiment.

It's still great to see turf fare well against the mulch.

 

[Ed Roland]

It's still great to see turf fare well against the mulch.

Whats the score. It would be interesting to know what you have found compelling so far.

 

[tree md]

It would seem to me that reduced water consumption in trees over turf would also reduce the tree's potential, unlike trees over mulch where there is more moisture to be consumed and less chance for soil compaction. Just as trees in moister climates (PNW Redwoods or Cottonwoods in river draws of the MW) reach for the sky whereas trees in more arid climates (Oklahoma and Texas) are dwarfed in comparison. But I am no scientist.

Personally, I prefer landscapes with unique natural areas where there are a variety of trees and plants over barren, golf course manicured lots in neighborhoods where every lawn is a carbon copy of the one next to it. I imagine I would prefer the latter if I were into lawn maintenance but the former is more aesthetic looking to me and is better for my business model.

 

[John Paul Sanborn]

Like most articles found in that journal, it uses way more arcane techno-speak than is necessary, much too much time describing the methodology, and the conclusions are...inconclusive.

These are peer reviewed papers, so all the technical stuff is needed. I read the abstracts; then skim the rest.

You are right about the microclimate observation, especially about humidity issued.....Keep in mind, the experiment was only attempting to relate the effect of different surfaces on the plants above them.

Sounds like this is for new plantings and healing in; I cannot see these effects affecting the environment over 10ft above the ground.

As for the warmer soil, that is a benefit of the mulch. Betula is a good example, the borer susceptible species have a greater incidence of infestation when they have warm rootplates. Photo surveys around Madison Wisconsin, done by UW Madison a number of years ago, found that the southwest portions of hills had the greatest dieback, whereas the norther exposures were the healthiest.

 

[D Mc]

I am posting this link in the hopes of reaching some of you on the importance of what's happening beneath the tree in the living soil. This article reads well and describes the complexities and delicate balances that many people are unaware of. The associations formed beneath turf and trees are different.

I was going to highlight key portions that I felt deserved focus that pertained to the topic of this thread, but found it to have too much good information to only highlight those key points. I will, however, post the last paragraph which sums it up nicely. But please, take the time to read this link in its entirety.

http://www.treedictionary.com/DICT2003/shigo/RHIZO.html

"I believe there is a way to decrease the potential starvation problem. In forests, more wood should be left on the ground, and in cities, more composted wood and leaves should be added in correct quantities to the soil about the base of trees. Incorrect treatments of pruning, watering, planting and fertilizing should be corrected, because they often start the pumps to wobble. If these simple adjustments can be made, rhizosphere starvation will decrease and our trees will lead healthier and longer lives."




It is important to also note that current research has determined that fertilization and application of chemicals can disrupt/disconnect the association of the symbiotic relationship between trees and mycorrhizae.

Dave

 

[M.D. Vaden]

I will, however, post the last paragraph which sums it up nicely. But please, take the time to read this link in its entirety.

http://www.treedictionary.com/DICT2003/shigo/RHIZO.html

"I believe there is a way to decrease the potential starvation problem. In forests, more wood should be left on the ground, and in cities, more composted wood and leaves should be added in correct quantities to the soil about the base of trees. Incorrect treatments of pruning, watering, planting and fertilizing should be corrected, because they often start the pumps to wobble. If these simple adjustments can be made, rhizosphere starvation will decrease and our trees will lead healthier and longer lives."

One reason I've encouraged some people out here to have fine compost blown on their lawns in thin layers by bark blowers. But fine compost - not bark. That way it's already more disintegrated.

There are many ways to help the soil and plants utilizing the tools and supplies available.

If you like those images in the page, you might like the site of the USDA mycology team based out here. Has some nifty shots in it.

It's pretty interesting how much is happening below the surface.

The article mentioned leaving woody stuff. I think that more about that aspect can be found Googling "Coarse Woody Debris" or "CWD" + "Forest" - there's quite a few articles online about CWD and forest trees.

 

[ddhlakebound]

I am posting this link in the hopes of reaching some of you on the importance of what's happening beneath the tree in the living soil. This article reads well and describes the complexities and delicate balances that many people are unaware of. The associations formed beneath turf and trees are different.

I was going to highlight key portions that I felt deserved focus that pertained to the topic of this thread, but found it to have too much good information to only highlight those key points. I will, however, post the last paragraph which sums it up nicely. But please, take the time to read this link in its entirety.

http://www.treedictionary.com/DICT2003/shigo/RHIZO.html

WOW!!! My head is still spinning a bit, need some digestion of that much info, but a GREAT article. Thanks for posting it.

 

[Glennak]

Good artical Alex Shigo has done a lot for the tree industry and the trees by keeping us informed

 

[BC WetCoast]

A lot of people have commented that having a large mulch ring is imitating forest conditons. This is only true in certain forest types. There are may forest ecosystems - temperate rainforest or the boreal forest, where there is a significant amount of shrubby and herbaceous vegetation under the tree canopy. Many places I've worked have had salal up to 7' tall under the forest canopy.

In the interior dry belt of BC, in the lodgepole pine types, bunch grasses (pine grass being predominant) were the primary understory vegetation.

Even in the southern pine types, understory vegetation is significant or else underburning wouldn't be such a widely used silvicultural tool.

Nutrient cycling is an important consideration here. In the tropical rainforests, material decomposes rapidly and there is rapid nutrient cycling. In the higher elevations of the Rockies, material decomposition is very slow and nutrients cycle much slower.

The thrust of my comments are - don't generalize.

 

[Boa07]

BC, you are right the only really simple response to the initial question is as you write don't generalise.

I'm really not sure what pdqdl was trying to achieve with the question and the way it was posed...however there have been a number of very direct and informed responses notably from Guy and JPS.

It is of course up to each one of us to extend our basic understanding of Tree Biology and how it fits into the wider ecology, if we choose not to then fine, but the info is available some of it free, some of it requiring a fee to the authors and the publishers of papers and books....

Being a CA is a start, but that is all it is...the rest is up to you...Shigo laid the basics out for us over 10yrs ago, your own USDA provides excellent primers for soil biology.

There really are no universal solutions for the variety of environmental circumstances and challenges that beset urban trees.....mulch circles have been put forward as a very simple first aid approach to many of those problems, in doing so much of the complex interrelationships between trees other plants and soil biota has been lost.

 

[John Paul Sanborn]

in doing so much of the complex interrelationships between trees other plants and soil biota has been lost.

That is just the typical urban landscape, which is why I try to recommend other perennials in the mulch ring.

The thrust of my comments are - don't generalize.

Generalizations are a start to education; yes, biome types are not really hard and fast, and most of the remnant populations we deal with are all boundary biomes that mix together.

Then there is the speices and regional variety question: for Quercus macrocarpus so we really want to have a mulch ring, or would a prairie planting be more beneficial. Who would weed it out though? These are treatments that need gardeners.

As for the varietal question; if we do not know the origin of the seed stock is it moot?

My point is that when we are starting off with a concept, then we need to generalize, otherwise the minutiae that may fascinate us will loose the person on the receiving end. Be that the budding arborist, or the potential client.

• turf is an unnatural environment, both by diversity and density.
• trees and grasses require differing biologies
• placing a ring of compost around the base of a tree is the easiest first step to improving the soil around it.

Then again, if we build our business on a few generalities, we will stagnate an be like the landscraper who puts down a 3 inch layer of mulch every year, just because that is what he can sell.

 

[M.D. Vaden]

That is just the typical urban landscape, which is why I try to recommend other perennials in the mulch ring.



Generalizations are a start to education; yes, biome types are not really hard and fast, and most of the remnant populations we deal with are all boundary biomes that mix together.

Then there is the speices and regional variety question: for Quercus macrocarpus so we really want to have a mulch ring, or would a prairie planting be more beneficial. Who would weed it out though? These are treatments that need gardeners.

As for the varietal question; if we do not know the origin of the seed stock is it moot?

My point is that when we are starting off with a concept, then we need to generalize, otherwise the minutiae that may fascinate us will loose the person on the receiving end. Be that the budding arborist, or the potential client.

• turf is an unnatural environment, both by diversity and density.
• trees and grasses require differing biologies
• placing a ring of compost around the base of a tree is the easiest first step to improving the soil around it.

Then again, if we build our business on a few generalities, we will stagnate an be like the landscraper who puts down a 3 inch layer of mulch every year, just because that is what he can sell.

Actually, there are turfgrasses that are supposed to be able to take care of some soil compaction, in ways that mulch could not do.

So I'll never aim for generalization, but each situation figured out one by one.

The mulch often is the "simplist" though where it will work, which tends to be numerous opportunities.

But as I wrote earlier, turf can be topdressed with compost and recieve plenty of the same benefit for soil improvement from Glomalin and Polysaccharides.

 

[pdqdl]

I have noticed a trend here among the various participants of this thread, see if you can see it too:

Somehow cultivating and mowing a crop of turfgrass is un-natural. Well, that is somewhat true. Grass naturally grows long and tall, and still can't compete with all those voracious dicotyledonous weeds and trees; the apex predators of the plant kingdom. About the only place grass outcompetes the trees is where naturally occurring seasonal fires burn up the trees. Grass comes back quick, the trees are done for!

Yet all the efforts of the "tree first" adherents seem to think that our cultivation of trees is somehow different. We spray them, we inject chemicals into their roots and their cambium, we trim them to the shape and condition we prefer, we mulch them with our favorite substitute for what the trees themselves deposit on the ground. We pluck them out of the ground and we put them wherever we feel like, and then we give them whatever competition we see fit, instead of what "naturally" grows into the area they grew into from a naturally planted seedling.

I don't see anything more natural about modern arboriculture than I do about modern turf maintenance. Don't even try to pretend that your chainsaw or your mulch is a substitute for nature.

Regarding competition between lawn and trees: why do you huge mulch ring enthusiasts think that turfgrass is any more competition for trees than the other landscape plants that you happily crowd beneath the trees? Ok, I'll admit that a stark bare 50' diameter circle of mulch is less competition than turfgrass, but to what gain? Whoever told you that a thicket of bushes is any less competition for soil nutrients, sunlight, water, than a thicket of teeny little grasses?

Do you REALLY believe that those evil monocots are killing off the plants that support your livelihood? I personally think that this perspective is a variety of elitism, where YOUR favorite plant is somehow more important than the others.