The tree roots are not preventing drainage. There are a few possibilities. You could have a low water table and that area is naturally boggy. You could have poorly draining soil. There could be hardpan causing a perched water table. The grading could direct surface water to concentrate in that one location.

It sounds like you have soil with a high organic matter content being soaked with water. This leads to anaerobic conditions. Organic matter in anaerobic conditions produces hydrogen sulfide gas, nasty stuff that smells like rotten eggs.

Without knowing why the soil is remaining boggy, it is hard to suggest a solution. Although filling the hole with sand or decomposed granite would solve the problem of decomposing organic matter producing hydrogen sulfide, it doesn't really address the drainage issue.

If you could show a pic, it might be easier to understand what's going on. As the tree roots decompose under the soil, that area may slowly settle and need to be "refilled" once in a while.

I had a massive Chinese elm tree die due to Dutch elm Disease (sob). They told me that things would grow in the soil/sawdust that remained, but nothing ever has in that huge circle where the tree was, except for some nasty weeds! I've seeded with grass several times.....no go! Nancy

It is a high water table, not low, that would cause a soil to be excessively wet.
Any waterlogged soil, whether there is a lot of organic matter or not, will develp putrid odors due to lack of air in the soil. Hydrogen Sulfide, H2S, is a colorless, flammable, extremely hazardous gas generated by the digestion of organic matter in an airless, anaerobic, atmosphere. H2S is detectable by us in levels around 2 ppm and if you do smell that rotten egg odor leave the area and call other properly equiped and trained people to clean up the area. One problem with H2S is that it can quickly numb your olfactory sensors so you no longer sense its presence.
Is this area lower then the other?

Who would I call? The fire department, the city gas utility, a lawn service company? Will it just go away by itself now that I've removed the sloppy mud? I put the mud in the alley on the ground by the trash can. I could spread it out more to dry. My camera isn't working so I can't take a picture. The ground is level and I haven't had drainage problems there before.

oh damn you're right Kimmsr I did mean high water table. I plead sleep deprivation due to a 10 week old puppy. lol.

oh geez, and I didn't think about decomposing roots. I'm going to say that the tree was drying out the soil to a point where you weren't getting hydrogen sulfide and now that it's gone the soil is going back to boggy, but my brain obviously isn't working that great right now.

The mud I dug out and put in the alley is just damp dirt now, no smell. I spread it out so it will completely dry out. The hole is still smelly. The top of the tree root is glistening with moisture. But it's exposed to the air and ought to dry out. I'm going to leave it alone and check it out again when it looks dry. The amount of sloppy, smelly goop I dug out on Monday took up less than half of a 5 gallon bucket. This spot may be a place where my husband chopped on a tree root that was above ground (to make it easier to cut grass) and I filled in the depression where he had chopped with the topsoil/compost mixture. This is not a boggy area. The soil surrounding the hole is not overly wet.

Another day and the root hasn't dried, despite warm breezy days. The soil around the hole is drying but on top of the root, it's very wet and there are little white bubbles in the wetness. Still a bad odor in the area, though it's not what I think of as rotten eggs. I'm thinking the problem stems from something going on with the root, not a drainage problem. Could it be oozing some kind of sap that's fermented? Needless to say, it's pointless to fill up the hole with anything that just going to be contaminated with this stuff from the root, whatever it is. Do you still think it's hydrogen sulfide or could it be something else? Are there tests for hydrogen sulfide? How long will the root excrete this liquid?

Just a thought:
Leaking sewer pipe? Bad septic system?

The sewer line goes from basement to the street in front of the house, does not go through back yard at all. The bubbly liquid is definitely coming from the root. I'm pretty sure now this is the root we chopped on so it wouldn't be in the way of the lawn mower. I inquired at the lawn forum and it was suggested that the stuff may be rotting maple sap.

My curiosity is peaked by your situation. Have you tried digging down below the 3" in the hole? That's what I'd do to see what the situation is below this point. Even tho there are roots there you should be able to dig around them.

Let us know how this situation unfolds, my curiosity knows no bounds! LOL And I'm kinda bored waiting for the snow to leave so I can garden! :D

It's over a month later and I thought I'd update you on my putrid dirt. I dug the dirt out on one root that had been chopped and left the dirt on another one. There is orange and black and white stuff on the first root and it is still oozing moisture. The second one has the bubbly, sloppy dirt and it has made the surrounding dirt turn orange. I have pictures of both. I'm guessing this has something to do with sap in the roots decomposing. It looks like I can post just one picture per posting, so there will be several postings. This one is of the exposed root.

Here's a picture of the putrid dirt over the root where I did not remove the dirt. It too has the bad smell but the smell is not as bad as it was a couple of weeks ago.

Here's a picture of the putrid dirt over the root where I did not remove the dirt. It too has the bad smell but the smell is not as bad as it was a couple of weeks ago.

Here's another picture of the exposed root.

I missed this thread originally. It sure sounds and looks like the roots are decaying, and since it's all waterlogged, it's doing so anaerobically, producing some odors.

You certainly don't need to call the fire department over smelly tree root decomposition. I would just let it do its thing.

The orange stuff that appears to be growing on the roots is probably fungus, which is the first step in wood decomposition.

You might think about mulching over this area with some wood chips or something else very porous. That way the moisture can wick up and out, but it may help keep some of the odor in if it's bothersome. This whole thing will taper off when the wood rots away enough.

Is this in a low spot, is it boggy around it? I think that was asked earlier but not sure we got an answer.

This is not boggy, not in a low spot. In fact we are near the top of one of the highest hills in Richmond. The odor from the exposed root has gone and the odor on the other root has mostly gone away (if you get close to it, you can smell it--a few weeks ago you could smell it if you were in the general area). The constant wetness has to be from sap in the root. On the exposed root, it's wet where the cut was made in the root. Lesson to be learned from this is not to chop on roots to make it easier to mow grass when a tree has been removed.

When you cut the silver maple did you notice it had an unpleasant odor or a rotted out heartwood?

You could be exposing the bacterial decay that was killing the tree. It's not a pleasant odor.

Heck, silver maple wood on it's own when exposed to a break isn't a pleasant odor...odd quality of the wood's limbs and roots when disturbed/crushed even when totally healthy.

I did not notice any unpleasant odors then. The heartwood had not decayed. We had the tree cut down because two tremendous limbs had split in wind storms in the past couple of years and we feared more limbs would split and crash down and that it had become a dangerous tree.

Based on the photos and your description, I think your stink is nothing more than a result of an anaerobic condition. Get it drained and aired out and the odor will go away. Your challenge is how to get that area to drain, and then fill the hole with something that won't impede drainage. If it were me, I would probably try wood mulch or coarse sand until I was past the drainage issue.

I have a theory that may explain the water. It's spring. If the tree was not dead when it was cut, maybe the roots are doing what tree roots do in the spring: pushing sap (mostly water) up into the tree. Only there is no tree, so you end up with a puddle.

Hi, I'm also having the same issue with a smelly mud at the base of a tree. It's an oak (I don't know what kind) and the mud has been there for about a month. What's different is that the oak is still alive! It is an incredibly tall oak that has healthy looking leaves. It does have some problems though; the mud is on the north side of the trunk, some blackening of the bark is happening on the northwest side, and termites seem to be thriving on the south side. Is my tree dying? If so, I need to get it removed as its so close and so tall that it honestly would cross the entire roof of my house if it falls.

I can provide more details if needed as well as more pictures, just let me know.

Kulianai - all I will say is that doesn't look good, at all.

I'm making a guess by seeing what appear to be root shoots at the base of the tree that the tree is a southern live oak. If that's what it is, they are moderately tolerant of anaerobic conditions and hydric soils. They are found growing in edges of natural wetlands.

If the mud has been there for about a month, the question is why? Is it drainage, or is it a result of damage to the tree/roots. The only way to know for sure, and get a reasonable prognosis for your tree would be to consult with a good arborist.

Upright.

Mystery solved!

I got an arborist out to check out the tree and they say it's slime flux. If you can see in the photo (upper left -- thanks for uprighting it, pupleinopp) the dark coloration continues up the tree for to a height of approximately 6 feet. If I kick off some of the bark, I can see the flux coming out of the oak. What is happening is that the flux is draining down inside the bark to the base of the tree, causing that glob of muddy, smelly soil.

You can read more about it here: http://www.ces.ncsu.edu/depts/pp/notes/oldnotes/od8.html

The wound that caused it was likely from the wood-boring insects that I need to remove from the opposite side of the tree. It should cure itself and go away on its own!

Here is a link that might be useful: NCSU's Cooperative Extension Service's explanation of Slime Flux/ Wet Wood

Cool ! I just learned something valuable. Thanks for the follow-up letting us know the diagnosis, and the reference. My favorite part from the NCSU ref you provided, "More damage can be done to the tree in attempting to cure slime flux than the flux will do alone."

I have this problem currently with a large birch tree. I had some digging done in the yard with heavy equipment and they severed a large root. In the location just around the root, it is very wet and sloppy. It has been a week and still very wet with standing water. There is foam around the water as well. Could this be the same problem as with the maple mentioned previously?

Thanks for posting the pictures of the sloppy stinky mud. A friend had her back yard cleared out where trees (many mulberries etc) had been allowed to grow all over fir about 30 years. About a week later we notice multiple smelly wet spots in the yard. There was oozing slime like the original writer showed in her photos. When my friend dug down, she found roots in most of the holes and we noticed matching slime in some of the remaining tree trunks. Since it is spring, it may be that the roots are still alive and drawing up water that soaks the earth since it has no tree to go into, Thanks so much for the pictures. Very reassuring to see that others have had this problem and there is a logical explanation for it!

I have the same experience happening right now in my driveway. My driveway is just wheel tracks, but i noticed this wet patch with a tennis ball sized mound of dirty foam coming out the middle. I thought it may have been acid from a car battery, but it had no real smell. it is only 3 days old now. my drive comes through a grove of trees and that is where it is at.

Lots of gases have no smell. It could be something innocuous, or it could be methane. Who knows, you might have to change your name to Jed Clampett. Seriously though, get someone to look at it. I was working on a house one time, smelled gas while I was mowing the lawn, and called the gas company. The guy came right out with one of those 'snifffers'. Sure enough... it was huge leak. In 30 mins the gas company had the entire area taped off and was digging it out. You never know.

Except that natural gas odorant is extremely identifiable. Unless you have a transmission line which is not odorized. But people would normally know that as the easement is kept free of trees and there are pipeline signs.

I bet this is just dead tree roots decaying.