I wrote in last month about my pile of wood chips from a maple removed last fall and how much dirt to fill in the pit. I've planted grass seed and am keeping it moist so the seed will germinate. I see hints of germination. I'm writing now about a problem with one of the lateral roots from this tree. Part was above ground where it a lawn mower would have to bump over it and my husband chopped part of it off so it wouldn't interfere with the mower. I filled in the depression with some of the topsoil/compost mixture. Earlier this week while going around with the hose to keep the ground moist, I noticed that that spot looked strange. On closer inspection I found that the dirt was a sloppy, smelly goo with bubbles it it. I got a 5 gallon bucket and scooped out all the wet goo and dumped on the ground in the alley by the trash can. It rained the next day and the day after I scooped out the puddle, leaving the root exposed to the air. Three days later, which have been warm (in the 60s), sunny, and breezy, the root is glistening with wetness, there are little white bubbles in the wetness, and there is a foul odor in the general vicinity. The dirt I dumped in the alley is now just normal damp dirt and does not smell. After I scooped the dirt out, I wrote to the soil and compost forum here and it was suggested that I was dealing with hydrogen sulfide, which is poisonous. I was thinking then I had a drainage problem with the base of the root keeping rainwater from draining properly and there was some kind of fermentation because of that. But I've never had a drainage problem in that part of the yard and it's strange that it would be concentrated in just that one spot where we had chopped on a root and filled in with dirt. Something is coming from the root, and whatever it is is not good. Do you think it's hydrogen sulfide? Could it be something else? How do you test to find out? Who is qualified to deal with it? If it's hydrogen sulfide, I have a health hazard in my yard. Is this substance normal in the decay process for trees?