Last fall we had a 70 year old silver maple removed that had become a safety hazard. The stump was ground and I dug out the wood chips and filled in with a topsoil/compost mixture (I had a truckload delivered to make flower and vegetable beds and to fill in the maple pit). I planted grass and while doing the watering last week noticed a strange spot a few yards away from the maple stump area. Last month my husband had chopped on a root there so the lawn mower wouldn't have to bump over it. I had put some of the soil mixture there to fill in the depression made from his chopping. The dirt there now was soupy with air bubbles in it and had a foul odor. I scooped it into a bucket and dumped it on the ground in the alley by the trash can. I was concerned about what was going on and inquired at the soil forum. It was suggested that it might be hydrogen sulfide caused by an aenerobic situation of waterlogged organic matter. I also wrote to the lawn forum and someone suggested it might be rotting maple sap. Hydrogen sulfide is a poison. I'd much prefer it be sap. Since I took out the dirt last week, exposing the root to the air, it has remained wet and has little bubbles in the liquid over the root and sides of the root, even though Wednesday through Friday were warm breezy days. So I think the liquid is coming from the root and is not a drainage problem, as I thought at first. Would it be normal for a silver maple root to exude sap in the spring if the rest of the tree is gone? Is it normal to smell bad? There's a stink in the general vicinity and it's coming from the root. The goopy, smelly dirt I put in the alley dried out and does not smell now but the smell remains at the root. If this is sap, how long will the liquid continue to come out? If this is sap, why is it a problem just at this one spot and not everywhere else where the stump grinder left severed roots? I live in Richmond VA, zone 7a.