This anecdote is similar Marsha's the caterpillar/oyster mushroom story above-
We had Siberian elms that we had cut down, some years ago. They dropped more branches than we could handle with every heavy snowstorm. They were otherwise beautiful trees, though- it's kind of sad. We planted a large-leaf oak tree and large rose and honeysuckle bushes to replace them.
The stumps were about a foot above ground. I patiently cut the suckers several times a year. Then, one day a couple of years later, I noticed some big funguses growing on the stumps and apparently off of roots from the stumps just at the ground surface. Big pretty orange ones. These funguses seemed to have killed what was left of the poor elm trees, and suckers stopped coming. Now the stumps are slowly decomposing and helping the plants around them.
Your mileage may vary. I don't know, the diesel might make it hard for funguses to grow. The funguses on roots were a small distance away though, so you may get something like this happening with time. Just those little suckers weren't enough to keep the big root system alive, especially when I kept cutting them, and eventually it was too weak to fight off something like those funguses.