I got a sample of soil from under probably imprellis-killed tree. I planted some seed in it indoors in containers to see if any residual effects would affect plants planted in the area. I used bean seed, marigold, grass and tomato. I planted the same in some commercial topsoil, as untreated control. After 12 days all the seed had sprouted. However germination was poor on the soil sample collected under the dead tree. This was possibly due to the very hard and dense nature of the soil, a sandy clay loam. The potentially affected soil was in the front row in the photograph, in the green containers. The soil still supports plant growth. I am not sure if the dense nature of the soil or some other reason reduced the germination and sprouting. Grass seed sprouted fine--not shown.