Orange yellow huge mushrooms
Hello, and thanks for using the Ask an Expert System,
The yellow mushrooms are the reproductive structures of a fungus that is living underground. These structures produce spores that are dispersed by the wind. The fungus is most likely living on the decaying roots of the tree you removed. The underground portion is made up of nearly microscopic threads. If you could dig it up and separate it from the roots and soil it would weigh far more than the above ground fruiting bodies.
There is little you can do about the annual appearance of these mushrooms. They will eventually disappear when the roots of the tree are gone. In the meantime, you can collect the mushrooms as soon as they appear and dispose of them in the garbage. There is no way to kill the fungus without destroying the soil in your yard.