I had a big maple tree cut down. I wonder if it's the roots decaying.
Mushrooms Growing in Lawn
Certified GKH Gardening Expert
The roots would be decaying, and may be contributing to the mushrooms. But the more likely culprit to the mushroom issue would be additional moisture in the soil. Now that the tree is no longer taking up water from the soil, the mushrooms have enough to live on. This article can help with getting rid of them: https://www.gardeningknowhow.com/lawn-care/lgen/eliminate-mushrooms-in-your-lawn.htm