Mulching around trees

Q: I would like to add stones around several large trees on my property. Is this a good choice?

A: Stone is not a good mulch choice, although it is used often, for several reasons. First, it retains heat instead of keeping soil and plant roots cool. It will not decompose and will remain in the soil indefinitely. Stone is not a good choice for suppressing weeds. Composted leaf mulch is a good alternative. It has the consistency of soil, suppresses weeds, cools soil temperatures, and is a wonderful soil amendment. Mulches such as shredded bark and nuggets can also be used. Exposed roots of mature trees and shrubs should not be covered with mulch.