Is this a good time to put peat moss around young trees ?
Deschutes County Oregon
This can be a good time to mulch around trees and other woody plants, but I don't recommend peat moss. Peat moss will soak up all the water and prevent water from getting to the roots of your plants. I recommend this publication on mulching.
If you have further questions, I recommend calling the Deschutes County Extension office and asking for the Plant Clinic.