What kind of trees? I put some spruce & arbor vitae in the ground this time last year, and they did fine. Had some minor winter burn on the south side, but with water and hollytone in the spring they bounced back. I know your climo and soil conditions are different than mine, but I expect they'd do ok. Especially since the ground is wet. My winter burn was caused, in part, by dry soil heading into the winter.