As much as I want to get out in the woods and start drilling holes it is plenty early (and since the temps have changed a bit from when i first asked the question). I don't think the frost is all that deep in the woods, at least in NE Otter Tail County. I was out a couple days clearing new trails with the skid steer and I came across a few ash and poplar where the roots came out with the whole tree and I also knocked a couple basketball sized rocks out of the ground also. With a good 1 1/2 to 2 foot of snow in the woods and a Heavy leaf litter I think the ground stays insulated enough that the frost doesn't go as deep as say out in the middle of a field. I hope to be in the woods March 1st starting to get taps in, pending on the weather of course.